Glyphosate (Roundup), when applied to the soil usually did not exert any significant effect on the total count of soil fungi after all periods of the experiment except after 6 and 10 weeks where the count was inhibited by the two doses used (1.84, 9.2 mg active ingredient/kg dry soil). When the herbicide was incorporated into the agar medium the count of total fungi, Acremonium strictum and Aspergillus fumigatus was significantly increased by the two doses used and of Penicillium glabrum by the high dose only. However, P. funiculosum was completely eliminated by the high dose. Oxygen consumption in soil treated with glyphosate was significantly inhibited by the high dose after 2 weeks and by the two doses after 6, 8 and 10 weeks. Glyphosate exerted two significant effects of stimulation and inhibition on the rate of the decay of stem segments of three plants at certain treatments of dose and time.

Adkins, S. W., S. Tanpipat, et al. (1998). "The influence of soil moisture content on glyphosate efficacy for the control of annual grasses in fallow land." Weed Research 38(2): 119-127

In order to determine the effects of soil moisture content on the efficacy of glyphosate, field experiments were conducted on three annual grass weeds (Avena fatua L., Urochloa panicoides Beauv. and Echinochloa colona L. (Link)). The soil moisture conditions were as follows: absence of rainfall using a rain-out shelter, natural rainfall and natural rainfall plus irrigation (2.5 cm week-1). These conditions were selected as they are representative of those in winter and summer fallows in the north-east grain region of Australia and had been previously identified by glasshouse experiments to be conditions that influence glyphosate efficacy. As predicted, efficacy of 360 g acid equivalent ha-1 glyphosate when applied to all three species was greatest under the irrigated and normal rainfall conditions and significantly less under the exclusion of rainfall condition. This response was the same for all near-isogenic lines of A. fatua and U. panicoides studied. As mild and severe forms of water stress are common events in the region, it is highly likely that soil moisture level will interfere with efficacy of glyphosate application in summer and winter fallows.

Alferness, P. L. and Y. Iwata (1994). "Determination of glyphosate and (aminomethyl)phosphonic acid in soil, plant and animal matrices, and water by capillary gas chromatography with mass-selective detection." Journal of Agricultural and Food Chemistry 42(12): 2751-2759

A residue method for the determination of glyphosate (N-(phosphonomethyl)glycine, PMG) and its principal metabolite, (aminomethyl)phosphonic acid (AMPA), in soil, crops, animal products, and water was developed. PMG and AMPA were extracted from soil using a mixture of 0.25 M NH-4OH and 0.1 M KH-2PO-4, from crops with water, and from animal products with either 0.1 N HCl or 0.6% acetic acid. Extracts of crops and animal products were cleaned up on a cation exchange column. Soil extracts, purified extracts of crops and animal products, and water samples were directly reacted with a mixture of heptafluorobutanol and trifluoroacetic anhydride. Derivatized analytes were quantified by using capillary gas chromatography and a mass-selective detector operated in the selected-ion-monitoring mode. The limit of quantitation was demonstrated to be as low as 0.01 mg/kg for each analyte. For PMG, the mean recoveries from soil, crops, animal matrices, and water ranged from 90 to 100% with coefficients of variation (CV) ranging from 6 to 14%. For AMPA, the mean recoveries ranged from 89 to 103% with CVs ranging from 8 to 13%.

Alpert, P., F. T. Griggs, et al. (1999). "Riparian forest restoration along large rivers: Initial results from the Sacramento River Project." Restoration Ecology 7(4): 360-368

Restoration of riparian vegetation along large rivers is complicated by the patchiness of the habitat and by conflicts with the societal need to control flooding. The Sacramento River Project, led by The Nature Conservancy in northern California, is testing whether it is possible to restore native forest along a large river without removing flood control. We conducted a post-hoc analysis of monitoring data collected by the project on 1-4-year old plantings of 10 native trees and shrubs at five sites. Two questions of general interest were: Can one identify types of species or sites that are especially suitable for restoration in such riparian habitats? To what degree must sites be treated as mosaics of patches, with different types of patches that are suited to different species? Plant performance as measured by height was better in species of Salicaceae or in species planted as cuttings than in species of other families or in species planted as seedings or seeds. Three within-site factors, land form, soil depth to a buried layer of sand or gravel, and soil texture, affected the growth of several species, indicating that sites do need to be treated as patchy. However, there was little evidence that different species performed better on different types of patches. Instead, areas with deep or fine soils seemed to be favorable for a number of species. Results suggest that it is feasible to re-establish native trees and shrubs along large, regulated rivers, at least at certain sites for an initial period of several years with the aid of weed control and irrigation. Shallowly buried layers or lenses of gravel or sand are a hidden, fine-scale factor that can reduce plant growth on river terraces.

Anonymous (2005). "California Conservation Corps attacks Arundo." Noxious Times 7(3-4): 18 (http://www.cdfa.ca.gov/phpps/ipc/noxioustimes/noxtimes_archives.htm).

Anonymous (2005). "JK International, LLC provides new herbicide delivery system." Noxious Times 7(2): 15 (http://www.cdfa.ca.gov/phpps/ipc/noxioustimes/noxtimes_archives.htm).

Anonymous (2005). "Noxious weed washer - mobile vehicle decontamination unit." Noxious Times 7(3-4): 17 (http://www.cdfa.ca.gov/phpps/ipc/noxioustimes/noxtimes_archives.htm).

Bautista, S. (1998). A Comparison of Two Methods for Controlling Arundo Donax. Arundo and Salt Cedar: The Deadly Duo, A Workshop on Combating the Threat from Arundo and Salt Cedar. C. E. Bell. Ontario, CA, University of California Cooperative Extension, Imperial County: 49-52 (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).

Bautista, S. J. (1994). Riparian habitat, endangered species, and herbicide: cover all the bases during public involvement. Proceedings, annual Forest Vegetation Management Conference. Redding, CA: 166-170

Bell, C. E. (1998). Risks and Effects of Various Control Methods. Arundo and Salt Cedar: The Deadly Duo, A Workshop on Combating the Threat from Arundo and Salt Cedar. C. E. Bell. Ontario, CA, University of California Cooperative Extension, Imperial County: 43-46 (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).

Bell, G. (1997). Ecology and management of Arundo donax, and approaches to riparian habitat restoration in Southern California. Plant Invasions: Studies from North America and Europe. Leiden, The Netherlands, Blackhuys Publishers: 103-113 (http://teamarundo.org/ecology_impacts/arundo_ecology.html).

Boose, A. B. and J. S. Holt (1999). "Environmental effects on asexual reproduction in Arundo donax." Weed research 39(2): 117-127 (http://www.blackwell-synergy.com/links/doi/10.1046/j.1365-3180.1999.00129.x).

Borjesson, E. and L. Torstensson (2000). "New methods for determination of glyphosate and (aminomethyl)phosphonic acid in water and soil." Journal of Chromatography A 886(1-2): 207-216

New methods were developed to determine glyphosate, N-(phosphonomethyl)glycine, and its major metabolite, (aminomethyl)phosphonic acid in groundwater and soil. The methods involve ligand-exchange, anioon-exchange and derivatisation and final identification and quantification by GC-MS. The limits of quantification in this experiment were 0.1 mug -1 for both compounds in water and 0.006 mug g-1 for both compounds in soil. Decomposition in soil and occurrence in groundwater of the herbicide glyphosate was studied after its application for weed control on a Swedish railway embankment.

Bossard, C. C., J. M. Randall, et al., Eds. (2000). Invasive plants of California's wildlands. Berkeley, University of California Press

Busse, M. D., A. W. Ratcliff, et al. (2001). "Glyphosate toxicity and the effects of long-term vegetation control on soil microbial communities." Soil Biology & Biochemistry 33(12-13): 1777-1789

We assessed the direct and indirect effect of the herbicide glyphosate on soil microbial communities from ponderosa pine (Pinus ponderosa) plantations of varying site quality. Direct, toxic effects were tested using culture media and soil bioassays at glyphosate concentrations up to 100-fold greater than expected following a single field application. Indirect effects on microbial biomass, respiration, and metabolic diversity (Biolog and catabolic response profile) were compared seasonally after 9-13 years of vegetation control using repeated glyphosate applications in a replicated field study. Three pine plantations were selected to provide a range of soil characteristics associated with glyphosate binding (clay, Fe and Al oxide content) and site growing potential from the lowest to the highest in northern California. Glyphosate was toxic to bacteria and fungi from each plantation when grown in soil-free media. Culturable populations were reduced, as was the growth rate and metabolic diversity of surviving bacteria, by increasing concentrations of glyphosate. This toxicity was not expressed when glyphosate was added directly to soil, however. Microbial respiration was unchanged at expected field concentrations (5-50 mug g-1), regardless of soil, and was stimulated by concentrations up to 100-fold greater. Increased microbial activity resulted from utilization of glyphosate as an available carbon substrate. Estimated N and P inputs from glyphosate were inconsequential to microbial activity. Long-term, repeated applications of glyphosate had minimal affect on seasonal microbial characteristics despite substantial changes in vegetation composition and growth. Instead, variation in microbial characteristics was a function of time of year and site quality. Community size, activity, and metabolic diversity generally were greatest in the spring and increased as site quality improved, regardless of herbicide treatment. Our findings suggest that artificial media assays are of limited relevance in predicting glyphosate toxicity to soil organisms and that field rate applications of glyphosate should have little or no affect on soil microbial communities in ponderosa pine plantations.

California Department of Food and Agriculture. (2006). "California Weed Management Areas." Retrieved Nov. 2, 2006, from http://www.cdfa.ca.gov/phpps/ipc/weedmgtareas/wma_index_hp.htm.

Weed Management Areas (WMAs) are local organizations that bring together landowners and managers (private, city, county, State, and Federal) in a county, multi-county, or other geographical area to coordinate efforts and expertise against common invasive weed species. The WMA functions under the authority of a mutually developed memorandum of understanding (MOU) and is subject to statutory and regulatory weed control requirements. A WMA may be voluntarily governed by a chairperson or a steering committee. To date, groups in California have been initiated by either the leadership of the County Agricultural Commissioner’s Office or a Federal Agency employee. WMAs are unique because they attempt to address agricultural (regulatory) weeds and “wildland” weeds under one local umbrella of organization. It is hoped that participation will extend from all agencies and private organizations. WMAs have printed weed I.D./control brochures, organized weed education events, written and obtained grants, coordinated demonstration plots, and instituted joint eradication, mapping, outreach, and other effective weed management projects.

California Department of Food and Agriculture - Pesticide Investigations Unit (2000). Control of Giant Cane in Riparian and Wetland Areas of Northern and Central California, California Department of Food and Agriculture (http://teamarundo.org/control_manage/DFG-EPAreport.html).

This project has three primary objectives: (1) to determine the best methods for giant cane control in northern and central California; (2) to educate the public regarding the giant cane threat; and (3) to gather information regarding giant cane’s current presence in northern and central California and its potential for further invasive spread in the region. These objectives were accomplished via the following four tasks:

1) the establishment of a giant cane control demonstration project; 2) the completion of an herbicide risk assessment for nontarget aquatic species; 3) the development of giant cane educational materials; and 4) the completion of a giant cane survey project for northern and central California.

California Environmental Resources Information System. (2006). "California Environmental Resources Information System (CERES) site on invasive species." Retrieved Nov. 3, 2006, from http://www.ceres.ca.gov/theme/invasives.html.

California Exotic Pest Plant Council (1993). Arundo Donax Workshop Proceedings. Arundo Donax Workshop Proceedings, Ontario, CA, Riverside County Parks Department (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).

California Exotic Pest Plant Council (1998). Arundo and Salt Cedar: The Deadly Duo, A Workshop on Combating the Threat from Arundo and Salt Cedar. Arundo and Salt Cedar: The Deadly Duo, Ontario, CA, University of California Coorperative Extension, Imperial County (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).

California Interagency Noxious Weed Coordinating Committee. (2006, Nov. 2, 2006). "CALWEED DATABASE: California Noxious Weed Control Projects Inventory." from http://endeavor.des.ucdavis.edu/weeds/.

The California Interagency Noxious Weed Coordinating Committee is a group of sixteen State and Federal agencies meeting quarterly, in conjunction with stakeholders, to coordinate activities with respect to noxious weed control. A central project of the group has been to create an Internet accessible database, which acts as a clearing-house for noxious weed control projects in California. The database contains information on who is controlling which noxious weeds in California and what methods they are using. This information is searchable by keywords.

Projects which qualify for this database attempt to eradicate or reduce the number of noxious weeds in California. The emphasis of the database is on weeds considered noxious by the California Department of Food & Agriculture or a threat to wildlands by the California Exotic Plant Pest Council.

The projects in the Calweed Database have been incorportated into the Natural Resource Projects Inventory (NRPI).

Carlisle, S. M. and J. T. Trevors (1986). "Effect of the herbicide glyphosate on nitrification, denitrification and acetylene reduction in soil." Water Air and Soil Pollution 29(2): 189-204

The effect of glyphosate on N2 fixation, denitrification, and nitrification in an agricultural soil was investigated. Effects of the pure herbicide and commerical formulation, Roundup (Monsanto Company), were compared in soil under aerobic and anaerobic conditions. Anaerobic C2H2 reduction was inhibited by high herbicide levels. Denitrification in non-amended soil was either unaffected (N2O reduction) or stimulated (NO3- reduction); in glucose-amended soil, N2O reduction was inhibited and NO3-reduction unaffected by both glyphosphate and Roundup. Roundup caused greater stimulation of N2O reduction than pure glyphosate; no other significant formulation effects were observed. Nitrification was inhibited by the two formulations. Ammonium oxidation were both influenced. Pure glyphosate was more inhibitory than Roundup. No toxicity to any of these activities should be seen at recommended field application rates of the herbicide.

Carlisle, S. M. and J. T. Trevors (1986). "Effect of the herbicide glyphosate on respiration and hydrogen consumption in soil." Water Air and Soil Pollution 27(3-4): 391-402

The effect of glyphosate on soil respiration and H2 oxidation in an agricultural soil was investigated. The effects of the pure herbicide and commercial formulation, Roundup (Monsanto Company), were compared in soil under both aerobic and anaerobic conditions. Both formulations stimulated O2 uptake as well as aerobic and anaerobic CO2 evolution. Roundup caused more stimulation than glyphosate under aerobic incubation conditions; the formulations had an equal effect on anaerobic CO2 evolution. Hydrogen oxidation was inhibited by both formulations in aerobic and anaerobic soil. Aerobic H2 oxidation was inhibited to the same extent by both formulations; Roundup had a stronger inhibitory effect on anaerobic H2 oxidation than did glyphosphate.

Center for Invasive Plant Management. (2006). "Center for Invasive Plant Management." Retrieved Nov. 2, 2006, from http://www.weedcenter.org.

The Center for Invasive Plant Management (CIPM) supports natural resource managers, scientists, and educators pursuing ecological approaches to invasive plant management.

Chakravarty, P. and L. Chatarpaul (1990). "Non-target effect of herbicides: I. Effect of glyphosate and hexazinone on soil microbial activity: Microbial population, and in-vitro growth of ectomycorrhizal fungi." Pesticide Science 28(3): 233-242

The effects of two herbides, glyphosate (as a 359 g litre-1 SL) and hexazinone (as a 50 g kg-1 granules) on soil microbial population, carbon dioxide evolution, and in-vitro growth of five species of ectomycorrhizal fungi were investigated. Glyphosate at 0.54 and 3.23 kg a.i. ha-1 and hexazinone at 1, 2 and 8 kg a.i. ha-1 did not reduce soil microbial population or carbon dioxide evolution in the long term (6 months). However, there was a significant short-term (2 months) effects of glyphosate on both fungal and bacterial counts at the 0.54 kg ha-1 treatment. In in-vitro tests, Cenococcum graniforme, Hebeloma crustuliniforme and Laccaria laccata were more susceptible to both herbicides than was Suillus tomentosus, which was, in turn, more susceptible than Paxillus involutus. The growth of all five ectomycorrhizal fungi was significantly reduced when subjected to concentrations above 50 .mu.l formulation litre-1 (glyphosate) or 50 .mu.g formulation litre-1 (hexazinone).

Cornish, P. S. (1992). "Glyphosate residues in a sandy soil affect tomato transplants." Australian Journal of Experimental Agriculture 32(3): 395-399

Glyphosate residues in a loamy sand soil were suspected of damaging transplanted tomatoes at Gosford in 1990. Field and glasshouse experiments were conducted to determine whether phytotoxic residues of glyphosate persist in this soil type and, if so, under what conditions. In the glasshouse experiment, visible symptoms of glyphosate toxicity occurred in tomato seedlings transplanted into soil that was sprayed 1, 5 or 15 days earlier with glyphosate (360 g a.i./L) at 4 L product/ha. Glyphosate also reduced plant dry weight (16 days after transplanting), but only where soil nutrient deficiencies were corrected after transplanting. In this case, seedlings transplanted 15 days after spraying suffered an average reduction in dry weight of 57%. Greater reductions in dry weight occurred where superphosphate (43 kg P/ha) was mixed through soil before spraying (75 vs. 35% reduction). In the field, glyphosate residues reduced plant dry weight 16 days after transplanting, even when transplanting followed spraying by up to 9 days, and possibly as many as 30. At 9 days, reductions of 50, 74 and 78% were recorded with glyphosate (360 g a.i./L) applied at 2, 4 and 8 L/ha, respectively. Effects of glyphosate on fruit yield were significant (P < 0.05), but much smaller than effects on earlier plant dry weights. The phytotoxicity of glyphosate residues in this loamy sand appears to result from a combination of inherently low P sorption capacity and application of superphosphate, leading to low adsorption of glyphosate by soil. This may be exacerbated when dry conditions occur between application and planting. On the present evidence, a plant-back period of 3 weeks could be considered safe when transplanting tomatoes into this sandy soil, provided some mixing of soil occurs at transplanting. It is recommended that farmers perform a simple bioassay to confirm safety.

de Jonge, H. and L. W. de Jonge (1999). "Influence of pH and solution composition on the sorption of glyphosate and prochloraz to a sandy loam soil." Chemosphere 39(5): 753-763

Standard protocols for batch sorption experiments prescribe the use of 0.01 M CaCl2 as the aqueous solution, but sorption can strongly depend on the solution composition. The present work quantifies the variation in sorption behavior of the herbicide glyphosate and the fungicide prochloraz to a sandy loam soil, arising from differences in pH, ionic strength, ortho-phosphate concentration, and dominant cation in solution (Ca2+, K+, NH4+). Using batch experiments, we measured the amount sorbed to the bulk fraction and clay-sized particles. From the adsorption and desorption isotherms, we estimated the Freundlich parameters, Kf and N. Sorption isotherms were mostly non-linear and manifested adsorption-desorption non-singularity. Adsorption Kf values were in the range 0.6-78.5 L kg-1 for glyphosate and 31.2-155 for prochloraz. The pH and ortho-phosphate affected the sorption of both glyphosate and prochloraz, whereas ionic strength and dominant cation only affected sorption of glyphosate.

De Marco, A., C. De Simone, et al. (1992). "Importance of the type of soil for the induction of micronuclei and the growth of primary roots of Vicia faba treated with the herbicides atrazine, glyphosate and maleic hydrazide." Mutation Research 279(1): 9-13

Research was carried out on the genotoxic effects (induction of micronucleated cells in primary root tips) and toxic effects (reduction in primary root growth) in young plants of Vicia faba grown in soils with different organic matter contents and treated with the herbicides atrazine, glyphosate and maleic hydrazide. The data obtained show that the genotoxic effects are noticeably influenced by the interactions between the herbicide and the type of soil in which the Vicia faba have grown. While maleic hydrazide proved to be highly clastogenic for young plants grown in both soils, atrazine was genotoxic only in younger plants grown in soil poor in organic matter. Glyphosate did not induce micronuclei under either soil condition, but induced a significant toxic effect.

De Waal, L. C. (1994). Ecology and management of invasive riverside plants. Chichester ; New York, Published for the International Centre of Landscape Ecology by Wiley

Decruyenaere, J. G. and J. S. Holt (2001). "Seasonality of clonal propagation in giant reed." Weed Science 49(6): 760-767

Vegetative propagules of an invasive riparian weed, giant reed, were collected monthly from two Southern California sites and planted in a greenhouse from August 1998 to July 1999. Rooting and emergence frequency of planted pieces and time to emergence, growth rate, and number of developing shoots were recorded; soluble carbohydrates were analyzed. Response variables were regressed against climatic, seasonal, and site effects using a stepwise model. Rhizomes established much more frequently than stems in all months. Time of year of collection was found to be the most important factor determining establishment of all propagule types. The interaction of maximum daily temperature and precipitation at the field sites had a lesser, but significant effect on rooting frequency. The lack of a consistent correlation between any of the response variables and climate or site may indicate broad environmental tolerance. Seasonal patterns in emergence, growth, and soluble carbohydrates suggest that control by shoot removal would be most effective in fall when rhizome carbohydrate reserves are the lowest, resulting in the greatest reduction in regrowth. Chemical control with phloem-mobile herbicides would be most effective in late summer or early fall, when carbohydrates are moving from leaves to belowground structures but prior to natural leaf senescence.

Delfosse, E. S. (2000). "Biological Control: Important Tool for Managing Invasive Species." Agricultural Research 48(3): 2

Descalzo, R. C., Z. K. Punja, et al. (1995). "Effect of herbicide-treated bean plants on the population dynamics of glyphosate-synergistic Pythium in the soil." Canadian Journal of Plant Pathology 17(4): 367-368

Devlin, R. M., S. J. Karczmarczyk, et al. (1986). "Initial and Residual Activity of Glyphosate and Sc-0224 in A Sandy Soil." Crop Protection 5(4): 293-296

Dudley, T. (2003). "Arundo donax Detailed Report." from http://ucce.ucdavis.edu/datastore/detailreport.cfm?usernumber=8&surveynumber=182.

Dudley, T. a. B. C. (1995). Biological invasions in California wetlands: the impacts and control of non-indigenous species in natural areas. Oakland, Pacific Institute for SIDES

Duran, N. L., K. A. Urick, et al. (2001). "Effects of aldicarb and atrazine on the microbial community structure and denitrification potential in soils from a riparian buffer restoration site." Abstracts of the General Meeting of the American Society for Microbiology 101: 643

Riparian buffers are vegetative areas along aquatic habitats that help minimize the movement of soils and reduce the nutrient loadings (nitrogen and phosphorus) into rivers and streams. In order to use riparian buffers as management tools, it is necessary to evaluate their nitrate removal capacity and the effects that anthropogenic chemicals may have in this process. Therefore, this study was conducted to investigate the effects of aldicarb (a pesticide) and atrazine (a herbicide) on the microbial community structure and denitrification potential of a riparian buffer restoration site using molecular biology techniques. Oligonucleotide primers specific for the nirK and nirS nitrite reductase genes were used to detect the denitrifying bacteria present in microcosms amended with aldicarb or atrazine via touchdown PCR. Sample DNA from all treatments revealed amplification of the nirK and nirS genes. However, the atrazine-treatments demonstrated weak band patterns visible only after reamplification. In addition, phospholipid fatty acid (PLFA) analyses revealed a shift in the microbial community structure and early stages of membrane toxicity were also observed as a result of atrazine exposure. Further characterization of the riparian restoration site indicated that the streambed zone had the highest microbial biomass content, heightened levels of toxicity, increased levels of Gram-positive and Gram-negative/anaerobic bacteria, and lower levels of actinomycetes and sulfur reducers as compared to the pasture area and vegetative riparian zone. The results of this study indicate that the presence of anthropogenic chemicals can impact the microbial communities and reduce the nitrate attenuation effectiveness of riparian buffers.

Eberbach, P. L. and L. A. Douglas (1991). "Method for the determination of glyphosate and (aminomethyl)phosphonic acid in soil using electron capture gas chromatography." Journal of Agricultural and Food Chemistry 39(10): 1776-1780

A procedure for extraction of the phosphonic acid herbicide glyphosate and its metabolite (aminomethyl)phosphonic acid from soils and for analysis of these two compounds by electron capture gas chromatography is described. Both compounds were extracted from the soil with aqueous triethylamine, cleaned up with anion- and cation-exchange resins, and derivatized in a single-step procedure with trifluoroacetic anhydride and trifluoroethanol. Where extraction of soil immediately followed fortification, recovery of glyphosate ranged from 88% to 104%. However, where extraction was delayed 13 h after fortification, the recovery of glyphosate varied from 48% to 67%. This low recovery of glyphosate was thought to be due to adsorption of some of the herbicide to soil particles during the period prior to extraction. This suggested that triethylamine was able to extract soluble glyphosate and weakly adsorbed glyphosate but not glyphosate that was strongly adsorbed during a pre-extraction period.

Forlani, G., A. Mangiagalli, et al. (1999). "Degradation of the phosphonate herbicide glyphosate in soil: Evidence for a possible involvement of unculturable microorganisms." Soil Biology & Biochemistry 31(7): 991-997

The properties of microbial strains responsible for the rapid mineralization of the herbicide glyphosate in soil were investigated in soil-water mixtures supplemented with 10 mmol l-1 active ingredient. Over 2 weeks degradation kinetics were linear, as expected in the case of non-growth-linked metabolization, and the rate of utilization was not enhanced following repeated treatment of the soil with increasing herbicide doses. The availability of exceeding phosphorus, nitrogen and carbon sources did not affect the rate of glyphosate utilization, that was maximal under conditions of neutral pH, high oxygen and low osmolarity. The screening of 1200 bacterial strains isolated on a rich medium in the absence of the herbicide failed to identify any strain able to cleave the glyphosate molecule. When antibiotics with different mode of action were added to the mixtures. while some inhibitors of protein synthesis exerted considerable effects, those that are active only against actively-proliferating cells were scarcely effective. An MPN analysis was performed to enumerate degrading microorganisms, but in no dilution the same extent of utilization measured in the original mixture could be found. Results suggest that at least the first steps in herbicide degradation could be accomplished by some microbial species unable to grow in vitro and form visible colonies on plates.

Frandsen, P. (1994). "Team Arundo: an interagency success story." California Weed Conference. Proceedings 46: 157-161

Frandsen, P., Jackson, N. (1998). Santa Ana River Interagency Habitat Recovery Project, Van Buren Bridge Project Area Summary. Arundo and Salt Cedar: The Deadly Duo, A Workshop on Combating the Threat from Arundo and Salt Cedar. C. E. Bell. Ontario, CA, University of California Cooperative Extension, Imperial County: 47-48 (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).

Frandsen, P. R. (1997). Team Arundo: Interagency cooperation to control giant cane (Arundo donax). Assessment and Management of Plant Invasions. J. O. Luken, Thieret, J. W. New York, Springer: 244-248

Gaffney, K. A. "Post eradication restoration protocols." from http://www.crpinc.org/eco/restoration.html#restore.

Gaffney, K. A. (2000). Invasive plants in riparian corridors: Distribution, control methods, and plant community effects. Rohnert Park, CA, Sonoma State University

Gaffney, K. A. (2002). "Giant Reed in the Russian River Watershed: Distribution, Plant Community Effects & Control Methods." from http://teamarundo.org/papers/GaffneyPres071002_files/frame.htm.

Gard, J. K., P. C. C. Feng, et al. (1997). "Nuclear magnetic resonance timecourse studies of glyphosate metabolism by microbial soil isolates." Xenobiotica 27(7): 633-644

1. Triple Resonance Isotope EDited nmr spectroscopy (TRIED) has been developed to detect and examine minute levels of glyphosate metabolites in microbial soil isolates. Using stable isotopic labelling (13C and 15N), TRIED allows the simultaneous detection of multiple metabolites in crude matrices at submicrogram levels. An improvement over earlier techniques where milligrams are needed, TRIED can detect 500 ng of triply labelled compound in a crude sample (1:14000 mass ratio) in just hours. 2. TRIED is used here to compare the kinetics and metabolic pathways of glyphosate metabolism by two strains of Ochrobactrum anthropi, LBAA and S5. Both LBAA and S5 appear to metabolize glyphosate primarily via the aminomethylphosphonate (AMPA) pathway, since no detectable levels of glycine or sarcosine are observed in the media or lysates of either microbe. The formation of N-methylAMPA is common to the metabolism of both microorganisms, but N-acetylAMPA is observed only in LBAA. N-methylacetamide is detected predominantly in media and lysates of S5, although some evidence also points to the formation of this metabolite in LBAA. 3. Results are consistent with conventional radioactive tracer studies. TRIED nmr provides more specific structural information complementary to radiolabel methods. Both nmr and radioactivity studies show S5 glyphosate metabolism to be much slower than that of LBAA.

Giessow, J. a. J. G. (2001). Planning: Arundo donax removal: A review of methods for control and biomass removal. Proceedings, California Exotic Pest Plant Council Symposiums: Achievements and Challenges in Wildland Weed Management. M. Kelly. Berkeley, CA, California Exotic Pest Plant Council. 6: 85 (http://www.cal-ipc.org/symposia/archive/index.php#2002).

Gomez, M. A. and M. A. Sagardoy "The effect of glyphosate on aerobic bacteria that colonize a sandy soil." Anales de Edafologia y Agrobiologia 44(1-2): 119-130

From a sandy soil of the semiarid zone of the Province of Buenos Aires, Argentina, 519 bacterial strains were isolated and their genera were identified. Furthermore the effect of the herbicide on the principal microbial groups was also studied. The results indicate that within the Gram positive bacteria, coryneform bacteria and Bacillus spp. were predominant microorganisms. In the Gram negative bacteria the Acinetobacter was found to be the dominant genus. The herbicide, as different dosis, had little effect on the bacteria that colonize the soil. Neither any deleterious effect was detected on the potential of these bacterial strains as participants in the nitrogen cycle. The application of the herbicide to sterilized soil at the dosis of 40 l/h did not produce any deleterious effect on eurythermic bacteria of the types coryneform, Bacillus spp. or Acetobacter 307. However, after 10 days of incubation, the number of Acinetobacter 218 was found to decrease. The imperceptible effect produced by glyphosate on the bacteria which normally colonize such soil suggests that the use of the herbicide would not produce any significant alteration in that biological component of the ecosystem soil.

Gomez, M. A. and M. A. Sagardoy "Influence of glyphosate herbicide on the microflora and mesofauna of a sandy soil in a semiarid region." Revista Latinoamericana de Microbiologia 27(4): 351-358

The effect of four applications (0, 2, 4 and 8 l/ha) of the herbicide glyphosate (N-phosphonomethyl glycine) on the total numbers of aerobic bacteria, micro-arthropods, mites and springtails were studied periodically during 96 days in a sandy soil located in the semiarid region of the Buenos Aires Province, Argentine. The total numbers of the microflora did not change significantly (P = 0.05) neither with time nor with the mentioned treatments. The total numbers of the other groups were unaffected significantly by the herbicide treatments. However, significantly variations with time (p < 0.01) took place in the microarthropod population. Furthermore a highly significant (r = 0.95**) relation was obtained between the total numbers of arthropods and mites. Soil humidity was shown to have no effect on the total number of the organisms studied. From the results, it may be concluded that the glyphosate herbicide, applied even in amounts double that usually recommended do not produce harmful effects on the microflora and the mesofauna studied.

Griggs, T., D. Peterson, et al. (1997). "Riparian forest restoration along the Sacramento River, California." Bulletin of the Ecological Society of America 78(4 SUPPL): 99

Haney, R. L., S. A. Senseman, et al. (2000). "Effect of glyphosate on soil microbial activity and biomass." Weed Science 48(1): 89-93

Herbicides applied to soils potentially affect soil microbial activity. Quantity and frequency of glyphosate application have escalated with the advent of glyphosate-tolerant crops. The objective of this study was to determine the effect of increasing glyphosate application rate on soil microbial biomass and activity. The soil used was Weswood silt loam. The isopropylamine salt of glyphosate was added at rates of 47, 94, 140, and 234 mug ai g-1 soil based on an assumed 2-mm glyphosate-soil interaction depth. Glyphosate significantly stimulated soil microbial activity as measured by C and N mineralization but did not affect soil microbial biomass. Cumulative C mineralization, as well as mineralization rate, increased with increasing glyphosate rate. Strong linear relationships between mineralized C and N and the amount of C and N added as glyphosate (r2 = 0.995, 0.996) and slopes approximating one indicated that glyphosate was the direct cause of the enhanced microbial activity. An increase in C mineralization rate occurred the first day following glyphosate addition and continued for 14 d. Glyphosate appeared to be directly and rapidly degraded by microbes, even at high application rates, without adversely affecting microbial activity.

Haney, R. L., S. A. Senseman, et al. (2002). "Soil carbon and nitrogen mineralization as affected by atrazine and glyphosate." Biology and Fertility of Soils 35(1): 35-40

Atrazine alone and atrazine plus glyphosate were added to soil to determine their effect on soil microbial activity as measured by C and N mineralization (Cmin, Nmin) and soil extractable atrazine without the use of radiolabelled isotopes. Atrazine alone was added to soils as a formulated product (Aatrex 4L) at a field rate of 2X(94 mg kg-1), 4X(188 mg kg-1), and 6X(282 mg kg-1) with an assumed soil penetration depth of 58 mm. Glyphosate, as Roundup Ultra, was added along with atrazine to soil in equal amounts bringing the total cumulative herbicide amount to 2X(188 mg kg-1), 4X(376 mg kg-1) and 6X(564 mg kg-1) assuming a 2-mm soil penetration depth for glyphosate. Atrazine plus glyphosate stimulated microbial activity more than atrazine alone. During 56 days of incubation, mineralized C and N were highly correlated (r2=0.93). In addition, the C and N added from the herbicides were correlated with the amounts of C and N mineralized above the controls and were highly correlated (r2=0.93 for Cmin and r2=0.97 for Nmin). Cmin was greatest during the first 7 days of incubation after herbicide application while Nmin was greatest during the day 14 to day 28 period indicating a possible substrate shift from glyphosate to atrazine since atrazine has more N relative to C than glyphosate. Atrazine extracted from soil at four time periods (day 7, 14, 28, and 56) showed similar degradation curves (DT50=10.5 days) for the atrazine and atrazine-glyphosate treatments for all rates, with the exception of the 6X rate after 14 days and the 2X rate after 28 days of incubation where glyphosate appeared to slightly enhance the degradation of atrazine.

Holman, D. (2002). "Combined efforts rid area of invasive reeds." American City & County 117(3): 16

Jackson, N. E., Frandsen, P., Douthit, S. (1993). "How to remove Arundo donax" The menu. Arundo donax workshop proceedings, Nov. 19, 1993. N. E. Jackson, Frandsen, P., Douthit, S. Ontario, CA, Riverside County Parks Department: 75-81 (http://teamarundo.org/ecology_impacts/proc93/proc93_index.html).

Jackson, N. E. (1998). Chemical Control of Giant Reed (Arundo donax) and Saltcedar (Tamarix ramosissima). Arundo and Salt Cedar: The Deadly Duo, A Workshop on Combating the Threat from Arundo and Salt Cedar. C. E. Bell. Ontario, CA, University of California Cooperative Extension, Imperial County: 33-42 (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).

Kaiser, J. (1999). "Stemming the Tide of Invading Species." Science 285(5435): 1836

The increase of international trade and travel have brought about an corresponding increase in invasive species in virtually every country, and more dramatic steps are being taken to eradicate them. Prevention remains the most effective approach, and many are calling for more stringent import regulations, especially in connection with the pet and plant industries.

Kirk, A. (2003). The Potential contribution of Natural Enemies from Mediterranean Europe to the Management of the Invasive Weed Arundo donax (Graminae; Arundinae) in the US. Proceedings of the California Invasive Plant Council Symposium: Planning Weed Management for Ecosystem Recovery. C. Pirosko. Berkeley, California, California Invasive Plant Council. 7: 62-28 (http://www.cal-ipc.org/symposia/archive/index.php#2002).

The potential contribution of natural enemies from Mediterranean Europe to the management of the invasive weed Arundo donax (Graminae; Arundinae) in the US

Kirk, A.A.1, T. Widmer1, G. Campobasso1, R. Carruthers2, and T. Dudley2 1USDA-ARS, European Biological Control Laboratory 2USDA-ARS, Western Regional Research Center, Exotic and Invasive Weed Research Unit <ric@pw.usda.gov>

Arundo donax, Giant reed, is a widespread invasive weed in California and the southwestern US. It ranges from the Canary Islands to northern Myanmar. It is a biocontrol target because of its intransigence to cultural and chemical control and its disastrous impact on the local ecology. Foreign exploration in Nepal and India revealed little sign of natural control whereas collections made around the Mediterranean resulted in 3 Hymenoptera, 5 Diptera, and a scale species plus several plant diseases, which cause death of shoots, tips and dormant buds. On average 55% of an Arundo stand is dead in the region around Montpellier France. Preliminary results suggest mortality may be attributed to Diptera (24%), and scale insects (14%), with Hymenoptera and fungal pathogens also playing a role. Infested areas of California and parts of the Mediterranean basin are excellent climatic matches. These results suggest that the Mediterranean is likely to be a profitable area to explore for natural enemies. Characterization of Arundo samples from Europe, Africa, Asia, North America and Australia may elucidate its center of origin.

Korol, R. V. (1985). "Regulation of Glyphosate Content in the Soil." Gigiena i Sanitariya(8): 71-72

Krzysko-Lupicka, T. and A. Orlik (1997). "The use of glyphosate as the sole source of phosphorus or carbon for the selection of soil-borne fungal strains capable to degrade this herbicide." Chemosphere 34(12): 2601-2605

The herbicide glyphosate was used as a selection agent for isolation of fungal strains capable to degrade phosphorus-to-carbon bond from standard sandy-clay soil. The studies have shown that the herbicide used in Martin medium as a sole source of phosphorus or carbon caused the decrease of the fungal population and substantially changed strain composition, thus selecting those which are able to degrade glyphosate.

Lawson, D. a. H. S. (2001). Evaluation of chipped Arundo biomass as mulch. Proceedings, California Exotic Pest Plant Council Symposiums: Achievements and Challenges in Wildland Weed Management. M. Kelly. Berkeley, CA, California Exotic Pest Plant. 6: 64-76 (http://www.cal-ipc.org/symposia/archive/index.php#2002).

Lawson, D. M., J. A. Giessow, et al. (2001). The Santa Margarita River Arundo donax Control Project: Development of Methods and Plant Community Response. USGS/USFWS Conference, Pomona, CA, In press. USGS/USFWS Conference, Planning for Biodiversity: Bringing Research and Management Together

A large-scale effort to control the aggressively invasive exotic species Arundo donax in the Santa Margarita River watershed was initiated in 1997. The project was prompted by the need for Marine Corps Base, Camp Pendleton to address impacts to habitat for federally listed endangered species and wetlands regulated by the Army Corps of Engineers. As of 2000, 27 km of the main stem of the Santa Margarita River had been treated. The methods employed were tested in preliminary trials before widespread implementation, and additional techniques emerged during the course of the project. Although the primary target is A.donax, 14 other invasive exotic species that also threaten riparian ecosystem functions were treated when encountered. Vegetation monitoring transects were established in A.donax removal areas to document the effectiveness of the different treatments and recovery of the plant communities. A.donax was reduced by over 90 percent after the first treatment and accounted for less than 2 percent absolute cover after three follow-up treatments. An experiment testing low cost methods for establishing woody species after A.donax control was conducted. Cuttings were installed with no follow-up maintenance. Approximately 30 percent of Baccharis salicifolia, and large (3-6 m) willow cuttings survived 2 years.

Lemke, J. (2002). "Environmental Excavation Saves Nature Area of Giant Reed." from http://www.forester.net/gx_0201_environmental.html.

Levesque, C. A., J. E. Rahe, et al. (1987). "Effects of glyphosate on Fusarium spp.: Its influence on root colonization of weeds, propagule density in the soil, and crop emergence." Canadian Journal of Microbiology 33(5): 354-360

Glyphosate is a broad spectrum herbicide that can lead to root rot like damage on crops. This study was undertaken to investigate the effect of glyphosate on the root-colonizing Fusarium spp. The research was conducted at two sites. Site one was densely covered with perennial weeds, and site two with annuals. At site one, spraying the weed cover with glyphosate increased (p < 0.05) the level of colonization by Fusarium spp. in Ranunculus repens and Holcus lanatus, but not in Stellaria media and Plantago lanceolata. At site two, glyphosate enhanced colonization in Spergula arvensis, Stellaria media, Echinochloa crus-galli, and Chenopodium album, but not in Capsella bursa-pastoris and Polygonum persicaria. At both sites, the number of colony-forming units of Fusarium spp. per gram of dried soil was increased by the application of glyphosate. Nevertheless, crops subsequently sown in the field containing the annual weeds were not detrimentally affected by glyphosate treatment of these weeds.

Levesque, C. A., J. E. Rahe, et al. (1992). "The Effect of Soil Heat Treatment and Microflora on the Efficacy of Glyphosate in Seedlings." Weed Research 32(5): 363-373

Seedlings of wheat (Triticum aestivum L.) and beans (Phaseolus vulgaris L.) were less sensitive to glyphosate when grown in heat-treated soil than in raw soil. Pythium spp. and Fusarium spp. were not detected in heat-treated loam or muck soils at the time of glyphosate treatment, although fungi of several other genera were present. The efficacy of glyphosate on wheat or beans grown in heat-treated loam soil was restored when untreated aqueous soil extracts were added to the heat-treated soil. Bean seedlings grown in five different soil types varied in their sensitivity to glyphosate. The variation in LD50 among autoclaved soils was lower than that among raw soils. Between 13- to 47-fold more glyphosate was required to kill the bean seedlings in any of the autoclaved soils compared with their corresponding raw soils. This differential effect was not observed on bean seedlings sprayed with either 2,4-D or paraquat. LD50 values for glyphosate on apple (Malus domestica Borkh.) seedlings growing in previously sterilized loam soil were reduced by inoculation of the soil with a representative Fusarium sp. or Pythium sp. obtained earlier from apple seedlings treated with glyphosate, but not by a Cylindrocarpon sp. from apple or Pythium ultimum Trow from glyphosate-treated bean. The efficacy of glyphosate on bean, wheat or apple seedlings can be affected by changes in certain microbial components of the soil.

Lowrey, J. and J. Watson (2004). Tamarisk and Arundo control on Cache Creek. Annual Meeting on Weed Management: Economic and Environmental Savings. Sacramento, California. 56: 82-83

Luken, J. O. and J. W. Thieret (1997). Assessment and management of plant invasions. New York, Springer

McLean, P. A., C. M. Liu, et al. (1989). "Toward Herbicide Resistant Plants Cloning of the Genes for Glyphosate Degradation from A Soil Organism and Their Expression in Escherichia-Coli." Journal of Cellular Biochemistry Supplement(13 PART D): 338

Miles, C. J. and H. A. Moye (1986). "Sorption of Glyphosate Herbicide on Soil and Clay." Abstracts of Papers American Chemical Society 191(9): NO PAGINATION

Miles, C. J. and H. A. Moye (1988). "Extraction of glyphosate herbicide from soil and clay minerals and determination of residues in soils." Journal of Agricultural and Food Chemistry 36(3): 486-491

Extraction of the herbicide glyphosate [N-(phosphonomethyl)glycine] from clay minerals and two soils was studied by a batch equilibrium technique. Experiments showed that, for most of the sorbent/solvent systems studied, the amount of herbicide extracted increased as pH increased, suggesitng that sorption occurs through ion exchange and hydrogen bonding. Alkaline solutions of kaolinite, iron oxide, and two Calvin silt leam soil samples showed resorption of glyphosate after an initial desorption step. Determination of glyphosate residues in soils was performed by derivatization of soil extracts with 9-fluorenylmethyl chloroformate and analysis by HPLC with fluorometric detection. Glyphosate was successfully recovered from sandy soils at 0.5 ppm by triplicate extraction with 0.1 M KH2PO4 and 30-fold concentration. For soils with high clay content, acceptable recovery at 1.0 ppm was achieved with triplicate extraction using 0.2 M KOH.

Mitchell, J. J., Giessow, and J. Giessow (2001). Role of the Santa Margarita and San Luis Rey Watersheds Weed Management Area in watershed-based exotic plant control and restoration in northern San Diego County. Proceedings, California Exotic Pest Plant Council Symposiums: Achievements and Challenges in Wildland Weed Management. M. Kelly. Berkeley, CA, California Exotic Pest Plant Council 6: 86 (http://www.cal-ipc.org/symposia/archive/index.php#2002).

Monheit, S. (2002). "Glyphosate-based aquatic herbicides: an overview of risk." Noxious Times 4(4): 5-9 (http://www.cdfa.ca.gov/phpps/ipc/noxioustimes/noxtimes_archives.htm).

Newhouser, M., C. Cornwall, et al. (1999). Arundo: A Landowner Handbook. Sonoma CA, Sonoma Ecology Center and California State University, Sacramento, Media Services (http://teamarundo.org/education/index.html#handbook).

This reference guide is intended to educate landowners about the invasive weed Arundo donax, the reasons for eliminating it from watersheds, and techniques for its eradication. We recommend conducting your initial outreach with letters and brochures, and then targeting the handbooks to specific landowners.

Newhouser, M., C. Cornwall, et al. (1999). Controlling Arundo in Your Watershed: A Guide for Organizations. Sonoma CA, Sonoma Ecology Center and California State University, Sacramento, Media Services (http://teamarundo.org/education/org_guide.pdf).

This is a primer for organizations that wish to start an Arundo eradication program in their watershed. These include nonprofits, government agencies, and Resource Conservation Districts, as well as restoration companies working with such organizations. Groups working to control and eliminate other non-native invasive species from riparian areas can also use this guide. Contents: Working with landowners, addressing landowner concerns, negotiating an eradication agreement, working with volunteers and other stakeholders, eradication techniques, prevention and public outreach, Arundo identification, additional resources, landowner agreement. Also includes a sample landowner-contractor agreement.

North American Weed Management Association. (2006). "North American Weed Management Association." Retrieved Nov. 2, 2006, 2006, from http://www.nawma.org/.

The mission of NAWMA is to provide education, regulatory direction, professional improvement, and environmental awareness to preserve and protect our natural resources from the degrading impacts of exotic, invasive noxious weeds.

Ogner, G. (1987). "Glyphosate Application in Forest Ecological Aspects II. the Quality of Water Leached from Forest Soil Lysimeters." Scandinavian Journal of Forest Research 2(4): 469-480

Olson, B. M. and C. W. Lindwall (1991). "Soil microbial activity under chemical fallow conditions: Effects of 2,4-D and glyphosate." Soil Biology and Biochemistry 23(11): 1071-1076

Field and laboratory studies were made to examine the effects of 2,4-D and glyphosate on soil microbial activity under zero-tillage chemical fallow conditions. Glyphosate and 2,4-D applied three consecutive times at field rates and 10 times the field rates had no effect on microbial biomass-C, C mineralization or nitrification in the field. Laboratory studies showed that 2 and 100 times the field rate of 2,4-D reduced nitrification by 11 and 79%, respectively. In laboratory studies, 2,4-D incorporated into the soil reduced nitrification, but surface-applied 2,4-D did not. Glyphosate and 2,4-D used as recommended should not affect microbial activity under dryland zero-tillage chemical fallow conditions.

Omori, G. (1996). Eradicating the giant reed (Arundo donax) in riparian areas of Marine Corps Base, Camp Pendleton, California. Oceanside, CA, Agri Chemical & Supply, Inc.: 20

Pimentel, D. (2000). "Biological Control of Invading Species." Science 289(5481): 869

Ragab, M. T. H., M. K. H. Abdel-Kader, et al. "Fate of glyphosate in a sandy loam soil and analysis for residues in field-grown crops." Proceedings of the Nova Scotian Institute of Science 35(2): 67-70

Following application in the spring to a sandy loam soil, residues of glyphosate (N-phosphonomethyl glycine) decreased rapidly and degraded into aminomethylphosphonic acid which also was short lived. Analysis for glyphosate and its metabolite as their methyl trifluoroacetate derivatives was by the flame specific phosphorus gas chromatography. Glyphosate and its metabolite in the soil at 1, 10, 19, 29, 52, 86 and 122 days after application was 69.5, 29.6, 22.1, 14.1, 11.7, 4.2 and 0.0% and 2.3, 31.0, 35.2, 24.0, 15.0, 9.4 and 6.1%, respectively, of the 4.25 kg a.i./ha applied. Neither compound was found in field-growth barley, oat, wheat corn, beans, peas, red beet or carrots. No injury symptoms were observed on any of the crops during the growing season.

Rahe, J. E., G. S. Johal, et al. (1989). "Synergistic Role of Soil Fungi in the Herbicidal Activity of Glyphosate." Abstracts of Papers American Chemical Society 197: AGRO 138

Sanderson, J. B., J. A. MacLeod, et al. (1999). "Glyphosate application and timing of tillage of red clover affects potato response to N, soil N profile, and root and soil nematodes." Canadian Journal of Soil Science 79(1): 65-72

The effects of glyphosate application and time of tillage of red clover on soil NO3-N profiles, the response of the subsequent potato crop to varying rates of N fertilizer application, and root and soil nematodes, were evaluated. The study was conducted over three cropping seasons on a Charlottetown fine sandy loam on Prince Edward Island. Red clover was moldboard ploughed in mid-September (early fall), or moldboard or chisel ploughed in mid-October (late fall), or moldboard ploughed in the spring. Glyphosate was applied in early fall and the dead clover was moldboard or chisel ploughed in mid-October or left undisturbed until spring. A barley control, where barley was harvested and straw incorporated with a tandem disc harrow in early September, was included. Potato were planted with 6 rates of N (0 to 250 kg ha-1 in 50-kg increments) band applied at planting. The barley control treatment produced lower potato yield without fertilizer N in all 3 yr of the study compared to red clover treatments, but potato yields were similar at high rates of applied N. Potato tuber yields after spring moldboard ploughing of red clover were higher at low N rates and lower at high N rates than yields after late fall treatment in one year of the study. Concentrations of nitrate-N in the soil in mid-November were highest following the early fall moldboard ploughing and lowest in the undisturbed clover plots. Fall soil nitrate-N levels were intermediate following the glyphosate application and late fall tillages. Early spring soil nitrate-N levels in the surface 30 cm were generally highest with the spring and late fall tillage and lowest with the early fall tillage. Levels of nitrate-N in potato petioles increased with increased rates of N application and generally increased as tillage of the red clover was delayed from early fall to late fall to spring. In general, cultivation and the application of glyphosate did not affect soil and root nematode populations. In two instances, the moldboard plough tillage treatments were associated with higher levels of the clover-cyst nematode, Heterodera trifolii. One of the tillage treatments was combined with glyphosate, but this was the only case where the herbicide had an impact on nematodes. To maximize the benefits to the subsequent potato crop and to minimize leaching of nitrate, incorporation of legume residue should be delayed until the rate of mineralization and nitrification of the legume N is minimized. It is suggested that incorporation of red clover be delayed until after mid-October for clover-potato systems on PEI.

Santa Margarita and San Luis Rey Watersheds Weed Management Area. (2006). "Biology of Arundo donax." Retrieved Nov. 3, 2006, from http://smslrwma.org/invasives/Arundo/biology.html.

Santa Margarita and San Luis Rey Watersheds Weed Management Area. (2006). "Invasive Non-Native Plants - Plant Information, Distribution Maps, Mapping Methodology, Control Projects, and Control Methods." Retrieved Nov. 2, 2006, from http://smslrwma.org/invasives/index.html.

Santa Margarita and San Luis Rey Watersheds Weed Management Area. (2006). "Summary of Arundo Control Methods." Retrieved Nov. 2, 2006, from http://smslrwma.org/invasives/Arundo/controlmethods.html.

Schmitz, D. C. and D. Simberloff (2001). "Needed: A National Center for Biological Invasions." Issues in Science and Technology 17(4): 57

Schoenig, S. E., Ed. (2005). California noxious & invasive weed action plan. Sacramento, Calif., California Dept. of Food and Agriculture (http://www.cdfa.ca.gov/phpps/ipc/noxweedinfo/pdfs/noxious%5Fweed%5Fplan.pdf ).

Soulas, G. (1992). Biological Availability of Pesticides in Soil 2 4-D and Glyphosate as Test Cases. Proceedings of the International Symposium on Environmental Aspects of Pesticide Microbiology; Symposium, Sigtuna, Sweden, August 17-21, 1992. J. P. E. Anderson and E. AL. Upsala, Sweden, Swedish University of Agricultural Sciences: 219-224

Stein, E. D. (1998). Invasive Weed Control as Mitigaton: A Shifting Paradigm. Arundo and Salt Cedar: The Deadly Duo, A Workshop on Combating the Threat from Arundo and Salt Cedar. C. E. Bell. Ontario, CA, University of California Cooperative Extension, Imperial County: 27-32 (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).

Stelljes, K. B. (2001). "Research Off the Beaten Path." Agricultural Research 49(4): 14-17 (http://www.ars.usda.gov/is/AR/archive/apr01/path0401.htm).

Article and photos describing researchers' (UC Berkeley ecologist Thomas L. Dudley, ARS entomologists Raymond I. Carruthers and Alan A. Kirk, and ARS plant pathologist Timothy L. Widmer) search in Nepal for biological control agents for Arundo donax, tamarisk, and salt cedar.

Stratton, G. W. and K. E. Stewart (1991). "Effects of the herbicide glyphosate on nitrogen cycling in an acid forest soil." Water Air and Soil Pollution 60(3-4): 231-248

The herbicide glyphosate was sprayed aerially on a section of conifer forest in Atlantic Canada that had been previously clearcut and reforested. Glyphosphate was then tested for effects on ammonification, nitrification, and denitrification for a period of 8 months by comparing microbial activity in treated and untreated zones of the clay loam forest soil and the overlying decomposing litter, both with a pH of 3.8. With ammonification, there was generally a stimulation of activity in both the forest litter (FL) and forest soil (FS) that had been exposed to glyphosate during spraying. Nitrification rates in FL and FS were very low and glyphosate had no appreciable stimulatory or inhibitory effect on nitrification. Although glyphosate stimulated denitrification in a few instances, it generally had no significant effect no denitrification activity in FL and FS exposed during spraying. With all processes, microbial activity in FL was significantly greater than that in FS. Laboratory bioassays were also performed with FL and FS, as well as two silt loam (pH 5.8 and 6.4) and one sandy loam (pH 6.8) agricultural soils, using glyphosate concnetrations up to 200 times higher than field application rates. With ammonification and denitrification, glyphosate generally stimulated activity at all levels tested and in all soil used. Glyphosate stimulated ammonification by 50% at concentrations ranging from 140 to 550 .mu.g g-1 for the soils and > 4000 .mu.g g-1 for FL. With denitrification, the corresponding herbicide levels were approximately 2250 .mu.g g-1 for FS, > 10,000 for FL, and 450 for an agricultural soil. With nitrification, it was estimated that glyphosphate concentrations greater than 1000 to 2000 .mu.g g-1 would be required to cause a 50% inhibition of activity. The careful use of glyphosate in forestry should have no toxic effects on N cycling in soils.

Stratton, G. W. and K. E. Stewart (1992). "Glyphosate effects on microbial biomass in a coniferous forest soil." Environmental Toxicology and Water Quality 7(3): 223-236

The herbicide glyphosate (Roundup) was applied aerially to a conifer forest that had previously been clear-cut and reforested. Glyphosate was tested for effects on microbial biomass, numbers of selected microorganisms, and soil respiration over a period of 8 months by comparing treated and untreated zones of the clay loam forest soil (FS) and the overlying litter (FL), both pH 3.8. With microbial biomass, glyphosate generally had a stimulatory effect in FL, but usually no significant effect in FS. Glyphosate had no significant effect on numbers of bacteria, fungi, and actinomycetes in either FL or FS. The herbicide generally stimulated respiration in both FL and FS. In laboratory bioassays using FL, FS, and three agricultural soils, glyphosate had no significant effect on respiration when used at concentrations up to 100 times higher than recommended field application rates. Respiration rates in FL, as measured with Warburg respirometry, were unaffected by glyphosate. Respiration rates in FS were stimulated by glyphosate concentrations 10 and 100 times higher than recommended field rates. Glyphosate should have no deleterious effects on microbial biomass and respiration in forest soils when used under recommended conditions.

Sweeney, B. W., S. J. Czapka, et al. (2002). "Riparian forest restoration: Increasing success by reducing plant competition and herbivory." Restoration Ecology 10(2): 392-400

The reestablishment of riparian forest is often viewed as "best management practice" for restoring stream ecosystems to a quasi-natural state and preventing non-point source contaminants from entering them. We experimentally assessed seedling survivorship and growth of Quercus palustris (pin oak), Q. rubra (red oak), Q. alba (white oak), Betula nigra (river birch), and Acer rubrum (red maple) in response to root-stock type (bare root vs. containerized), herbivore protection (tree shelters), and weed control (herbicide, mowing, tree mats) over a 4-year period at two riparian sites near the Chester River in Maryland, U.S.A. We started with tree-stocking densities of 988/ha (400/ac) in the experimental plots and considered 50% survivorship (i.e., a density of 494/ha (200/ac) at crown closure) to be an "acceptable or minimum" target for riparian restoration. Results after four growing seasons show no significant difference in survivorship and growth between bare-root and containerized seedlings when averaged across all species and treatments. Overall survivorship and growth was significantly higher for sheltered versus unsheltered seedlings (49% and 77.6 cm vs. 12.1% and 3.6 cm, respectively) when averaged across all species and weed control treatments. Each of the five test species exhibited significantly higher 4-year growth with shelter protection when averaged across all other treatments, and all species but river birch had significantly higher survivorship in shelters during the period. Seedlings protected from weeds by herbicide exhibited significantly higher survivorship and growth than seedlings in all other weed-control treatments when averaged across all species and shelter treatments. The highest 4-year levels of survivorship/growth, when averaged across all species, was associated with seedlings protected by shelters and herbicide (88.8%/125.7 cm) and by shelters and weed mats (57.5%/73.5 cm). Thus, only plots where seedlings were assisted by a combination of tree shelters and either herbicide or tree mats exhibited an "acceptable or minimum" rate of survivorship (i.e., >50%) for riparian forest restoration in the region. Moreover, the combined growth and survivorship data suggest that crown closure over most small streams in need of restoration in the region can be achieved most rapidly (i.e., 15 years or less) by protecting seedlings with tree shelters and controlling competing vegetation with herbicides.

Tanjung, H. R. and J. E. Rahe (2000). "Soil fungi and herbicidal activity of glyphosate on seedlings of selected conifer and broadleaf species." Canadian Journal of Plant Pathology 22(2): 192-193

Thompson, D. G., D. G. Pitt, et al. (2000). "Comparative fate of glyphosate and triclopyr herbicides in the forest floor and mineral soil of an Acadian forest regeneration site." Canadian Journal of Forest Research 30(11): 1808-1816

Following applications of three different salt formulations of glyphosate (Vision(R), Touchdown(R), and Mon14420) and an ester formulation of triclopyr (Release(R)) to an Acadian forest regeneration site in New Brunswick, Canada, the fate and persistence of herbicide residues in the forest floor and underlying mineral soil were investigated. Within 14 days of treatment, maximal residue levels (average 8.3 mugcenter dotg dry mass-1) were observed in the forest floor matrix following application of the glyphosate formulations, with higher values (45.7 mugcenter dotg dry mass-1) observed for triclopyr. Residue maxima in the underlying mineral soil were, on average, 5.7-fold lower than those in the forest floor. In both matrices, glyphosate residues declined exponentially with time, irrespective of the formulation applied. Among the glyphosate treatments no significant differences (p = 0.16, p = 0.97, for forest floor and mineral soil, respectively) were observed in the estimated times to 50% dissipation (DT50). Overall, average DT50 values for glyphosate were estimated as 12 plus-minus 2 and 10 plus-minus 3 days for the forest floor matrix and mineral soil, respectively. Triclopyr residues, particularly in the forest floor, were characterized by a series of transient increases, possibly reflecting temporally varying inputs from dew, rainwash, or litter fall from surrounding treated vegetation. Triclopyr residues also dissipated with time, with approximate DT50 values ranging from 39 to 69 days in the forest floor and mineral soil, respectively.

Tracy, J. L., C. Jack DeLoach (1998). Suitability of Classical Biological Control for Giant Reed (Arundo donax). Arundo and Salt Cedar: The Deadly Duo, A Workshop on Combating the Threat from Arundo and Salt Cedar. C. E. Bell. Ontario, CA, University of California Cooperative Extension, Imperial County: 73-110 (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).

Trumbo, J. (1998). Comparison of three methods of glyphosate application and their effects in the control of Arundo donax. Sacramento, California Department of Fish and Game

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U.S. Department of Agriculture Agricultural Research Service. (2001). "More Troublesome Water Weeds Targeted by Researchers." Retrieved Nov. 3, 2006, from http://www.ars.usda.gov/is/AR/archive/nov01/water1101.htm.

Vartanian, V. (1998). Destructive Nature of Arundo and Tamarisk. Arundo and Salt Cedar: The Deadly Duo, A Workshop on Combating the Threat from Arundo and Salt Cedar. C. E. Bell. Ontario, CA, University of California Cooperative Extension, Imperial County: 7-13 (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).

Veiga, F., J. M. Zapata, et al. (2001). "Dynamics of glyphosate and aminomethylphosphonic acid in a forest soil in Galicia, north-west Spain." Science of the Total Environment 271(1-3): 135-144

Residues of the herbicide glyphosate (N-phosphonomethylglicine) and its main metabolite, aminomethylphosphonic acid (AMPA), were determined in a forest soil in north-west Spain, previously treated with 5 and 8 l ha-1 of glyphosate. Both products were monitored in the solid and liquid soil phases for an 8-week period after the treatment. Soil samples were extracted by KH2PO4. Concentrated extracts and liquid phase samples were derivatized with 9-fluorenylmethyl chloroformate (FMOC) before determination by HPLC using an anion exchange column and spectrofluorometric detection. The treated soil peaked at 6.9 mug g-1 of glyphosate, whereas soil water samples peaked at 0.74 mug ml-1 of glyphosate. One month after the treatment, both glyphosate and AMPA concentrations in soil and water samples were almost negligible. AMPA peaked at 0.77 mug ml-1 in soil water samples. Glyphosate and AMPA exhibited high vertical mobility in the treated soil, quickly reaching high concentrations in subsurface horizons where the degradation is slower.

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Waldecker, M. A. and D. L. Wyse (1985). "Soil moisture effects on glyphosate absorption and translocation in common milkweed (Asclepias syriaca)." Weed Science 33: 299-305

Absorption and translocation of 14C-glyphosate [N-(phosphonomethyl)glycine] by moisture-stressed common milkweed (Asclepias syriaca L.) was studied in greenhouse and growth chamber experiments. Water-stressed [13% (wt/wt) soil moisture] common milkweed plants treated with glyphosate at 1.1 kg ae/ha produced shoot regrowth equal to untreated plants, whereas shoot regrowth of nonstressed [25% (wt/wt) soil moisture] glyphosate-treated plants was only 6% of untreated plants. All shoot regrowth originated from buds on the proximal half of roots. Common milkweed plants, maintained at 25% soil moisture, absorbed 44% of the 14C-glyphosate applied and translocated 20% from the treated leaf, whereas plants at 13% soil moisture absorbed 29% and translocated 7%. Wiping the leaf with tissue paper wetted with distilled water or chloroform prior to 14C-glyphosate application increased absorption from 35 (unwiped leaves) to 62 and 77%, respectively, for plants at 25% soil moisture, and increased absorption from 14 to 42 and 46%, respectively, for plants at 13% soil moisture. Wiping failed to increase translocation out of the treated leaf for plants at either soil moisture regime. Latex samples taken from the abaxial leaf surface opposite 14C-glyphosate-treated leaves and from petioles of treated leaves did not contain 14C, indicating that glyphosate did not enter laticifers. Proximal root buds accumulated less 14C-radioactivity than distal root buds and had lower respiratory rates, suggesting that proximal root buds are more dormant than distal root buds and thus accumulate less glyphosate.

Wang, A. (1998). Groundwater nitrate levels as promoters of Arundo donax invasion. Environmental science : policy and practice. T. Dudley and K. Kennedy. Berkeley, CA Senior Research Seminar, Environmental Sciences Group Major, University of California: 507-515

Wardle, D. A. and D. Parkinson (1990). "Influence of the herbicide glyphosate on soil microbial community structure." Plant and Soil 122(1): 29-38

The side effects of glyphosate on the soil microflora were monitored by applying a range of glyphosate concentrations (0, 2, 20, and 200 .mu.g g-1 herbicide) to incubated soil samples, and following changes in various microbial groups over 27 days. Bacterial propagule numbers were temporarily enhanced by 20 .mu.g g-1 and 200 .mu.g g-1 glyphosate, while actinomycete and fungal propagule numbers were unaffected by glyphosate. The frequency of three fungal species on organic particles in soil was temporarily enhanced by 200 .mu.g g-1 glyphosate, while one was inhibited. One species was temporily enhanced on mineral particles. However, many of these fungi were inhibited by 200 .mu.g g-1 glyphosate in pure culture. There was little agreement between species responses to glyphosate in incubated soil samples and in pure culture.

Wardle, D. A. and D. Parkinson (1991). "Relative importance of the effect of 2,4-D, glyphosate, and environmental variables on the soil microbial biomass." Plant and Soil 134(2): 209-220

Two post-emergence herbicides (glyphosate and 2,4-D) were applied at field application levels to tilled field plots in a mixed cropping area in south-central Alberta. The effects of these chemicals on certain variables associated with microbial biomass and activity were monitored in these plots (as well as corresponding control plots) for 45 days. Glyphosate did not influence any of the microbial variables tested. Addition of 2,4-D significantly influenced all microbial variables investigated but these effects were transient, being detectable only within the first 1-5 days of herbicide addition. The effects of 2,4-D addition on the microbial variables tested, even when significant, were typically small and probably of little ecological consequence especially when spatial and temporal variation in these variables is taken into account.

Wardle, D. A. and D. Parkinson (1992). "The influence of the herbicide glyphosate on interspecific interactions between four soil fungal species." Mycological Research 96(3): 180-186

The influence of the herbicide glyphosate on two-way interactions between four fungal species [Mucor hiemalis, Mortierella alpina, Trichoderma harzianum, Arthrinium sphaerospermum] was investigated on agar using direct opposition, volatile inhibitor and non-volatile inhibitor tests, and on barley straw using tests for competitive saprotrophic ability. The results indicted that glyphosate was often capable of shifting the direction of two-species interactions, but there was little agreement between the different tests. Reanalysis of particle colonization data presented earlier demonstrated that glyphosate frequently eliminated negative associations between the same four species, possibly by acting as a resource. It is concluded that interactions between pairs of fungi can be influenced directly by glyphosate (especially at high concentrations) and that this may influence soil fungal community structure.

Wardle, D. A. and D. Parkinson (1992). "Influence of the Herbicides 2 4-D and Glyphosate on Soil Microbial Biomass and Activity A Field Experiment." Soil Biology and Biochemistry 24(2): 185-186

Witje, A. H. B. M. (1998). The Role of Tissue Nitrogen Content on Arundo donax Translocation Rates and Rhizome Growth. Arundo and Salt Cedar: The Deadly Duo, A Workshop on Combating the Threat from Arundo and Salt Cedar. C. E. Bell. Ontario, CA, University of California Cooperative Extension, Imperial County: 21-26 (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).

Zembal, R. (1998). Habitat for Threatened Habitat and Endangered Species: Quarantine Areas or Control Exotic Weeds? Arundo and Salt Cedar: The Deadly Duo, A Workshop on Combating the Threat from Arundo and Salt Cedar. C. E. Bell. Ontario, CA, University of California Cooperative Extension, Imperial County: 15-20 (http://teamarundo.org/ecology_impacts/Proc98/proc98_index.html).