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NON-TARGET IMPACTSOF THE HERBICIDE

GLYPHOSATE

A COMPENDIUM OFREFERENCES AND ABSTRACTS

4THEDITION

INFORMATION REPORTAPPLIED MAMMAL RESEARCH INSTITUTE


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RATIONALE AND BACKGROUND

The original concept of a compendium of references and abstracts outlining the non-target

impacts of the herbicide glyphosate arose from the apparent incomplete and scattered sources of

information on this subject. A common complaint from both lay and professional people is: What

research has been done on non-target impacts of glyphosate and how do we access this information?In fact, from the computerized literature search which was conducted to identify studies of non-target

impacts of glyphosate, the information in this fourth edition of the compendium was extracted from

several thousand references covering environmental impacts, toxicology, efficacy, and human health.

Thus, there is considerable literature base for glyphosate and this compendium evolved as a means of

providing, in as complete a manner as possible, a collection of titles and abstracts of articles reporting

on the non-target impacts of this herbicide.

As compilers of this document, we have conducted research on the non-target effects of

glyphosate over the past 18 years. This work has focused primarily on small mammal populations in

forestry and agriculture. Additional work was conducted on black-tailed deer, fish, daphnids, and

diatoms (algae) as part of a major field study. To date, with coworkers, there are 18 journal

publications outlining our work on the non-target impacts of glyphosate. Much of our earlier work on

mammals is summarized in the chapter Effects of Glyphosate on Selected Species of Wildlife: from

the book The Herbicide Glyphosate published in 1985.

Druscilla S. Sullivan, M.Sc.

Research Associate

Thomas P. Sullivan, Ph.D.

Director and Research Scientist

Applied Mammal Research Institute

11010 Mitchell Avenue, R.R. #3,

Summerland, B.C., Canada

V0H 1Z0

February 1997


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ORIGIN AND USE OF COMPENDIUM

This compendium is designed as an Information Report to provide an objective assessment of

the effects of glyphosate on non-target species and ecosystems. The majority of references (scientific

journals and proceedings of symposia) up to and including 1993 were extracted from a computerized

literature search of the following sources:

AGRICOLA (Agriculture 1970 - 1990)

CHEMICAL ABSTRACTS (American Chemical Society 1973 - 1993)

AQUAREF (Canadian Water Resources References 1970 - 1992)

ASFA (Aquatic Sciences and Fisheries Abstracts 1978 - 1993)

BIOSIS (Biological Abstracts 1969 - 1993)

CAB (Commonwealth Agriculture Bureau Abstracts 1972 - 1993)

NTIS (National (U.S.) Technical Information Service 1964 - 1990)

The literature search via DC-ROM for this edition was from:

BIOSIS (Biological Abstracts 1993 - 1996)

LIFE SCIENCES COLLECTION (1993 - 1996)

MICROLOG (1993 - 1996)

MEDLINE (1966 - 1996)

NIOSH (U.S. National Institute for Occupational Safety and Health 1966 - 1996)

UKIH (United Kingdom Industrial Health 1966 - 1996)

Titles and abstracts have been reproduced exactly as they appear in the original article or as

abstracted by the source system. In the case of journal articles without a formal abstract, a summary

of the study has been abstracted by the compilers and this is clearly indicated by an asterisk (*).

The compendium is composed of ten sections: Aquatic Intertebrates and Algae, Biodiversity -

Conservation and Habitat Restoration/Alteration, Birds, Fish, Human Health, Mammals, Microflora and

Fungi, Plant and Soil Residues, Terrestrial Invertebrates, and Water Quality. All titles and abstracts of

pertinent references with author(s) and publication outlet are listed alphabetically in each section.

Some references do not have abstracts and represent those publications which could not be obtained

by the compilers. References from outside North American are identified by country, when known, to

assist the reader. References which report on species representing more than one section (e.g. fish

and aquatic invertebrates) will appear in each section.

We recommend that users do not cite information from the abstracts, but rather they refer to

the original source, if at all possible.


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TABLE OF CONTENTS

I. AQUATIC INVERTEBRATES AND ALGAE......................................................1

II. BIODIVERSITY, CONSERVATION, AND HABITATRESTORATION/ALTERATION .......................................................................12

III. BIRDS ..............................................................................................................37

IV. FISH .................................................................................................................46

V. HUMAN HEALTH.............................................................................................57

VI. MAMMALS.......................................................................................................72

VII. MICROFLORA AND FUNGI.............................................................................96

VIII. PLANT AND SOIL RESIDUES ......................................................................127

IX. TERRESTRIAL INVERTEBRATES ...............................................................160

X. WATER QUALITY..........................................................................................171


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1. Anton, F. A., M. Ariz, M. Alia, W. Sloof, and H. deKruijf (editors). 1993. Ecotoxic effects of fourherbicides (glyphosate, alachlor, chlortoluron and isoproturon) on the algae Chlorel lapyrenoidosaChick. Proceedings o f the Second European Conference on Ecotox icology.

Science Total Enviro nm ent , pp. 845-51 .Herbicides are chemicals used in crop protection to control weeds that could affect freshwater

microalgae of natural ecosystems. In this work the ecotoxic effects of several herbicides on theChlorophyceaChlorella pyrenoidosaChick. (Chlorella emersoniivar. globosa) have been studied usingan ecotoxicological bioassay. All herbicides (glyphosate, chlortoluron with terbutryne, isoproturon andalachlor) were commercial and technical products. The EC sub(50) and NOEC values (96-h) ofherbicides were calculated to reveal the toxic effects on microalgae caused by them. Isoproturon(50%) and chlortoluron (43%) with terbutryne (7%) were the more toxic herbicides to Chlorella

pyrenoidosa. The lower ecotoxic effects that inhibit the algal populations had occurred when algaewere exposed to technical and commercial glyphosate. Commercial alachlor and technical andcommercial chlortoluron had values between the most and least ecotoxic herbicides that were tested.(Spain) .

2. Austin, A. P., G. E. Harris, and W. P. Lucey. 1991. Impact of an organophosphate herbicide(glyphosateR) on periphyton communities developed in experimental streams. Bul let in ofEnvironmental Contaminat ion and Toxicology 47: 29-35.

(*) The effects of low-level concentrations of glyphosate (1-300 g/L) and nutrient enhancement onalgal biomass in field-based stream troughs were studied. A 2-week period preceded measurablebiomass in all troughs. Although the magnitude of biomass accrual differed between control troughsand those receiving glyphosate, all troughs exhibited biomass increase:decrease cycles. Except for theinitial cycle, biomass in the control troughs was less than in those receiving glyphosate. The growth incontrol+nutrients recovered slowly prior to glyphosate addition following the first cycle, unlike nutrientonly troughs. At all three glyphosate concentrations, post-glyphosate growth decreases were followedby biomass accrual values larger than in either control. An assessment of algal species compositionindicates all numerically dominant species were present in all troughs throughout the experiment; somepatchiness was observed over time, between troughs and treatments. However, with the exception of

N. acicularis, no species were lost following the addition of glyphosate. Numerically, diatoms weremost abundant, withAchnanthes minutissimaincreasing to dominate all troughs, although representingonly a minor proportion of biovolume. Glyphosate did not appear to inhibit biomass accrual nor was itlethal to any of the pre-treatment dominant species. In troughs receiving the biocide, enhanced growthabove control values suggested the phosphate constituent of this herbicide might be acting as anutrient. The addition of glyphosate to a periphyton community appears to have little effect onsubsequent successional patterns. If the primary producer component of periphyton biofilm can useglyphosate or the surfactant as an alternate source of phosphorus, then, irrespective of othertoxicological considerations, glyphosate-induced eutrophication of coastal oligotrophic waterways couldindirectly affect salmonid habitat and other aquatic resource management concerns. Theconcentrations used in this study are within the range known to occur in lotic habitats followingprecipitation events or as a result of direct application.

3. Buhl, K. J., and N. L. Faerber. 1989. Acute toxicity of selected herbicides and surfactants tolarvae of the midge Chironomu s ripar ins. Archives of Environm ental Contaminat ion andToxicology 18: 530-536.

The acute toxicities of Eradicane (EPTC), Fargo (tri-allate), Lasso (alachlor), ME4 Brominal(bromoxynil), Ramrod (propachlor), Rodeo (glyphosate), Sencor (metribuzin), and Sutan (+) (butylate)and 2 surfactants (Activator N.F. and Ortho X-77) to early fourth instar larvae of C. riparinsweredetermined under static conditions. In addition, technical grade alachlor, tri-allate, metribuzin andpropachlor were tested for comparison with the formal dated products. The relative toxicity of thecommercial formulations varied considerably. EC50 values ranged from 1.23 mg/l for Fargo to 5600mg for Rodeo. Fargo, ME4 Brominal and Ramrod were moderately toxic to midge larvae. Lasso,


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Sutan (+) and Eradicane were slightly toxic; and Sencor and Rodeo were practically non-toxic. The 48-h EC50 values of the two surfactants were nearly identical and were moderately toxic to midges. Fortwo of the herbicides in which the technical grade material was tested, the inert ingredient in theformulations had a significant effect on the toxicity of the active ingredient. Fargo was twice as toxic astechnical grade tri-allate, whereas Sencor was considerably less toxic than technical grade metribuzin.

A comparison of the slope function values indicated that the toxic action of all the compounds occurredwithin a relatively narrow range. In general the order of toxicity to C. riparinswas similar to those for

other freshwater invertebrates and fish. A comparison between estimated max. herbicide concentrationin runoff and results of acute tests indicated that Ramrod, ME4 Brominal and Lasso pose the greatestdirect risk to midge larvae during a storm event.

4. Buikema, A. L., E. F. Benfield, and B. R. Niederlehner. 1981. Effects of pollution on freshwaterinvertebrates. Journal o f the Water Pol lut ion Control Federat ion 53: 1007-15.

5. Christy, S. L., E. P. Karlander, and J. V. Parochetti. 1981. Effects of glyphosate on the growthrate of Chlorel la. Weed Science 29: 5-7.

Growth rates, in terms of cell doublings per day, were determined for cells of C. sorokinianainoculated into media containing from 5.91 x l0 sup-sup 6M to 591 x 10 sup-sup 6M glyphosate.Comparisons with a control, which supported 10.4 doublings/day, showed growth only slightly reducedat 5.91 x 10 sup-sup 6M and 11.8 x 10 sup-sup 6M, with averages of 9.7 and 9.5 doublings/day;

reduced by more than half at 17.7 x 10 sup-sup 6M with an average of 4.4 doublings/day; andprevented at all higher concentrations. In addition to completely preventing growth at 23.7 x 10 sup-sup6M and above, glyphosate seemed to cause a deterioration of the inoculum cells. Filtering the mediacontaining 5.91 x 10 sup-sup 6M 11.8 x 10 sup-sup 6M, and 17.7 x 10 sup-sup 6M through kaoliniteprior to introduction of the alga reduced the inhibition previously noted at 17.7 x 10 sup-sup 6M andresulted in growth rates from 9.1 to 9.5 doublings/day.

6. Environment Canada. 1990. Pest ic ide research and monitorin g annu al report 1988-1989.Environment Canada , ISBN 0-662-18461-0; Publication no: DSS cat no En 40-11-13-1989E.

See Water Quality Section.

7. Ernst, W. R., R. Morash, W. Freedman, and K. Fletcher. 1987. "Canada Surveillance Report ."Measurement of the environmental effects associated with forestry use of Round up. EP-5-AR-87-8.

See Plant and Soil Residues Section.

8. Faust, M., R. Altenburger, W. Boedeker, and L. H. Grimme. 1994. Algal toxicity of binarycombinations of pesticides. Bul let in of Environmental Contaminat ion and Toxicology 53 , no.1: 134-41 .(Germany).

9. Folmar, L. C. 1978. Avoidance chamber responses of mayfly nymphs exposed to eightherbicides. Bul let in of Environmental Contaminat ion and Toxicology 19: 312-18.

In a Y-shaped avoidance maze, mayfly (Ephemerella walkeri) nymphs avoided the highest testconcentrations of CuS04(0.001-0.1 mg CU

+2/L, diquat (0.01-1 mg/L), and Roundup (0.1-10 mg/L), butdid not avoid 2,4-D DMA (2,4-D dimethylamine salt) (1-100 mg/L), acrolein (0.001-0.1 mg/L), dalapon

(0.1-10 mg/L), xylene (0.1-10 mg/L), and Aquathol K (0.1-10 mg/L). The nymphs displayed a markedattraction to 1 mg dalapon/L. The sensitivity of mayfly nymphs to these herbicide pollutants iscompared with the sensitivity of rainbow trout fry, and the results are discussed with regard to theimpact of herbicide pollution on sport fisheries.

10. Folmar, L. C., H. O. Sanders, and A. M. Julin. 1979. Toxicity of the herbicide glyphosate andseveral of its formulations to fish and aquatic invertebrates. Archives of Environm entalToxicology and Contaminat ion 8: 269-78.

See Fish Section.


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11. Gardner, S. C., and C. E. Grue. 1996. Effects of Rodeo registered and Garlon registered 3A onnontarget wetland species in central Washington. Environmental Toxicology and Chemist ry15, no. 4: 441-51 .

See Fish Section.

12. Goldsborough, L. G., and D. J. Brown. 1987. Effects of aerial spraying of for estry herbicides onaquat ic ecosystems . Part II I. Bioassay of the effect of glyph osate on carbon f ixat ion b y intact

per iphyton comm uni t ies . Mani toba Environment and Wo rkplace Safety and Heal th. WaterStandards and Studies Report 873.

As part of a threeyear study examining potential effects of herbicide use in forest managementon adjacent aquatic ecosystems, artificial substrata (acrylic rods) were positioned in shallow waterwithin six experimental study ponds near Pine Falls (96o10'W, 50o37'N) during late summer. Thesubstrata were permitted to colonize with periphytic algae for a period of 41 to 50 days, after whichsamples were collected and exposed in the laboratory to concentrations of glyphosate (added as thecommercial formulation Roundup) ranging from 0 to 1800 mg/L. Carbon fixation rates during the firstfour hours after herbicide treatment were measured, and the change in rate relative to untreatedcontrols was used to assess the shortterm effects of glyphosate on algal photosynthesis. Effects ofglyphosate treatment on carbon fixation were not detected in samples from any pond at concentrationsless than about 0.89 mg/L. Carbon fixation occurred at the highest tested concentration. EstimatedEC50values for Pine, Hike and Birch Ponds ranged from 35.4 to 69.7 mg/L glyphosate. Based on the

estimated glyphosate concentration which could result from a hypothetical application of 2.5 L/haRoundup to the study ponds (0.06-0.10 mg/L), no immediate effects of herbicide treatment onperiphytic algal photosynthesis are predicted.

13. Hartman, W. A., and D. B. Martin. 1984. Effect of suspended bentonite clay on the acute toxicityof glyphosate to Daphnia pulexand Lemna minor. Bul let in of Environm ental Contaminat ionand Toxicology 33: 355-61.

14. . 1985. Effects of four agricultural pesticides on Daphnia pulex, Lemna minor, andPotamogeton pectinatus. Bulletin of Environmental Contamination and Toxicology 35: 646-51.

The toxicity of glyphosate, atrazine, alachlor and carbofuran to D. pulex, L. minorand P.pectinatuswas studied at 0.1-10.0 mg/L and the effect of suspended sediment on the toxicities of thesepesticides was also examined. Carbofuran (10 mg/L) had no toxic effects on L. minorwith or without

suspended sediment. Atrazine and alachlor were toxic to Lemna, and the presence of suspendedsediment was relatively unimportant in reducing or increasing the toxicity. The above chemicals had noeffect on sprouting of P. pectinatus.

15. Henry, C. J. 1992. "Effects of Rodeo herbicide on aquatic invertebrates and fathead minnows. "M.Sc. Thesis, South Dakota State University. 63 p.

(*) I evaluated the effects of Rodeo on the survival of six species of invertebrates and fatheadminnows by placing them in enclosures in eight North Dakota wetlands that were aerially treated withRodeo at 5.8 L/ha and in four that were untreated. The number of animals alive and dead were thencounted up to 21 days post-treatment. In field trials, no significant differences (P>0.05) occurred inmortality rates of invertebrates between treated and reference wetlands. Laboratory static acutetoxicity testing was done on the same species to determine EC50's or LC50's of Rodeo, X-77 Spreader,and Chem-Trol both individually and in mixtures. Rodeo alone and the field application mixture of all

three chemicals were rated as practically nontoxic (100-1000 mg/L), X-77 as moderately toxic (1-10mg/L), and Chem-Trol as an insignificant hazard (>1000 mg/L). The field application mixture wassignificantly more toxic than Rodeo by itself with X-77 being the most toxic component. I found noevidence of synergistic effects among the three chemicals. The most toxic EC50 for Rodeo of allspecies tested was 485 times the highest concentration of glyphosate (0.600 mg/L) found in wetlandwater samples. I concluded that the benefits to waterfowl by restoring degraded habitat through the useof Rodeo outweigh the limited chance of invertebrate populations being greatly reduced or eliminatedas a result of the treatment. Recommendations are given for future research and for managing cattailsin wetland complexes with Rodeo herbicide.


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16. Henry, C. J., K. F. Higgins, and K. J. Buhl. 1994. Acute toxicity and hazard assessment ofRodeo, X-77 Spreader, and Chem-Trol to aquatic invertebrates. Archives of Environm entalContaminat ion and Toxicology 27 , no. 3 : 392-99 .

The herbicide Rodeo provides waterfowl managers with an effective chemical tool for creatingopen water habitats in wetlands if its use does not adversely affect native invertebrate communities.The survival of caged Chironomusspp. (midge), Hyalella azteca(amphipod), Stagnicola elodes(pondsnail), and Nephelopsis obscura (leech) was assessed in prairie pothole wetlands treated by air with atank mixture of Rodeo, the surfactant X-77 Spreader, and the drift retardant Chem-Trol at a raterecommended for controlling cattails. Laboratory studies were then conducted to determine the acutetoxicities of Rodeo, X-77 Spreader, and Chem-Trol, individually and in simulated tank mixtures, to thesame invertebrates and to Daphnia magnain reconstituted water representative of these wetlands.

17. Hernando, F., M. Royuela, A. Munoz-Rueda, and C. Gonzalez-Murua. 1989. Effect of glyphosateon the greening process and photosynthetic metabolism in Chlorel la pyrenoidosa. Journal ofPlant Phys iology 134: 26-31.

Chlorella pyrenoidosa pringsheim(211/8 A) was grown photoautotrophically using the herbicide,glyphosate (n-(phosphonomethyl)-glycine), in concentrations ranging from 0.1 mM to 1 mM.Chlorophyll and carotenoid content, greening process, photosynthetic and respiration rates, andphotosynthetic electron transport activities were investigated. Glyphosate decreased cell density andphotosynthetic pigment content; 1.0 mM did not allow growth. Bleached cells were used for thegreening process. Glyphosate had two different effects upon photosynthetic pigments: inhibition ofchlorophyll synthesis and a decrease in carotenoids. Oxygen uptake was not affected, but oxygenevolution was strongly inhibited. The results suggest that glyphosate acts as an electron transportinhibitor, acting on both photosystems, but its effect was greater on PS II than PS I.

18. Hildebrand, L. D., D. S. Sullivan, and T. P. Sullivan. 1980. Effects of Roundup herbicide onpopulations of Daphnia magnain a forest pond. Bul let in of Environmental Contaminat ion andToxicology 25: 353-57.

(*) D. magnapopulations were arranged in pens in 4 stations in an experimental pond todetermine the effects of Roundup (glyphosate). Each station was sprayed with one of the following:pond water alone, field dose (2.2 kg/ha), 10 x field dose and 100 x field dose of Roundup. Survival ofD. magnapopulations was not significantly altered between control and experimental treatments at 2, 4

and 8 days. This study, which attempted to simulate aerial application of Roundup herbicide, indicatedthat there were no detectable effects on D. magna.

19. Holck, A. R., and C. L. Meek. 1987. Dose-mortality responses of crawfish and mosquitoes toselected pesticides. Journal of the Am erican Mosqu i to Control Assoc iat ion3: 407-11.

A study was conducted to determine the toxicities (LC50s) of several pesticides on thecommercially important red swamp crawfish, Procambarus clarkii, and 3 mosquito species common inLouisiana (U.S.A.) ricelands-Anopheles quadrimaculatus, Culex salinariusand Psorophora columbiae.Pesticides tested in laboratory bioassays included Bacillus sphaericus, B. thuringiensisvar. israelensis,Bendiocarb, glyphosate, isostearyl alcohol, Malathion, Propoxur, Resmethrin synergized with PiperonylButoxide (PBO) and Thiobencarb. Isostearyl alcohol was the least toxic compound to crawfish, with aLC50 of > 10,000 ppm, while resmethrin + PBO (1:3 ratio) was the most toxic with a LC50 of 0.00082ppm. The herbicides Glyphosate and Thiobencarb were the least toxic compounds for the mosquito

species tested, while B. t.var israelensisand Resmethrin + PBO were the most toxic.

20. Holtby, L. B., and S. J. Baillie. 1989. Effects of the herbic ide "Roun dup" (glyphosate) onperiph yton in Carnat ion Creek, Brit ish Columb ia. Proceedings of the Carnation Creek HerbicideWorkshop. Forest Resource Development Agreement, B.C. Ministry of Forests, ForestryCanada, B.C. FRDA Report 063, pp. 224-31.

Periphyton standing crops and accumulation rates were monitored at several sites in the main-stem and valley-bottom tributaries of Carnation Creek for 18 months after the herbicide ROUNDUPwas applied at a rate of 2.2 kg glyphosate/ha to much of the valley floor of the watershed. One


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sidechannel was oversprayed. There is evidence of direct toxicity of some herbicide component twoweeks after the mid-September application. In the year following spraying there was some localizedenhancement of production as the periphyton responded to increased levels of phosphorusimmediately downstream of the over-sprayed side-channel.

21. . 1989. Litter-fall and detrital decomposition rates in a tributary of Carnation Creek, BritishColumbia, oversprayed with the herbicide Roundup (glyphosate). Forest ResourceDevelopment Agreement, B.C. Proceedings of the Carnat ion Creek Herbic ide Worksh op.Ministry of Forests, Forestry Canada. FRDA Report 063, pp. 232-49.

Litter-fall was measured in the riparian zone of a tributary oversprayed with the herbicideROUNDUP (glyphosate) for 18 months after application. Defoliation of the riparian zone of the tributaryreduced deciduous litter-fall to approximately 6% of the expected total deposition of 300 g.m2.yr-1.Coniferous litter was a minor component of all treatment and control sites, averaging less than 1% ofthe total. At the three control sites coniferous litter-fall increased by an average of 296% in the yearafter spraying compared to the year before, but in the treatment area the increase was only 36%. Litterdecomposition rates in water were variable in the three summers during which measurements weremade. Decomposition rates were greatest in the oversprayed tributary and lowest in the controltributary. Between-site differences in decomposition rates were probably the result of differences intheir macro-invertebrate communities. Most of the between-year variability in decomposition rates was

accounted for by differences in stream temperatures. The herbicide had no measurable effects onmacro-invertebrate abundance or community composition for 22 months after application.Decomposition rates in the over-sprayed tributary increased in the summers after spraying, partly as aresult of increased summer temperatures that resulted from defoliation of the riparian zone.

22. Hutber, G. N., L. J. Rogers, and A. J. Smith. 1979. Influence of pesticides on the growth ofcyanobacteria. Zeitschr is t Fur Al lgemeine Mikrobiologie 19: 397-402.

Two unicellular and 2 filamentous cyanobacteria (blue-green algae) were exposed underconditions optimal for photoautotropic growth to 11 pesticides. Low concentrations (0.01-5 ppm) ofdiuron, atrazine and paraquat inhibited growth. With MCPA, MCPP, 2,4-D, milstem, and ethrel, markedinhibitory effects were achieved only at concentrations above 100 ppm. Growth was inhibited byglyphosate, DDT, and thiram at intermediate concentrations. In some cases, the effective concentrationof the pesticide varied considerably with the organism tested. (Germany) .

23. Kafarov, R. S., L. A. Bakumenko, and D. N. Martorin. 1985. Effect of herbicides onphotosynthetic reactions in plants and algae. Agrokhimiya 11: 99-104.(Soviet Union).

24. Kallqvist, T., M. I. Abdel-Hamid, and D. Berge. 1994. Effects of agricultural pesticides onfreshwater plankton communities in enclosures. Norwegian Journ al of Agricu l tural SciencesSupplement13 : 133-52 .(Norway).

25. Kreutzweiser, D. P., P. D. Kingsbury, and J. C. Feng. 1989. Drift response of streaminvertebrates to aerial application of glyphosate. Bul let in of Environmental Contaminat ion andToxicology 42: 331-38.

A study was conducted to determine the drift response of aquatic invertebrates to glyphosatecontamination from an aerial application of Roundup (R) to the Carnation Creek watershed inSeptember 1984. Drifting invertebrates were collected from three sampling sites in the watershed andstream water was collected for analysis of residual glyphosate. The sampling sites were located in themain channel of Carnation Creek, in C Creek (a 1000 m ephemeral tributary) and in 1600 Tributary (an800 m stream directly oversprayed). Glyphosate was applied as Roundup (R) at a concentration of 2.0kg ai/ha in a total volume of 252 L/ha over four separate days. The application of glyphosate on oradjacent to small tributaries of Carnation Creek did not result in undue disturbance of streaminvertebrates. Drift densities of most aquatic invertebrates did not increase in response to the herbicideapplications. None of the post-spray mean drift values for total invertebrate catches were significantly


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higher than pre-spray mean densities. However, the drift response of two organisms, Gammarussp.and Paraleptophlebiasp., may suggest a slight and ephemeral herbicide induced disturbance in anddownstream of the treatment areas. In tributary 1600, residual glyphosate in integrated water samplesdid not exceed 162 g/L and was less than 50 g/L within 10 h after the overspray.

26. Luetjen, K., I. Girardet, R. Altenburger, M. Faust, and L. H. Grimme. 1988. The effect ofglyphosate and phosphinothricin on single celled green algae. Communicat ions of the Federal

Biolo gical Inst i tute for Agricu lture and Forestry Berl in-Dahlem, 46th German Plant Protect ionConvent ion. No. 245.(Germany).

27. Maule, A., and S. J. L. Wright. 1984. Herbicide effects on the population growth of some greenalgae and cyanobacteria. Journal of App l ied Bacter io logy 57: 369-79.

Six herbicides were tested for their effects on the population growth of a range of green algaeand cyanobacteria by an easily replicated low-volume liquid culture technique using Repli-dishes.Diuron, propanil and atrazine were most inhibitory, chlorpropham was intermediate and MCPA andglyphosate were least inhibitory. Chlorpropham was more inhibitory to green algae than tocyanobacteria. The effects of chlorpropham and 3-chloroaniline, a metabolite, on populations of thecyanobacteriumAnacystis nidulansand the alga Chlamydomonas reinhardtiwere monitored in largerscale batch cultures. Both compounds reduced the growth rate although in some cases there was

partial recovery. 3-Chloroaniline was less inhibitory than the parent herbicide chlorpropham. (UnitedKingdom).

28. McLeay, D. 1988. Development of a bioassay protocol for evaluating the toxic risk to regionalfisheries resources posed by forest-use herbicides. Forest Resource Development Agreement,B.C. Ministry of Forests, Forestry Canada, B.C. FRDA Report 039. 57 p.

See Fish Section.

29. Medina, H. S. G., M. E. Loptata, and M. Bacila. 1994. The response of sea urchin eggembryogenesis towards the effect of some pesticides. Arquivos De Biologia e Tecnologia(Curit iba) 37 , no. 4 : 895-906 .

Experiments were carried out on the effect of some pesticides on the embryonic developmentof fertilized eggs from the sea urchin Lytechinus variegatusLamarck, var. atlanticus. The eggs ere

fertilized in a nursery specially designed for such purpose. Three minutes after the formation of thefertilizing membrane, suitable amounts of Trifluraline, Folidol 600, Roundup, Sulfosate and K-Otrinewere added to the fertilized egg and their effect observed by microscopic examination. It has beenfound that specific alterations on the embryonic forms of the egg development were caused by thedifferent pesticides used. The observation began after the addition of the pesticide to the eggsuspension and was carried out for 24 hours up to the stage of pluteus. (Brazil) .

30. Nishiuchi, Y. 1978. Toxicity of formulated pesticides to some fresh water organisms. SuisanZoshoku 25: 148-50.(Japan).

31. Payne, N. J., J. C. Feng, and P. E. Reynolds. 1990. Off-target deposits and buffer zones requiredaround water for aerial glyphosate applications. Pest ic ide Science 30: 183-98.

Off-target deposit has been quantified from various silvicultural glyphosate application methodsand an estimate made of the buffer-zone widths required around water to protect fish and theirinvertebrate food species from possible toxicological effects. To overcome the difficulty of estimatingdifferent buffer widths to meet the various use conditions encountered, a realistic worst-case scenariowas chosen for small-drop drift and data were collected accordingly. Three glyphosate applicationmethods were tested, employing a helicopter equipped with a 'Microfoil' boom, a 'Thru Valve Boom'and D8-46 hydraulic nozzles respectively. Airborne glyphosate and off-target glyphosate deposits onground sheets and foliar surfaces were measured at downwind distances between 50 and 200 m frommultiple overlaid crosswind swaths. Over this distance airborne glyphosate decreased by factors of 3-130, ground deposits by factors of 4-2200, and foliar deposits by factors of 5-100. In general airborne


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glyphosate and off-target deposit was highest from the D8-46 application, and lowest from the'Microfoil' boom application. Using these measurements, mathematical equations were formulated topredict glyphosate deposits on water surfaces downwind of multiple swath applications, andcalculations made for 100-ha applications. Large-drop drift was also calculated using a ballistic model.

An estimate was then made of buffer widths required around water bodies to prevent toxicologicaleffects from small- and large-drop drifts, using reported glyphosate toxicities to salmon, rainbow troutand various aquatic invertebrates. A buffer width of 25 m around water bodies limits mortality in

populations of salmon, rainbow trout and aquatic invertebrates to less than 10% for the applicationmethods employing the 'Microfoil' and 'Thru Valve' Boom. For the third application method a 30-mbuffer width is suggested.

32. Payne, N., J. Feng, and P. Reynolds. 1989. Off-target deposit measurements and buffer zonesrequired around water for various aerial applications of glyphosate. Proceedings o f theCarnat ion Creek Herbicide Worksh op. Forest Resource Development Agreement, B.C. Ministryof Forests, Forestry Canada. FRDA Report 063, pp. 88-109.

See Fish Section.

33. Peterson, H. G., C. Boutin, P. A. Martin, K. E. Freemark, N. J. Ruecker, and M. J. Moody. 1994.Aquatic phyto-toxicity of 23 pesticides applied at expected environmental concentrations.Aquat ic Toxicology (Amsterdam) 28 , no. 3-4 : 275-92 .

Environment Canada uses an Expected Environmental Concentration (EEC) in evaluating thehazard of pesticides to nontarget aquatic organisms. This concentration is calculated by assuming anoverspray of a 15 cm deep waterbody at the label application rate. The EEC of pesticides is thenrelated to the EC50 (concentration causing a 50% reduction in a chosen toxicity endpoint) for a givenaquatic test organism. At present, the use of an uncertainty factor is suggested in the literature if only afew species are tested because of important interspecific differences in pesticide sensitivity. Thephytotoxicity of the EEC of 23 different pesticides to ten algae (24 h inhibition of 14C uptake) and onevascular plant (7-day growth inhibition) was determined in an effort to examine the question ofinterspecific sensitivity and its relation to the development of pesticide registration guidelines.Chemicals included five triazine herbicides (atrazine, cyanazine, hexazinone, metribuzin, andsimazine), four sulfonylurea herbicides (chlorsulfuron, metsulfuron-methyl, ethametsulfuron-methyl,triasulfuron), two phenoxyalkane herbicides (2,4-D and MCPA), two pyridine herbicides (picloram andtriclopyr), a substituted urea, an amine derivative, and an imidazolinone herbicide (tebuthiuron,

glyphosate and imazethapyr, respectively), a bipyridylium (diquat), a hydroxybenxonitrile (bromoxynil),an aldehyde (acrolein) and an acetanilide (metolachlor) herbicide, as well as two carbamateinsecticides (carbofuran and carbaryl) and a triazole derivative fungicide (propiconazole). Testorganisms were selected based on ecological relevance and present use in test protocols. Organismsincluded green algae (Scenedesmus quadricaudaand Selenastrum capricornutum), diatoms (Nitzschiasp. and Cyclotella meneghiana), cyanobacteria (Microcystis aeruginosa, Oscillatoriasp.,Pseudoanabaenasp.,Anabaena inaequalisandAphanizomenon flos-aquae) and a floating vascularplant, duckweed (Lemna minor). The five triazine herbicides, acreolein and diquat inhibited the carbonuptake of all algae, diatoms and cyanobacteria by more than 50%. Two other pesticides, carbaryl +tebuthiuron caused more than 50% inhibition in 90% of the algae tested. Nine of the 23 pesticides, fiveof which were triazine herbicides, were therefore highly phytotoxic to algae. Twelve pesticides inhibitedgrowth of duckweed by more than 50%. Once again, all five of the triazine herbicides were among thisgroup, as well as three sulfonylurea herbicides and acrolein, diquat, metolachlor and tebuthiuron.

Duckweed was the most sensitive organism tested, being equally affected by all pesticides causingalgal phytotoxicity (with the exception of carbaryl), as well as being acutely affected by sulfonylureaherbicides. Green algae were least sensitive to diquat; diatoms and one cyanobacterium were the onlyorganisms that showed sensitivity to glyphosate. Through testing the phytotoxicity of a variety ofagricultural pesticides to a wide range of algal taxa, it is evident that there are considerable differencesin sensitivity among species and that the use of an uncertainty factor is necessary to provide anacceptable margin of safety in evaluating the hazard presented by these chemicals to the aquaticenvironment.


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34. Reinbothe, S., A. Nelles, and B. Parthier. 1991. N-Phosphonomethylglycine Glyphosatetolerance in Euglena-graci l isacquired by either overproduced or resistant 5enolpyruvylshikimate-3-phosphate synthase. European Journal of Biochemist ry 198: 365-74.

Photautotrophic cells of Euglena graciliscan be adapted to N-(phosphonomethyl)glycine(glyphosate) by cultivation in media with progressively higher concentrations of the herbicide. Twodifferent mechanisms of tolerance to the herbicide were observed. One is characterized by theoverproduction and 40-fold accumulation of the target enzyme, 5-enolpyruvylshikimate-3-phosphatesynthase, in cells adapted to 6 mM N-(phosphonomethyl)glycine. The other is connected with aherbicide-insensitive enzyme. No evidence was obtained for the involvement of the putativemultifunctional arom protein previously reported to be involved in the biosynthesis of aromatic aminoacids in Euglena. Cells adapted to N-(phosphonomethyl)glycine excreted shikimate and shikimate 3-phosphate into the medium; the amounts depended on the actual concentration of the herbicide. Two-dimensional gel electrophoresis and determination of 5-enolpyruvylshikimate-3-phosphate synthaseactivity in crude extracts, as well as after separation by non-denaturing gel electrophoresis, revealedthat the overproduction of the enzyme in adapted cells correlates with the accumulation of a 59-kDaprotein. Overproduction of this 59-kDa protein resulted from a selectively increased level of a mRNAcoding for a 64.5-kDa polypeptide which appeared in adapted cells, as shown by cell-free translation inthe wheat germ system. In contrast to this quantitative, adaptive type of tolerance, the secondmechanism causing tolerance to N-(phosphonomethyl)glycine in the Euglenacell line NR 6/50 wasprobably related to qualitatively altered 5-enolpyruvylshikimate-3-phosphate synthase, which could not

be inhibited by even 2 mM N-(phosphonomethyl)glycine in vitro. In agreement with this observation,the putatively mutated cell line excreted neither shikimate nor shikimate 3-phosphate into the growthmedium containing N-(phosphonomethyl)glycine, even if cultivated in the presence of 20 mM or 50 mMN-(phosphonomethyl)glycine. (Switzerland).

35. Reinbothe, S., B. Ortel, and B. Parthier. 1993. Overproduction by gene amplification of themultifunctional arom protein confers glyphosate tolerance to a plastid-free mutant of Euglenagraci l is. Molecular and Gen. Genetics 239 , no. 3 : 416-24 .

Cells of the plastid-free mutant line of Euglena gracilisvar.bacillaris, W sub (10)BSmL, can beadapted to glyphosate (N-(phosphonomethyl)- glycine) by gradually increasing the concentration of theherbicide in the culture medium. The molecular basis of glyphosate tolerance is the selective ca. tenfold overproduction of the multifunctional arom protein catalyzing steps 2-6 in the pre-chorismatepathway. Further evidence for an involvement of the multifunctional arom protein is aromatic amino

acid synthesis in the plastid-free W sub(10)BSmL cells was obtained by Northern hybridization withAR01-, aroA-, aroL- and aroE- specific Saccharomyces cerevisiaegeneprobes encoding the entirearom protein or parts of the EPSP synthase, shikimate:NADP super(+) oxidoreductase and shikimatekinase domains, respectively. Overproduction in adapted relative to control cells of 5.3 kb transcriptthat cross-hybridized with all of the different probes could be demonstrated. The elevated content ofthe arom transcript correlated with a selective amplification of two out of five genomic sequences thathybridized with the S. cerevisiae) AR01 gene probe in Southern blots. One of the amplified genomicfragments is assumed to encode the previously identified monofunctional 59 kDa EPSP synthase,which is thought to be an organellar protein, that accumulates to a certain extent in its enzymaticallyactive precursor form of 64.5 kDa in the plastid free W sub(10)BSmL cells. (Switzerland).

36. Reynolds, P. E., J. C. Scrivener, L. B. Holtby, and P. D. Kingsbury. 1989. A summary ofCarnat ion Creek herbicide study r esults. Proceedings of the Carnation Creek Herbicide

Workshop. Forest Resource Development Agreement, B.C. Ministry of Forests, ForestryCanada, B.C. FRDA Report 063, pp. 322-34.

See Fish Section.

37. . 1993. Review and synthesis of Carnation Creek Herbicide research. The ForestryChronic le 69: 323-30.



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38. Richardson, J. T., R. E. Frans, and R. E. Talbert. 1979. Reactions of Euglena graci l istofluometuron, MSMA, Metribuzin and Glyphosate. Weed Science 27: 619-24.

Investigations were conducted on Euglena gracilisKlebs strain Z to determine the effects offluometuron [1,1-dimethyl-3-(-trifluoro-m-tolyl)urea], MSMA (monosodium methanearsonate),glyphosate [N-(phosphonomethyl)glycine], and metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one] on cell number, chlorophyll content, and photosynthesis. Euglena cell number wasreduced by 65% or more after 48 h with fluometuron levels above 4 x 10-5M. MSMA at 6 x 10-4M

reduced cell number 42% after 144 h exposure. Chlorophyll content was reduced 33 to 80% bymetribuzin levels of 2 x 10-6M or greater, and fluometuron inhibited chlorophyll content by 30% ormore from 4 x 10-6M or greater concentrations. Chlorophyll was reduced 21 to 69% by treatment withglyphosate at 3 x 10-3M, but MSMA appeared to have little effect on chlorophyll except at the highlevel of 6 x 10-4M at 48 h. Photosynthesis was reduced 50% or more with metribuzin levels above 9 x10-7M and with fluometuron above 9 x 10 -5M. MSMA reduced photosynthesis by 20% at the 6 x 10-3

M level, and glyphosate slightly reduced photosynthesis at levels below 1.2 x 10 -4M but slightlystimulated it above that level. Chronic effects (Euglena exposed to herbicides 96 h prior tomeasurement) on photosynthesis indicated a more pronounced reduction from fluometuron than fromshort-term exposure, little change with glyphosate, but less reduction with metribuzin than from short-term exposure. Metribuzin caused increased respiration rates of 100 to 200% after 100 min ofexposure. Respiration was stimulated 20% by glyphosate and relatively unaffected by the othercompounds. Removal of Euglena from metribuzin- and fluometuron-treated media to non-treated

media resulted in increased levels of chlorophyll to near that of the control. These results suggest thatuse of these herbicides is not detrimental to non-target algae if the exposure is not intensive.

39. Sacher, R. M. 1978. Safety of Roundup in the aquatic environment. Proceeding s of the 5thInternat ional Conference on Aquatic Weeds. Wageningen, NL: European Weed Res. Soc. pp.315-21.


40. Scrivener, J. C., and S. Carruthers. 1989. Changes in the invertebrate populations of the mainstream and back channels of Carnation Creek, British Columbia, following spraying with theherbicide Roundup (glyphosate). Proceedings of the Carnation Creek Herbicide Workshop.Forest Resource Development Agreement, B.C. Ministry of Forests, Forestry Canada. FRDAReport 063, pp. 263-72.

Populations of macroinvertebrates were monitored at two sites in the main stream and at siteswith bare mud and mud with rooted vegetation substrates in four tributary swamps. Three tributaryswamps (750trib, 1500trib, 1600trib) and one site in the main stream were influenced by the herbicideROUNDUP (glyphosate) after aerial application. Any impacts from the herbicide were not easilydetectable because macroinvertebrate densities varied with substrate types, with the seasons and withprevious hydrological conditions. In the swamps, densities of organisms on the surface of the substratewas related to stream flow with a cubic polynomial (R2= 0.45). Density maxima occurred duringmedian flows, while density minima occurred during periods with extremes of flow. During periods offreshet, densities in the treated swamp were half those of the untreated swamp.

41. Servize, J. A., R. W. Gordon, and D. W. Martens. 1987. Acute toxicity of Garlon 4 and Roundupherbicides to Salmon, Daphnia, and Trout. Bul let in of Environmental Contaminat ion andToxicology 39: 15-22.

See Fish Section.

42. Shindo, N., Y. Yamamoto, M. Ohyama, and A. Murakami. 1986. Effect of several herbicidesagainst microalgae. Mei ji Daigaku Nogakubu Kenkyu Hoko ku 71: 918.

Growth inhibitor effects of 6 herbicides on microalgae, e.g.Anabaena cylindrica,Chlamydomonas reinhardti, and Cyclotellasp., were investigated. The growth and photosynthesis of themicroalgae were inhibited by Me 3,4-dichlorophenylcarbamate, 1,3-dimethyll(5-trifluoromethyl-1,3,4-thiadiazol-2-yl) urea, or oxadiazon at the 10 ppm level, but not by 2,4-D or NaCl03. Glyphosate hadlittle effect on respiration at 30 ppm, but slightly reduced photosynthesis. (Japan).


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43. Simenstad, C. A., J. R. Cordell, L. Tear, L. A. Weitkamp, F. L. Paveglio, K. M. Kilbridge, K. L.Fresh, and C. E. Grue. 1996. Use of Rodeo and X-77 spreader to control smooth cordgrass(Spart ina alternif lor a) in a southwestern Washington estuary: 2. Effects on benthic microfloraand invertebrates. Environmental Toxicology and Chemist ry 15 , no. 6 : 969-78 .

In August 1992, we conducted an intensive short-term (within 119 d) experiment in southernWillapa Bay, Washington, to evaluate the potential effects on mudflat benthic communities of herbicidecontrol of smooth cordgrass, Spartina alternifloraLoisel. A mixture of glyphosate (Rodeo; 4.7 L/ha) andan associated surfactant, alkylarylpolyoxyethylene (AAPOE, X-77 Spreader; 1 L/ha) was appliedaerially to three mudflat sites with invasive S. alterniflora. Sediment structure (grain size), edaphicmicroalgal biomass (chlorophyll a), and densities of benthic and epibenthic meiofauna and benthicmacrofauna were sampled systematically in treated and adjacent control (untreated) plots 1 d before,immediately after, and 1, 14, 28, 119 d after spraying. These mudflat biota showed no definitivedifferences in population trends that would indicate acute responses to the herbicide and surfactantapplications over the 119-d duration of the experiment. Two-way ANOVA tests of differences in slopeof linear regressions of mean plot microalgal biomass and invertebrate density of 19 taxa groups orspecies testing short-term (2 weeks) and long-term (17 weeks) trends in response to the experimentaltreatment tests indicated no significant (p lt 0.1) treatment and only three site effects. Naturalvariability in the standing stocks (in the case of benthic microalgae) or densities (invertebrates) of mostof the 19 indicator taxa prior to spray application was sufficiently high within and between treatmentand control plots and among sites to preclude strong inferential tests of acute effects. Although

differences in mudflat habitats (e.g., tidal elevation, sediment structure) inherent in the sites prior totreatment affect the power of our ability to test direct effects, there were no indications of either short-or long-term effects on the mudflat community of aerially applying this concentration of herbicide andsurfactant. This study did not explicitly address either sublethal or indirect ecological effects, such asassociated with an observed decrease in the exotic eelgrass Zostera japonica, which might appear as alonger-term, more subtle response by the mudflat community.

44. Solberg, K. L., and K. F. Higgins. 1993. Effects of glyphosate herbicide on cattails,invertebrates, and waterfowl in South Dakota wetlands. Wildl i fe Society Bullet in 21 : 299-307 .

See Bird Section.

45. Sullivan, D. S., T. P. Sullivan, and T. Bisalputra. 1981. Effects of Roundup herbicide on diatompopulations in the aquatic environment of a coastal forest. Bul let in of Environmental

Contaminat ion and Toxicology 26: 91-96.(*) This paper reports the effects of RoundupRherbicide (MON 02l39) on diatom populations inseveral field experiments at the University of British Columbia Research Forest, Maple Ridge, B.C.,Canada. A 20-year old Douglas fir plantation received an aerial application of RoundupRherbicide atthe recommended rate of 2.2 kg a.i./ha. Sediment samples and slides available for colonization byalgae were used to assess the effects of this herbicide on the phytoplankton of a stream and pond. Inanother stream RoundupRwas manually applied at field, l0x and 100x field doses and colonizationslides were used to assess toxicity to phytoplankton. It was concluded that variations in abundance ofdiatoms observed in the ponds and streams were mainly determined by habitat and seasonal factorsrather than the aerial or manual application of herbicide.

46. Swinehart, J. H., and M. A. Cheney. 1987. Interactions of organic pollutants with gills of thebivalve molluscs Anodo nta cal i forniens isand Myt i lus c al ifornianusuptake and effect on

membrane fluxes II. Comparative Biochemistry and Physiology C. Comparat ive Pharmacologyand Toxicology 88: 293-300.

The uptakes of 2,4,5-T, glyphosate, parathion, paranitrophenol, naphthalene, glycine, andinulin by gills of the bivalve molluscsAnodonta californiensis(freshwater) and Mytilus californianus(marine) show non-polar compounds are taken up to a greater extent than polar compounds exceptwhere active transport occurs. The uptake of glycine by M. californianusis reduced by pollutantscontaining complexing functional groups but not by non-polar compounds. The uptake of parathionalters the polyphosphate-inorganic phosphate balance in M. californianus. The uptakes of pollutantsparallel their toxicities toward rats.


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47. Thomas, M. W., B. M. Judy, W. R. Lower, G. F. Krause, and W. W. Sutton. 1989. Time-dependenttoxicity assessment of herbicide contaminated soil using the green alga Selenastrumcapricornutum. In: Plants for Toxicity Assessm ent.W. Wang, J. W. Gorsuch, W. R. Lower(editors). pp. 235-54.

Bioassays with S. capricornutumwere performed on filtered eluates from a clay loam soiltreated 1 h-10 d beforehand with 6 herbicides (glyphosate, imazapyr, triclopyr, picloram, 2,4-D andhexazinone) at recommended rates. The 96-h EC50 (effective concn) values indicated growthinhibition (relative to control sample) for all treatments when assayed 1 h after herbicide application.

Algal EC50 values of +100 (control), +27.3 (glyphosate), -20.4 (imazapyr), -22.4 (triclopyr), -49.4(picloram + 2,4-D) and -100 (hexazinone) were obtained. Assays conducted 10 d after herbicideapplication to soil revealed substantially reduced toxicity. A slight reduction in toxicity was noted fortriclopyr and picloram + 2,4-D, and no change was observed with hexazinone. When the herbicideswere applied to water, the following 96-h EC50 (in microg/ml) were obtained: 5300-5500 (imazapyr),5000 (picloram + 2,4-D), 5000 (triclopyr), 2600 (glyphosate) and 1.2-2.5 (hexazinone).

48. Tooby, T. E. 1985. Fate and biological consequences of glyphosate in the aquatic environment.In: The Herbicide Glypho sate. E. Grossbard, and D. Atkinson, 206-17. London: Butterworths.


49. Trotter, D. M., M. P. Wong, and R. A. Kent. 1990. Canadian water quali ty guidel ines for

glyphosate., Water Quality Branch, Inland Waters Directorate, Environment Canada, Ottawa,Ontario. 27 p.


50. U.S.D.I. 1981. Fisheries and Wildl i fe Research 1980. U.S. Department of the Interior, Fish andWildlife Service. 201 p.

See Fish Section.

51. Wimberely, D. N., and S. G. Berk. 1991. Microplate analysis of dehydrogenase activity inprotozoa a rapid aquatic toxicity assay. General Meeting of the American Society forMic rob io logy 91:321.

52. Wood, D. E. 1996. "Evaluation of the herbicides glyphosate and fluridone for use in waterfowl

management impoundments. " M.Sc. thesis , University of Georgia, Athens.See Birds Section.


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1. Arshad, M. A., K. S. Gill, and G. R. Coy. Barley, canola, and weed growth with decreasing tillagein a cold, semiarid climate. Agronomy Journa l 87, no. 1 : 49-55 .

Conventional tillage systems are reported to cause soil degradation, yet appropriate

conservation tillage practices have not been developed for cold regions of the northern CanadianPrairies. Effects of conventional, reduced, and zero tillage systems (CT, RT, and ZT) on the growth ofdryland spring barley (Hordeum vulgareL.), canola (Brassica campestrisL.), and weeds were studiedon a clay soil (Natriboralf) near Rycroft in northern Alberta. Each crop-tillage combination was fixed inspace from 1989 through 1991. Each season, the CT plots were tilled once in the preceding fall andtwice in the spring prior to seeding; the RT plots were tilled once prior to seeding in the spring; the ZTplots received a preseeding glyphosate (N- (phosphonomethyl) glycine) application in the spring. Cropresidue in ZT was spread evenly by harrowing in the spring just prior to seeding. The 1991 availableNO-3-N, NH-4-N, and P in soil or total plant N and P were unaffected by tillage, except that NO-3-Nwas lower under ZT canola. No consistent effect of tillage was detected on total soil moisture, exceptfor lower moisture in the 0- to 10-cm depth under CT in dry periods. As the study progressed, therewas a trend of increased weed population response to tillage, relatively greater weed density under ZT,and a shift in species composition. Mean barley total dry matter (TDM) yield was 3.37, 3.09, and 2.93

mg/ha and grain yield was 1.59, 1.41, and 1.35 mg/ha under RT, ZT, and CT, respectively. Meancanola TDM yield was 2.92, 2.36, and 2.12 mg/ha and grain yield was 0.84, 0.66, and 0.59 mg/ha,under RT, CT, and ZT, respectively. In most cases, however, tillage effects on mean crop yields werenonsignificant (P ltoreq 0.05). Overall, RT was considered to be agronomically and environmentallydesirable, due to somewhat better crop yield than ET or ZT systems and two fewer cultivations thanCT.

2. Astiz, S., H. Alvarez, and A. Sladeckova. Indirect effects of glyphosate application in the controlof Salvinia auriculatain experimental systems. Trav. Asso c. Int. Limno l. Theor. Appl. 25 , no. 4:2064-67.(Spain).

3. Becker, M., G. Levy, and Y. Lefevre. 1996. Radial growth of mature pedunculate and sessileoaks in response to drainage, fertilization and weeding on acid pseudogley soils. Annales DesSciences For estieres (Paris) 53, no. 2-3 : 585-94 .

In northeastern France, forest soils on old alluvial terraces are generally unfavourable, stronglyacid and often characterized by superficial temporary water tables. In this case, the ground vegetationis dominated by a dense cover of Carex brazoideson the moderately hydromorphic soils (Carexsite) orMolinia caeruleaon the strongly hydromorphic soils (Moliniasite). Both pedunculate and sessile oaksare present in the Molinia site, and practically only pedunculate oak in the Carexsite. The experimentaimed at quantifying the radial growth response of mature oaks to various silvicultural interventions. Itincluded i) ditching in order to drain the soils (in 1974), ii) herbicide application (glyphosate; in 1981),and iii) fertilization (P, K, Ca and Mg in 1982; N in 1982 and 1985). A dendrochronologicalinvestigation was performed on 620 adult oaks from 60 to 200 years old, which were subjected to thesetreatments, alone or in combination. The results refer to basal area increment by comparison withcontrol trees. The effect of drainage depended on the site type, the oak species and the age of thetrees. Drainage had practically no effect in the Carexsite. In the Moliniasite, the effect was positive(+20%) for the young (ltoreq 110 years old) sessile oaks only. It became even depressive (-15%) forthe old (gt 110 years old) pedunculate oaks. The effect of weeding differed according to the site type,the age of the trees and the drainage modality. Whatever the drainage modality, the effect wasdepressive (-13%) for the young trees and nonsignificant for the old ones in the Carexsite. There wasa positive interaction between weeding and drainage in the Moliniasite, in the old trees (+22%) as wellas in the young ones (+17%), whereas weeding alone had a negative effect (-5%). The effect offertilization was strongly beneficial (about +20%) in all cases, without any interaction of site type ordrainage. However, the time dynamics of this effect was different according to the age of the trees: i)the mean effect was lower in the young trees (+15%), but it was still high when the trees were cored(1991); ii) it was higher in the old trees (+25%), but tended to vanish about 9 years after fertilizing. For


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analyzing the results related to drainage and weeding, we needed to take into account the competitionfor the mineral nutrients between trees and weeds, as well as the water table depth in the soil, whichdepends on the evapotranspiration of the whole vegetation cover including trees and ground layer.(France) .

4. Bell, F. W., R. A. Lautenschlager, R. G. Wagner, D. G. Pitt, J. W. Hawkins, and K. R. Ride. 1997.Motor-manual, mechanical, and herbicide release affect early successional vegetation in

northwestern Ontario. Forestry Chronic le73: (In press) .Cover and height of vegetation before and one growing season after: 1) motor-manual cutting,

2) mechanical brush cutting (Silvana Selective/Ford Versatile), 3) aerial application of Release (a.i.triclopyr) herbicide, 4) aerial application of Vision (a.i. glyphosate) herbicide, and 5) control (notreatment) were quantified. Multivariate analysis permitted the study of vegetation response as awhole, while accounting for correlations that exist among the individual vegetation groups. Univariateanalysis was used to study the responses of individual vegetation groups. Although no pre-treatmentdifferences in percent cover were observed (P =0.128), deciduous tree, shrub, forb, grass, and sedgegroups responded differently to the treatments after one growing season (P < 0.018). Post-treatmentcover of deciduous tree and shrub groups was lower in herbicide treated plots than in cut plots. Forb,grass and sedge covers varied greatly among treatments. Brush saw and Silvana Selective treatmentsdecreased cover of deciduous trees. Release decreased cover of deciduous trees and shrubs.Vision decreased cover of deciduous trees, shrubs and ferns. Cover of all vegetation groups

increased on the untreated control. Among the conifer release treatments examined, Vision reducedwoody and herbaceous vegetation most.

5. Blackshaw, R. E., and C. W. Lindwall. 1995. Management systems for conservation fallow on thesouthern Canadian prairies. Canadian Jour nal of Soil Science 75, no. 1 : 93-99 .

6. . 1995. Species, herbicide and tillage effects on surface crop residue cover during fallow.Canadian Jour nal of Soil Science 75, no. 4 : 559-65 .

Fallow continues to be a common agronomic practice on the Canadian prairies but it has beenassociated with increased soil erosion. Risk of fallow erosion can be reduced by maintaining adequatelevels of crop residue on the soil surface. Field experiments were conducted at Lethbridge, Albertafrom 1991 to 1993 to determine if commonly grown prairie crops differ in their rates of crop residuedegradation during fallow and to assess the effect of herbicides and wide-blade tillage on loss of crop

residues. The ranking of crop residue losses during fallow was lentil gt canola gt rye gt barley gt wheatgt flax. High N content in residues usually increased the rate of biomass loss. Flax straw, perhapsbecause of its high lignin content, did not follow this pattern and was the most persistent of all cropresidues. Up to three applications of the herbicides, glyphosate, paraquat and 2,4-D, at recommendedrates did not alter field degradation of any of these crops. These herbicides maintained greateramounts of anchored and total surface crop residues than wide-blade tillage during both fallowseasons. Results are discussed in terms of crops grown before fallow, weed control during fallow, andmaintenance of sufficient surface plant residues to reduce the risk of soil erosion.

7. Blixt, D. C. 1993. "Effects of glyphosate-induced habitat alteration on birds, using wetlands."M.S. Thesis , North Dakota State University. Fargo, ND. 127 pp.

See Birds Section.

8. Bogart, J. P., R. A. Lautenschlager, and F. W. Bell. 1995. Effects of alternat ive vegetat ionmanagement t reatments on amphibians and rept i les in the Fall ingsnow Ecosystem.Fallingsnow Ecosystem Workshop. Program and Abstracts. Ministry of Natural Resources,Ontario VMAP. pp. 32-33.

(*) The effects of different forest release treatments (brush saws, Silvana Selective, Release,Vision, and control) on amphibians and reptiles were examined as part of the Fallingsnow EcosystemProject. No treatment related population changes have been observed to date. Because of the largearea, low herpetofaunal diversity, and non-random distribution of amphibians and reptiles, it was notpossible to estimate population densities in the study sites using mark-recapture methods. More


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realistic monitoring techniques, such as estimations of recruitment, age structure, comparativesurvivorship, and modified levels of heterozygosity, are therefore presently being tested.

9. Boyd, R. S., J. D. Freeman, J. H. Miller, and M. B. Edwards. 1995. Forest herbicide influences onfloristic diversity seven years after broadcast pine release treatments in central Georgia, USA.New Forests 10, no. 1 : 17-37 .

Maintenance of biodiversity is becoming a goal of forest management. This study determined

effects of broadcast pine release herbicide treatments on plant species richness, diversity, andstructural proportions seven years after treatment. Three study blocks were established in centralGeorgia. Plots 0.6-0.8 ha in size were planted to loblolly pine (Pinus taedaL.) in the winter of 1982-83and then treated with imazapyr (Arsenal), glyphosate (Roundup), and hexazinone (Velpar L. andPronone 10G) in 1985. In 1992, overstory and understory (lt 1.5 m height) layers were examinedutilizing stem and rootstock counts and basal area of overstory species and cover of understoryspecies. ANOVAs were used to test for significance using a randomized complete block model. Wefound no effect of treatments on species richness. Diversity, measured separately for overstory andunderstory layers by Shannon-Wiener and Simpson indices, also was not influenced significantly bytreatments. Arsenal significantly decreased Diospyros virginiana L. and increased Rubus argutusLinkand legumes. Hexazinone treatments generally decreased Quercus nigraL., and Roundup significantlyreduced Vacciniumspp. compared to the Check. We concluded that herbicide release treatments didnot decrease overstory or understory plant species richness and diversity seven years post-treatment.

10. Caffrey, J. M. 1993. Plant management as an integrated part of Ireland's aquatic resources.Hydroecological Appl icat ions5, no. 1 : 77-96 .

This paper outlines the nature and extent of the more important weed problems in Irish aquaticsituations and describes a range of control strategies that may be adopted to rehabilitate these habitatsand to enable their exploitation by a diversity of user groups. In certain instances paucity of aquaticvegetation presents problems, including bankside destabilization and in channel siltation. Reedtransplantation trials have been conducted in denuded Irish canals in an effort to rehabilitate thesehabitats and the results from these are presented. Weed control procedures generally embrace fourbroad categories. These are mechanical, chemical, environmental and biological control. Of theseonly biological control is not widely adopted in Ireland. The effects that these procedures have onspecific weeds were quantitatively investigated at a number of aquatic situations throughout thecountry. Results from experiments among a diversity of aquatic plant species and involving the use of

mechanical weed cutting apparatus show that, unless the plant is cut to a depth at which lightpenetration is significantly diminished, rapid regrowth will occur and higher standing crops than mightotherwise be expected may be recorded. Experimentation with a small number of herbicides hasrevealed that, when used with discrimination, these provide effective weed control, with little or nodetrimental effect to the aquatic ecosystem. Results from trials with dichlobaenil and glyphosate onaquatic and riparian species are presented. The effect that shading has on macrophyte biomass andthe effect that rotted barley straw has on algal growths in watercourses is also described.

11. Cole, E. C. 1996. Managing for mature habitat in production forests of western Oregon andWashington. Weed Technolo gy 10 : 422-28 .

Standard timber management practices in the Pacific Northwest result in stands which oftenvary from unmanaged stands in structure and composition. Forest and wildlife managers haveidentified a deficit of stands in the mature (> 100-year-old) age class that contain certain desirable

wildlife habitat features. Techniques are being developed that would increase the likelihood thatmanaged stands can produce these characteristics. The key desirable components in these standsinclude large (> 75 cm diam breast height) conifer trees, snags, coarse woody debris, and understorystructure, including regeneration. Vegetation management techniques can facilitate development ofthese components within stands. Thinning the overstory, underplanting shade-tolerant species, andcreating snags and coarse woody debris can be accomplished within a production forest. Maintainingshade-intolerant species requires a higher level of disturbance and canopy opening than needed forshade-tolerant species. Treatments which remove competition from shrubs and herbaceous plantsmay be necessary to insure growth and survival of understory regeneration. Injection of differentherbicides into low-grade conifers may yield different types of snags in comparison to girdling or


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topping. Although much of the understory may be eliminated during future thinnings and final harvest,some of the structure will remain and could be carried over into the next rotation along with snags andlarge coarse woody debris. These treatments are expected to enhance mature habitats in present andfuture cycles with minimum impact on yield.

12. Cole, E. C., W. C. McComb, M. Newton, C. L. Chambers, and J. P. Leeming. 1995. Response ofsmall mammal and amphibian capture rates to clearcutting, burning, and glyphosate

application in the Oregon coast range. Second Internat ional Conference on For est Vegetat ionManagement. Rotorua, New Zealand. R. E. Gaskin, and J. A. Zabkiewicz, (compilers). FRIBulletin No. 192. pp. 155-57.

See Mammals Section.

13. . 1997. Response of amphibians to clearcutting, burning, and glyphosate application inthe Oregon coast range. Journal o f Wi ldl i fe Management(In press) .

We sampled amphibians on 3 red alder (Alnus rubra) sites 1 year before and 1 and 2 yearsafter the following treatments were applied to each site: (1) control (uncut), (2) clearcut and broadcastburned, and (3) clearcut, broadcast burned, and then sprayed with the herbicide glyphosate. All sitesincluded uncut riparian buffer strips. For 3 of the 6 species with >20 captures in pitfall traps, we didnot detect changes in capture rates after clearcutting. Capture rates of ensatina salamanders (Ensatinaeschscholtzii) and Pacific giant salamanders (Dicamptodon tenebrosus) decreased after logging.

Capture rates of western redback salamanders (Plethodon vehiculum) increased the first year afterlogging, probably because the salamanders sheltered in pitfalls, but effects on populations wereunclear. Logging did not significantly alter capture rates of rough-skin newts (Taricha granulosa),Dunns salamanders (P. dunni), and red-legged frogs (Rana aurora). Planning the location and timingof clearcuts or other silvicultural practices over a landscape and retaining riparian buffer strips may benecessary to ensure long-term persistence of Pacific giant salamanders. We did not detect any effectsof herbicide spraying on capture rates. Capture rates for rough-skin newts and red legged frogs werehigher in uncut red alder stands than in Douglas-fir (Pseudotsuga menziesii) stands sampled in otherpublished studies, an indication that, when red alder stands are converted to Douglas-fir, some trees ofthe former should be left adjacent to streams to provide habitat for these species and other hardwoodassociates.

14. Cole, E. C., W. C. McComb, M. Newton, J. P. Leeming, and C. L. Chambers. 1997. Response of

small mammals to clearcutting, burning, and glyphosate application in the Oregon coast range.Journal o f Wi ldl i fe Management (submitted) .


15. Edwards, M. B., and B. D. Shiver. 1993. Can forest site preparation benefit stand-level diversity?Proceeding s of the Internat ion al Conference on Forest Vegetat ion and Management - Ecolog y,Pract ice, and Policy. D. H. Gjerstad (compiler). Auburn University. pp. 120-123.

... A silvicultural perspective is presented which includes a new forest stand-level index fordiversity calculations, Silviculture Diversity Index (SDI). ... The SDI incorporates the herbaceous aswell as the woody components and presents a more complete description of stand level diversity[including wildlife foods]. The new diversity index as well as ... traditional indices are calculated for 10different site preparation treatments [a control, an intensive mechanical treatment, and 8 chemicaltreatments] in the Georgia Piedmont. Results indicate that only two treatments decreased biodiversity

after 5 years. The greatest decrease was found in the control - an indication that silvicultural practicescan be beneficial in creating and maintaining diversity in young pine stands. All but one ... treatmentactually increased biodiversity as compared to initial conditions.

16. Eggestad, M., E. Enge, O. Hjeljord, and V. Sahlgaard. 1988. Glyphosate application in forest-ecological aspects. VIII. The effect on Black Grouse (Tetrao tetrix) summer habitat.Scandinavian Jou rnal of Forest Research 3: 129-35.

See Birds Section.


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17. Ferm, A., J. Hytonen, S. Lilja, and P. Jylha. 1994. Effects of weed control on the early growth ofBetual pendulaseedlings established on an agricultural field. Scandinav ian Jou rnal of ForestResearch 9, no. 4 : 347-59 .

Various herbicides (glyphosate, sethoxydim, pendimethalin, chlorthiamid, dichlobenil,terbuthylazine) as well as particle board mulch and a cover crop (clover, Trifolium repens) werecompared during the first two post-planting years as weed control means in a silver birch (Betula

pendula) plantation established on agricultural soil in southern Finland. Chlorthiamid, dichlobaenil andterbuthylazin exhibited good weed control for two years and also increased the height growth of theseedlings by 40-50 cm and much greater relative increase in the leaf area and volume as compared tountreated control plots. Weed control had a significant effect on the foliar nutrient concentrations ofbirch, particularly that of N. As the amount of weed vegetation increased, foliar N, P (second year), K,Cu and B decreased and, respectively, foliar P (first year), Ca and Mg increased. Vegetation controlalso had a great indirect influence on the state of health of the seedlings. Incidences of vole damageand bark necrosis disease were associated with a high cover-percentage of weeds, particularly ofclover which is much favored by voles. Particle board mulch seemed to increase vole damage byproviding shelter for the voles. The competition by weeds for nutrients, and probably also for water,was much more important than their competition for light. Use of mulch and a cover crop did notreduce root competition as effectively as did the best herbicides. (Finland) .

18. Flickinger, E. L., and G. W. Pendleton. 1994. Bird use of agricultural fields under reduced and

conventional tillage in the Texas Panhandle. Wildl i fe Society Bullet in 22 : 34-42 .`We conducted bird surveys in reduced-tillage and conventional tillage fields in spring,

summer, fall, and winter from 1987 to 1991 in the Texas Panhandle. Eastern meadowlarks, longspurs,and savannah sparrows were more common in reduced-tillage (sorghum and wheat stubble) fields thanin conventionally tilled (plowed) fields in at least 1 season. Other species also had patterns suggestiveof greater abundance in reduced-tillage fields. Horned larks, which prefer habitat with sparsevegetation, were more abundant in plowed fields in all seasons except summer. Bird diversity wasgreater in reduced-tillage fields than in conventionally tilled fields in summer. Cover density and heightwere greater in reduced-tillage fields in all seasons except spring. Cover density and height rather thancover composition (e.g., grain stubble or live plants) seemed to be the important factors affecting birddistribution. Patterns of bird abundance between sorghum and wheat stubble fields also weredependent on cover. Herbicide use was not greater in reduced-tillage fields than in conventionally tilledfields. Reduced-tillage agriculture for sorghum and wheat farming should be encouraged in the

southern Great Plains as a means of improving the attractiveness of agricultural land to many birdspecies.

19. Freedman, B. 1991. Controversy over the use of herbicides in forestry, with particular referenceto glyphosate usage. Journal o f Environm ental Science and Heal th C8: 277-86.


20. Gardner, S. C., and C. E. Grue. 1996. Effects of Rodeo registered and Garlon registered 3A onnontarget wetland species in central Washington. Environmental Toxicology and Chemist ry15, no. 4: 441-51 .

See Fish Section.

21. Gordon, A. M., J. A. Simpson, and P. A. Williams. 1995. Six-year response of red oak seedlings

planted under a shelterwood in central Ontario. Canadian Journ al of Forest Research 25, no. 4: 603-13 .

This study investigated the potential for underplanting 1+0 and 1+1 northern red oak (QuercusrubraL.) in conjunction with a two-cut shelterwood harvest of a low-quality, ridgetop, tolerant hardwoodstand in central Ontario. Growth patterns were followed for 6 years; herbicide (glyphosate) applicationand prescribed fire (two burns, 3 years apart) were used as competition control measures in anexperimental design that tested all possible combinations of stock type, competition control, andclipping 2 years after planting. Six years after outplanting the mean height attained across alltreatments for 1+0 stock was 76 cm and for 1+1 stock, almost 90 cm. Depending upon treatment, someindividuals were almost 3 m tall. In the presence of heavy deer (Odocoileus virginianusZimmerman)


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browsing, competition control of any type does not appear to be warranted (i.e., control treatment). Thegeneral technique for establishment of oak in this manner appears to be logical for these siteconditions, but further investigations necessary to address the direct impact of browsing pressure onseedling growth and the potential for similar silvicultural prescriptions on more marginal oak sites.

22. Graves, D. H., and J. M. Ringe. 1993. European black alder survival and growth responses toherbicide treatment on an eastern Kentucky vegetated coal surface mine excess spoil area after

three and eight years. Internat ional Journal o f Surface Mining and Reclamat ion 7, no. 1 : 37-40.

A research area was established on a surface coal mine in eastern Kentucky in 1982 to test theeffects of eight herbicide treatments, mechanical scalping and no treatment on the long term survivaland growth of European black alder (Alnus glutinosa). After eight years, three treatments (mechanicalscalping and glyphosate applied simultaneously with napropamide prior to planting or by usingnapropamide as a post planting treatment after initial applications of glyphosate as a pre-planttreatment) were superior to one or more of the other treatments for all eight parameters tested andwere indifferent to each other. If the parameter, percent growth change over time, was not consideredan important factor in establishing this species, no treatment was significantly different from the control.Such results indicate factors other than biological responses should be considered when selecting awoody vegetation establishment scheme on surface coal mine excess spoil areas with existingherbaceous cover.

23. Grilz, P. L., and J. T. Romo. 1995. Management considerations for controlling smooth brome infescue prairie. Natural Areas Journal 15, no. 2 : 148-56 .

Smooth brome (Bromus inermisLeyss.), an introduced perennial grass, is an aggressiveinvader of prairie dominated by plains rough fescue (Festuca altaicaTrin. subsp. hallii [Vasey] Harms).We (1) compared richness and density of plant species in brome and fescue stands that were unburnedor burned in spring or fall; (2) determined the effects of wick application of a 33% glyphosate solution,applied when smooth brome was in the boot stage, on the density of brome and native flora inunburned plots and plots burned in spring or fall, and; (3) determined the composition of the seedbankfor its potential contribution to natural revegetation following the control of smooth brome. Stemdensities of native species and plains rough fescue were about two- and fivefold greater, respectively,in fescue plots than in brome plots. Species richness was generally slightly greater in fescue than inbrome plots. Burning had no significant effect on stem density of smooth brome. At one site, changes

in the density of smooth brome were affected by the interacting effects of burn treatments andglyphosate application. Glyphosate eliminated brome in the spring burn plots and reduced densities 76and 50% (SE plus or minus 6.4) in the fall burn and unburned plots, respectively. At a second site,smooth brome densities were reduced by glyphosate but not by burn treatments. There was, however,a trend for greater reduction of smooth brome with glyphosate application in the spring burn (98%) thanin the fall burn (40%) and unburned (56%) plots (SE plus or minus 15.5). Glyphosate reduced thedensity of native graminoids 91% (SE plus or minus 10.0), but plains rough fescue and native forbswere not affected. Twenty-three species emerged from the seedbank in fescue plots, whereas twentyemerged from soils collected in brome plots. The total number of seedlings emerging from theseedbank was similar in brome and fescue plots, averaging 1794/m2and 2078/m2(SE plus or minus252), respectively. The proportion of seedlings emerging was lower for native graminoids (33 vs. 41%,SE plus or minus 2) and greater for native forbs (56 vs. 48%, SE plus or minus 3) in brome ascompared to fescue plots. Smooth brome seedlings emerged only from soils collected in brome plots,

averaging 3/m

2

. These studies indicate that excellent control of smooth brome can be achieved withspring burning followed by wick application of glyphosate; however, native species were also reducedby glyphosate. Additional glyphosate applications will be required for complete control of smoothbrome. The number of seeds of native species in the soil in smooth brome stands approximates that instands of plains rough fescue, suggesting that there is an adequate seedbank for natural recovery ofvegetation following control of smooth brome.

24. Gutierrez, E., F. Arreguin, R. Huerto, and P. Saldana. 1994. Aquatic weed control. Internat ionalJou rnal of Water Resource Development10, no. 3: 291-312.

See Plant and Soil Residues Section.


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25. Gutierrez, L. E. 1993. Effect of glyphosate on different densities of water hyacinth. Journal ofAquat ic Plant Management 31 : 255-57 .

Water hyacinth (Eichhornia crassipes) is a problem in rivers and reservoirs in Mexico andappropriate control methods need to be evaluated. The phytotoxic effects of the herbicide glyphosatewere determined on water hyacinth in the reservoir Endho, State of Hidalgo, Mexico. Duplicate 1 m2

areas initially containing 10, 20, 30, and 40 kg/m2densities of water hyacinth were randomlyestablished. After a 2 week acclimatization period, two doses of glyphosate (Rodeo at 5 l/ha and 7

l/ha) were applied to the plots and plots were evaluated at 9, 19, 33, 51, 72 and 94 days aftertreatment. Glyphosate at 5 l/ha (2.38 kg/ha acid) effectively controlled densities of 10 and 20 kg/m2in51 days. At higher plant densities (30 and 40 kg/m2), a second application of glyphosate at day 51 of 2l/ha (0.95 kg/ha) was necessary to achieve plant control. The response of the plants indicated that asecond application 20 to 30 days after the first would provide good results in high density areas.(Mexico) .

26. Harrington, T. B., R. G. Wagner, S. R. Radosevich, and J. D. Walstad. 1995. Interspecificcompetition and herbicide injury influence 10-year response of coastal Douglas-fir andassociated vegetation to release treatments. Forest Ecology and Management 76 : 55-67 .

Responses of competing vegetation and planted Douglas-fir (Pseudotsuga menziesii(Mirb.)Franco var. menziesii) were studied for 10 years after six herbicide and manual release treatments inthe Washington and Oregon Coast Ranges. Research objectives were to quantify regional, long-term

responses of vegetation to various levels of competition, light and soil water availability, and intensityversus importance of factors influencing Douglas-fir growth. Three treatments reduced shrub coverrelative to the untreated check: triclopyr in year 1, glyphosate in years 1-5, and repeated control (viaseveral herbicide applications) in years 1-10. Reductions in woody cover from glyphosate stimulatedincreases in herb cover in years 3 and 5, while repeated control reduced herb cover in years 1, 2 and 5.Through year 10, Douglas-fir survival (86-99%) varied little among treatments. Visual symptoms ofherbicide injury to Douglas-fir from triclopyr (45% of trees) and glyphosate (17% of trees) wereassociated with 0.1-0.2 m reductions in first-year height. After adjusting for tree size, Douglas-firgrowth in stem basal area 2 years after triclopyr was less than that of the untreated check, suggestingprolonged effects of herbicide injury. Because it sustained low levels of interspecific competition,caused minimal tree injury, and prevented overtopping cover from red alder (Alnus rubraBong.),repeated control was the only treatment in which Douglas-fir size (9.8 m height and 21 cm basaldiameter in year 10) significantly exceeded (P


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with 1 lb ai (active ingredient)/ac of Roundup in August 1979; the remaining 10 ac were unsprayed.The entire 20 ac stand received a shelterwood seed cut the following winter. On treated plots, fern wasreduced from 57% stocking before treatments to 7% 1 yr after treatment; striped maple and beechstocking was reduced by 16% during the same time. By the fourth year after treatment, regenerationstocking of desirable hardwood species had doubled on treated plots but remained unchanged onuntreated control plots. Species diversity was measured by species richness, three diversity indices -Berger-Parker, Margalef, and Shannon, an index-free diversity ordering. Neither the herbicide

treatment nor the shelterwood seed cut had a statistically significant effect on species richness of eitherwoody species or herbaceous species groups. Nor was there a significant effect of treatments onwoody species diversity as measured by the three diversity indices. Index-free diversity orderingshowed: (1) a trend toward increase in less common species on Roundup-treated areas, and (2) thediversity of herbaceous species groups was higher in all 7 yr after treatment with Roundup. Values ofthe three diversity indices were higher for herbaceous species on Roundup-treated subplots for 2 to 7 yrafter treatment. Much of this increase resulted from germination of seedbank grasses, sedges, andRubusspp. with the qualification that long-term and current browsing by deer has impoverished theflora of the Allegheny hardwood forest, diminishing potential treatment effects, the study demonstratedthat Roundup treatment aided desirable regeneration establishment, did not have a negative impact onwoody species or herbaceous species group diversity, and may have increased diversity of herbaceousspecies.

31. Hoy, J. B., D. L. Dahlsten, and P. J. Shea. 1982. The effects of 2,4-D and an alternative material(Glyphosate) used for brushfield rehabilitation on soil arthropod community and litterdecomposition rate., Final Report USAUCB, Research Agreement PSW-81-0026. 34 p.

32. Jackson, N. E. 1996. Chemical control of saltcedar (Tamarix ramosissim a). Proceedings o f theSaltcedar Management Worksh op, Imperial County and UC Davis : University of CaliforniaCooperative Extension. pp. 21-26.

Chemical weed control may be the optimal method for control and removal of salt cedar duringthe establishment of native habitat restoration projects. Roundup, Rodeo, Arsenal, Garlon 3A and 4,and Pathfinder II herbicides are the products most often chosen by managers of native habitatrestoration projects because these herbicides are efficacious and cost-effective, with favorableenvironmental and toxicological properties. Herbicides may be used effectively, within a definedmanagement plan. Individual products may be applied as a foliar treatment by hand or aeriall

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