Open Forum:
In an attempt to promote free and open discussion of issues, The
Agrichemical and Environmental News encourages letters and articles
with differing views. To include an article, contact:
Catherine Daniels, Food and Environmental Quality Laboratory, Washington State University, Tri-Cities campus, 2710 University Drive, Richland, WA 99352-1671. Phone: 509-372-7495. Fax: 509-372-7491.
E-mail:
cdaniels@tricity.wsu.edu
In This Issue
Enter this address carefully, paying close attention to punctuation and spacing (no spaces between parts of the address). Some readers may experience difficulties accessing the site. These are believed to be related to the Internet and to on-line services, not the web site. If you are having a problem accessing the web page, please inform Catherine Daniels (ph: 509-372-7495, fax: 509-372-7491, E-mail: cdaniels@tricity.wsu.edu
Clarification:
The May 22 meeting of the Washington State Commission on Pesticide
Registration, reported in the January issue as being in the WSU Extension
Office in the courthouse, will be held at the WSDA Pesticides Branch
Conference Room at 2015 S. 1st St. in Yakima.
This change in policy, particularly as it affected impending apple and pear
shipments from the Pacific Northwest, was achieved through the intervention
of U.S. Agriculture Secretary Dan Glickman and the efforts of the Foreign
Agricultural Service (FAS) and Animal and Plant Health Inspection Service
(APHIS) representatives in Bogota, Colombia.
According to the report, insecticide residues on grapes showed high degeneration rates soon after treatment, with half-lives ranging from 0.97 to 3.27 days.
Processing the grapes into wine caused considerable residue reductions (more than 80%) for chlorpyrifos, methyl parathion and quinalphos; moderate reduction (about 50%) for methidathion; and almost no reduction for fenthion. The two wine making techniques, with and without maceration, had the same influence on pesticide residue concentrations.
Food Chemical News, Nov. 27, 1995
Douglas Rothwell, minor use coordinator for Health Canada, participated in the meeting. Canada will cooperate in the 1996 IR-4 program and is scheduled for six field trials, which will be analyzed at IR-4 laboratories. Canada will analyze one group of IR-4 samples. The venture with Canada is part of the harmonization called for under the guidance of the US-Canada Free Trade Agreement. A total of 496 field trials for 1996 are distributed as follows:
| Northeast | 54 |
| Southern | 100 |
| Northcentral | 66 |
| Western | 92 |
| ARS | 178 |
| Canada | 6 |
| Total | 496 |
The bill is part of a legislative package moving through a special session of the California Legislature called into session by Gov. Pete Wilson to make enactment possible without the two-thirds vote required of urgency measures.
Unless long-awaited health impact studies are completed, suspension of
methyl bromide use takes effect March 30. An extension of the deadline was
sought by grower groups when it became apparent the studies would fail to
appear on time.
Pesticide RECERTIFICATION
Programs for Western
Washington
| Olympia | Feb. 28 |
| Silverdale | Mar. 4, 5 |
| Bellevue | Mar. 6, 7 |
Integrated Plant Health Workshop,
| Puyallup | Mar. 5-8 (5 credits per day) |
PRE-LICENSE Courses in Western Washington
| Olympia | Feb. 26, 27, 28 |
The free workshop will focus on how to apply for Section 18 emergency exemptions and Section 24(c) Special Local Needs registrations. No lunch is provided, but light refreshments are provided for the morning session.
Registration forms must be returned by March 8. These forms, directions and
more information may be obtained from WSDA Minor Crop Program coordinators
Michele Hauff at 509-575-2595, Robin Schoen-Nessa at 360-902-2027 or from
the WSDA Registration Branch at 360-902-2030.
| 8:00-8:15 | Registration |
| 8:15-8:30 | Introduction Ted Maxwell, WSDA Program Manager, Registration |
| 8:30-9:00 | Overview of Section 18 Process _ Explanation of a Section 18 review, time frames, and Section 18 definitions. _ Michele Hauff, WSDA Registration & Minor Crop Program Coordinator |
| 9:00-9:45 | EPA Perspective _ An overview of how EPA processes Emergency Exemptions, agency reviews, and how to improve submissions to speed review. EPA materials and information presented at October 1995 workshop will be presented. _ Robin Schoen-Nessa, WSDA Registration & Minor Crop Program Coordinator |
| 9:45-10:00 | Break |
| 10:00-11:00 | Data Generation - Choices _ Discussion of how to
meet Section 18 Exemption and 24(c) Registration research requirements. Discussion of WSU research programs, IR-4 Program and how the new Washington State Commission on Pesticide Registration can be an asset |
| 11:00-12:00 | Panel Discussion - Overview Section 18 Guidance Package & Problem Areas _ Discussion of the Section 18 process: The applicant's request submission to WSDA - WSDA's request to EPA - Successfully receiving an exemption; Challenges of past Section 18s and future proposals including industry/grower perspective. _ Robin Schoen-Nessa, Michele Hauff, & Rocky Lundy - Mint Industry Research Council |
| 12:00-1:30 | Lunch |
| 1:30-2:00 | Overview of SLN Process _ Explanation of a 24(c) request review, time frames, 3rd Party 24(c)s and the differences in WSDA and EPA roles _ Michele Hauff, WSDA Minor Crop Registration Coordinator |
| 2:00-3:00 | Panel Discussion - Overview 24(c) Guidance Package & Problem Areas _ Explanation of how a crop protection need/pest problem becomes a Special Local Need. Discussion of information needed to receive a successful 24(c) review. Discussion of challenges to receiving a 24(c), including an industry perspective. _ Robin Schoen-Nessa, Michele Hauff, & John Shipley - Asgrow Seed |
| 3:00-3:30 | Experimental Use Permits _ The importance of EUPs in generating data to support future registration needs. _ Steve Foss, WSDA Agricultural Chemical Specialist, Registration |
An EPA panel released a statement declaring that "the critical issue is not whether adequate alternatives for all methyl bromide uses are available now, but whether they will be available by the time the phase-out deadline arrives. EPA knows that it will be a combination of chemical and nonchemical methods that replaces the many uses of methyl bromide, not a single chemical." The panel also stated that eliminating methyl bromide "could reduce future atmospheric loading of ozone-depleting chemicals by 13%, making this the single most significant policy action that can be taken" to reduce risks associated with a thinning ozone layer.
In the European Community, the European Union Council of Ministers adopted a position favoring an accelerated phase-out of methyl bromide and hydrochlorofluorocarbons under the Montreal Protocol, in order to protect stratospheric ozone. These accelerated schedules would outpace existing law in the European Union, as well as timetables established under the international treaty.
The European Union Commission officials criticized recent U.S. congressional hearings as counterproductive to the need to hasten the phase-out of ozone-depleting chemicals. Commission officials said the U.S. hearings were especially damaging to efforts to get developing countries to phase-out exemptions on use and production of ozone-depleting chemicals.
The Commission stated that "this is extremely disappointing, because we certainly need the full support of the U.S., both the executive branch and the Congress on this issue. It is really hard to understand those who question the validity of the ozone issue. Certainly, these people are not scientists."
The December 7 Journal of Commerce reported that U.S. farmers are unlikely to succeed in having other countries ban use of methyl bromide by Jan. 1, 2001, the date when the fumigant is set to be phased out in the U.S. Growers claim they will be overrun with imported produce, if all countries do not ban the pesticide. The article says the farmers' problems reflect deep divisions within the administration, where USDA opposes any reduction in methyl bromide's use before 2001 and others are offering an earlier reduction to gain concessions. Farmers are expected to turn to Congress, where legislation is proposed to lift the ban's deadline until the secretary of agriculture determines either that an effective and affordable substitute to methyl bromide has been found or that a uniform international phase-out date has been set. The article notes support for the legislation by President Clinton and Sec. Glickman.
Chemical Regulation Reporter, Oct. 27 and Dec. 15, 1995.
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The article, "A Farming Revolution," starts with a legitimate and exciting notion that farming in the U.S. is changing and moving toward a more sustainable ideal. The author, Verlyn Klinkenborg, defines this as being agriculture that is "economically viable, environmentally sound, and socially responsible". However, the author co-opts this idea to promote the interests of "organic agriculture" and portray more "conventional agricultural" practices as ignorant and shortsighted. In doing so, the terms "sustainable agriculture" and "organic agriculture" are often confused, the facts about the farming practices used as examples are distorted, and a link between modern farming practices and the decay of rural communities is contrived. The limitations and risks associated with many of the practices hailed by the author are not recognized, and the benefits of many existing practices are ignored. His conclusion, based on a few examples of organic farming, is naive and seriously misleading. Not only does he play upon nostalgia to frame his premise that agriculture is rushing to organic farming, he also ignores the economic and social costs should such a "revolution" ever take place.
Early in the article, hoeing and cultivation are cited as means of weed control that do not rely on synthetic chemicals. Although these practices can be substituted for herbicide applications, they do not come without their own drawbacks. Large-scale adoption of hoeing and cultivation would cause more farm worker accidents, increase the use of petroleum, increase erosion, and require millions of laborers to return to the fields. Instead of the charming picture of the father and his sons, hoes at the ready, "marching to battle weeds," why not show the much less idyllic view of millions of black workers in the 1920s-1930s hoeing weeds out of Southern cotton fields? Synthetic chemicals to kill weeds substituted for millions of hours of drudgery in the fields.
Cultivation generally requires several passes over a field in a single growing season to obtain effective weed control. Herbicides often provide control for long periods of time and reduce the number of passes necessary to control weeds. Consequently, less time is spent by the growers operating dangerous farm equipment, and less fuel is consumed. Also, cultivation can increase soil erosion by continually disrupting the surface of the soil. The author does not mention the major reductions in soil erosion that have resulted as farmers have substituted herbicides for mechanical cultivation in control of weeds and adopted conservation tillage practices.
The picture of the Wisconsin farmer using a propane flamer is a great misrepresentation. Nowhere in the article does it point out the risk of operating a tractor with large propane tanks attached to it. The author writes that flame cultivators use only "a few gallons of fuel instead of oceans of herbicides." The comparison is not accurate. The chemical herbicides are typically used at rates of quarts per acre mixed into a hundred gallons of water. Use of fossil fuels is higher for the propane weeder versus the few grams, ounces or pounds of chemical herbicides applied per acre. Did the author watch or talk to pesticide applicators who accurately spread eight ounces of a chemical evenly over an entire acre?
The author misrepresents several facts in discussing organic agriculture. We understand that the Gallo winery's organic-trial, 15,000-acre vineyard noted in the article has since been returned to conventional farming methods supported by Integrated Pest Management. Purportedly, severe weed control problems, a drop in soil fertility and attendant costs of organic methods led to the decision. The article's picture of the Gallo vineyard clearly shows that cover crops were not being used between all the rows. How much water did the cover crops consume?
The article does not mention that organic farming operations typically use large amounts of pesticides that are certified organic. Often, these pesticides are used at much higher rates than synthetic compounds and don't work as well. Compounds of sulfur, and copper are regularly sprayed on organic grapes and potatoes to control diseases. The rise in the use of synthetic chemicals since World War II is also distorted. It is not mentioned that, prior to that time, growers used crude chemical compounds, such as lead-arsenic, cyanide gas, copper and sulfur to control pests. Synthetic pesticides replaced these chemicals, many of which were harshly toxic. The idea that growers obtained good yields, and maintained profitable farming operations without pesticides, was almost as untrue in the early part of this century as it is today. Although it may be true that his "granddad didn't use chemicals", certainly many growers of his generation did to control agricultural pests. What were his granddad's yields? In many cases, the amount of pesticide used decreased when synthetic chemicals were introduced. Coincidentally, yields of crops such as apples increased dramatically because the synthetic chemicals were less harsh on the trees and the environment than the lime sulfur and lead-arsenic previously used.
Dr. David Pimental's claims about percentage crop losses from pests being the same now as before the advent of modern pesticides are suspect and misleading. The true value of modern crop production technology, such as pesticide use, is reflected in crop yield. U.S. farmers produce four times as much per acre now than 50 years ago.
Many other modern farming practices are also distorted by the author. For example, the hybrid corn that he disdains for taking jobs and knowledge away from the farmer is largely responsible for the huge increase in corn yields in the last 40 years. Also, the use of fungicides to control diseases of corn is almost zero due to the continual development of resistant varieties of corn. The contour farming in Vernon County, Wisconsin, touted as revolutionary, is used by most growers in areas where erosion is a problem, especially on the hilly fields and light soils of southern Wisconsin. Farmers in this area regularly rotate corn with alfalfa, since both are used to feed livestock. Contour farming and rotations are farming practices widely adopted by all farmers, not just "organic" or "sustainable" ones. The use of manure as a source of nitrogen for the soil is also common, since livestock are present. However, this does not totally negate the need for fertilizer to be applied for other plant nutrients.
Certainly, one of the most important measures of success of any farming system is its profitability. Here again, the author misleads the readers that organic farming operations are as profitable as conventional operations.
One organic vegetable grower is quoted as reporting that she grosses $10,000 an acre from her vegetables. The article claims that this is far above the average for conventional crops. While strictly accurate, the statement is misleading _ the $10,000 per acre is not uncommon gross revenue for "wholesale" fresh vegetables. This amount is only greater than the average for conventional growers, because field crops, which garner a much lower price, are included in this average. Eastern lettuce growers typically receive $16,000 per acre for their wholesale lettuce (two crops per season), which then retails at $34,000 per acre.
A similar distortion is made in discussing organic rice production. The author refers to organic rice production in California with a somewhat favorable comparison of yields and costs of production. But he fails to understand that the organic rice field is only productive every other year. This is because weed pressure becomes so bad that the ground is kept fallow for an entire year, so that flooding and cultivation can be used to control the weeds. Therefore, the profitability of this farming operation is severely overstated. Organic growers who are profitable usually are so by taking advantage of the price premiums that their produce receives in the market place or by adopting very low input management practices that minimize inputs while sacrificing some yield. It is not accurate to say that organic agriculture can compete in the common market with other production methods.
Although the author points out a growing interest in sustainable agriculture and an increased awareness of environmental and community concerns in shaping farming practices, he uses them to promote a set of farming practices beset with its own problems, and to dispel many of the gains agriculture has made in the last 50 years. The new vision of farming he is searching for will be one of continual technological advancement, with the adoption of integrated pest management, precision farming, biotechnology, and the continued judicious use of synthetic chemicals for pest control. These advancements will reduce the amount of land needed to grow crops, keep people from the laborious and dangerous tasks of farming, and reduce the impact of pesticides on the environment.
U.S. farmers use hundreds of millions of pounds of synthetic chemicals every year. That is reality. Organic growers use pesticides, too, and often at higher per-acre amounts than do conventional farmers. The problem is pest control, not pesticides. Weeds, plant pathogens, nematodes, plant viruses, and insects are a constant threat to U.S. food production. Synthetic chemicals have reduced the risk of crop losses dramatically. The article, "A Farming Revolution," presents a distorted, naive view of the reality and future of U.S. agriculture.
Sincerely,
Leonard P. Gianessi National Center for Food and Agricultural Policy 1616 P Street, N.W., First Floor Washington, D.C. 20036
A. Richard Bonanno Bonanno Farm Trust 255 Merimack Street Methuen, MA 01844
Note:Leonard Gianessi is a senior research associate with the National Centers for Food and Agricultural Policy, a Washington, D.C. think tank on agricultural policy issues.
Richard Bonanno, on faculty at University of Massachusetts, operates a
diversified vegetable farm and serves on the IR-4 Commodity Liaison
Committee.
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The ability to detect pesticide residues at levels of parts per trillion has fostered the idea that water is highly contaminated with pesticide residues. Mere detections, regardless of quantity, are now perceived inherently as unwelcome risks. The fear of constant threats to human and ecological health from exposure to synthetic contaminants seems on the verge of overwhelming society. But, is there really a link between pesticide residue detections at environmentally characteristic levels and biological effects that justifies focusing attention on the very low levels found in water?
This question needs analysis from both human health and ecological health perspectives. Unfortunately, information about the health effects of exposure to agricultural chemicals has been derived from results of high dose exposures in acute and chronic toxicity testing. For example, in the joint WSU-WA Toxics Coalition publication, The State of Our Groundwater, readers learn that they risk exposure to a variety of chemical contaminants, but the accompanying tabulation of health effects information is based strictly on high dose feeding studies in rodents, not on environmental exposures.
The debate about health effects of exposure to residues in drinking water has been directed essentially by concerns of chronic toxicity, namely carcinogenicity. Herbicides are the most frequently detected pesticides in water systems throughout the U.S., and many of these compounds, including atrazine, have been labeled by the U.S. Environmental Protection Agency (EPA) as carcinogenic. As discussed in past issues of this newsletter, the whole system of carcinogenicity assessment has come under scrutiny. The biggest problem is testing carried out with maximum tolerated doses (MTD) administered over a rodent's normal two-year life span. But the National Academy of Science report, Issues in Risk Assessment, has pointed out that, although the MTD technique may currently be the only viable one to test carcinogenicity, the results are probably irrelevant to environmental exposures. Furthermore, given the current state of knowledge about the multi-step processes involved in the development of cancer, the EPA assumption of no-threshold for a carcinogenic effect has become archaic. Even the EPA is revamping its own guidelines for scaling the carcinogenicity of a substance, by incorporating more information from metabolic and physiologic (i.e., pharmacokinetic) studies.
To address whether there is a missing link between residue detection and biological effect, I will focus first on health-based risk assessments of atrazine. The USGS will soon be reporting numerous detections of this compound in Washington's surface and ground water; indeed, it will be the most frequently detected compound. The differences in perception about the risks posed by atrazine in drinking water can be highlighted by comparing the assessment by the environmental advocacy organizations, the Environmental Working Group (EWG) and Physicians for Social Responsibility, with that of Heidelberg College and Ciba-Geigy researchers who have been monitoring water quality in the Midwest.
The independently published EWG report, Tap Water Blues, purports to be a risk assessment of exposure to triazine and chloroacetamide (such as alachlor, metolachlor) herbicides in drinking water sources of the Midwest, where these compounds are used heavily on corn and beans. The total cancer risk associated with exposure was estimated by multiplying a routinely used cancer potency factor derived from high dose rodent studies by the average water concentrations. Although assumptions by EWG are basically the same as those used by the EPA, they present the risk as multiples above the "federal standards for acceptable cancer risk", which is nominally "one additional cancer per million exposed individuals." Using this benchmark, EWG reaches the alarming conclusion that "3.1 million individuals in 23 cities with populations over 25,000 are exposed to cancer risks from herbicide contaminated drinking water that exceed federal cancer standards by a factor of 10 or more." The 23 cities were in Illinois, Missouri, Iowa, Ohio, Kansas and Nebraska.
The Heidelberg College/Ciba-Geigy (HC) collaborative report was published in Environmental Science and Technology (ES&T). The researchers' risk assessment focused solely on atrazine exposure to total populations in Ohio, Illinois and Iowa. They segregated herbicide residue data and population exposure by type of drinking water source, because sources like groundwater and large lakes tend to have significantly lower pesticide concentrations than rivers. The benchmark of risk was the EPA health advisory level (HAL) designated for atrazine. The HAL is the pesticide concentration in drinking water at which health effects would not be expected to occur from lifetime exposure. The atrazine HAL of 3 ppb represents the No Observed Adverse Effect Level (NOAEL) estimated from animal tests as adjusted by a 5,000-fold safety factor (i.e., 1/5,000 times a water concentration of 15 ppm). The authors of the study concluded that less than 0.25% of the assessed populations was exposed to concentrations exceeding the HAL. Although EWG lumped all herbicides together, assuming the additive effect is biologically reasonable, atrazine levels still comprise nearly 50% of the average residue. The Heidelberg College focus on atrazine thus gives valid information for extrapolating risk assessment to exposures from all herbicides.
My perspective on the potential risk of consuming atrazine-contaminated water was derived from combining HC and EWG report data and focusing on the HAL as a safety benchmark. When 0.25% of the population of the reported six Midwestern states was exposed to atrazine levels exceeding the HAL, then 3,100 individuals, rather than 3.1 million (a 1,000-fold difference), may have increased health risks. But, recall that the HAL is 5,000 times less than the safe level as determined from the NOAEL. Even the highest atrazine concentration exceeding the HAL (13.5 ppb) reported in the HC study was 1,000 times less than the NOAEL. Thus, exposure assessment data suggest that no one is exposed to residues that have a biological effect.
Further evidence of an absence of human health effects from atrazine exposure in drinking water comes from a review of atrazine epidemiology published recently in Reviews of Environmental Contamination and Toxicology. The author concludes that epidemiological studies of individuals occupationally exposed to atrazine showed no increased incidence of cancer. Furthermore, the author also states that epidemiological studies of farmer exposure and incidence of cancer were too inconclusive to reliably prove a link between atrazine and carcinogenicity. Bear in mind that the exposures in these epidemiological studies would be thousands of times the exposures in drinking water.
In addition to human health effects, new concerns are being voiced about the effects of pesticide residues on aquatic organisms. The benchmark currently used for safety is the 96-hour LC50 determined on the most sensitive aquatic organisms (usually a crustacean or insect). The toxicity estimate is divided by a factor of 100, to calculate an ecologically based water quality criterion. Thus, residues below the criterion would be considered to have no adverse effect on the most sensitive species. None of the herbicide detections being reported for surface waters in Washington exceeded the ecological safety criteria. An aquatic risk assessment for atrazine was published recently in Environmental Toxicology & Chemistry. The assessment concluded that atrazine "does not pose a significant risk to the aquatic environment."
Although many may agree about the lack of adverse biological effects from atrazine and other herbicides, the outcome of an ecological risk assessment for insecticides is less certain. Chlorpyrifos, diazinon and azinphos-methyl are of primary concern, with chlorpyrifos dominating the number of detections in the USGS database. These organophosphorus insecticides have the highest toxicities to fish and aquatic invertebrates. The chlorpyrifos ecological water quality criterion is 0.04 ppb (or 40 ppt). Some of the detections that the USGS will report for Washington are above this level. For the following reasons, however, it would be wrong to interpret these detections as hazardous. First, the specific level detected is important; in Washington the highest level in the USGS database (0.120 ppb) is only three times higher than the water quality criterion. Second, the safety criteria are close to the analytical limit of detection, which makes residue numbers close to this level unreliable. Third, hazard could only be characterized if we knew how long the exposures lasted and how they fluctuated over time. Fourth, the toxicity bioassays do not use natural waters that contain dissolved organic matter. Numerous studies have shown that organic matter in water can significantly reduce toxicity. Finally, if the chlorpyrifos data are eliminated from the USGS database, insecticide detections in state waters are infrequent.
Despite 25 years of water quality funding to identify problems and develop best management practices, agricultural chemicals are still detected in aquatic systems. I believe now that ever lower detection limits will continue to yield detections, despite our best attempts to keep the chemicals on the farm. But the issue is not detections; the real issue should be biological effects. As shown in this essay, different researchers report different assessments of potential biological impacts, especially for human health. One can take the same set of pesticide residue numbers and obtain two entirely different perspectives.
I believe the uncertainty in risk assessments of very low levels of pesticide
residues is analogous to a phenomenon known from analytical chemistry. For
the analysis of any chemical in a sample of water, soil, plant, etc., the
closer the concentration is to zero, the more unreliable the result and the
more likely two different laboratories will report different results. Could
it be that the myriad of studies about the biological effects of exposure to
trace concentrations of pesticides in water produce contentious risk
assessments, because the concentrations are effectively close to that point
where there is no biological effect? If so, then perhaps we actually know
more than we think we do.
Note:Allan Felsot is an environmental toxicologist at the Food
and Environmental Quality Laboratory.
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Proposals are due by March 7, 1996. The WSCPR will decide in its next meeting which proposals to fund. That meeting is scheduled for March 20 at the WSU Tri-Cities branch campus. For more information on how to submit a proposal, contact Catherine Daniels at 509-372-7492.
Synopsis of the Request for Proposals: Proposals must originate from the affected pesticide user community. The requests may come from an individual, company or organization on behalf of a particular user community. Project requests should be limited to five single-spaced pages, not including budgets and attachments, and should state who will conduct the work, their qualifications and the time frame for project completion. Names, addresses and phone numbers of individuals involved in submitting and conducting the work should be included. Any project that involves generation of pesticide residue data in support of a registration must include provisions for use of Good Laboratory Practices (GLP), if appropriate. Although multi-year proposals will be accepted, funding will be provided for no more than one year at a time. Projects should address crop protection needs of importance to Washington and the Pacific Northwest.
Although proposals are not required to include matching support, applicants are encouraged to provide matching funds, in-kind services or materials for laboratory studies and investigations.
Description of Problem: Each proposal should contain a brief description of the affected industry and a detailed description of the pest problem. This should be done using any of the following appropriate criteria: per acre/unit impact, including potential monetary losses if appropriate; acres impacted; aggregate impact to the industry; effect of the pest problem on the industry; effect of the pest problem on consumers, society, environment, non-target species or human health; and description of why alternative control measures are not effective, or any additional information on the specific need.
Criteria: Proposals will be judged by the following criteria: relevance to stated WSCPR areas of emphasis; overall merit and quality of proposal: feasibility of completing project objectives within stated time frames; appropriateness of requested budget and adherence to WSCPR guidelines.
Areas of Emphasis:
The WSCPR will consider proposals dealing with pest control problems that
1) have an adverse economic impact to a user community or local economy;
2) pose some risk to human health or 3) pose adverse risks to the
environment.
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There is much information in the three fact sheets. Space remaining in this edition of the AENews does not permit a thorough review of the studies; one may expect such a review in the next edition. Following is a basic overview of the studies.
USGS sampled several wells in the Quincy and Pasco subbasins for pesticides; it checked 573 wells throughout the basin for nitrates and then checked two dryland streams (Palouse River and Upper Crab Creek) and two irrigated waterways (Crab Creek Lateral and EL68D Wasteway). The USGS invested a considerable amount of resources into the study, screening a large number of samples for a wide array of pesticides.
There is some good news and some not so good news. First, the good news: although many different kinds of pesticides were found in the surface water, none were at a level EPA considers unsafe. Forty-five pesticides or degradation products were found, with the most commonly detected products being atrazine (AAtrex), DCPA (Dacthal), simazine (Princep), EPTC (Eptam), metolachlor (Dual), terbacil (Sinbar), alachlor (Lasso), metribuzin (Sencor), 2,4-D, triallate (Far-Go), chlorpyrifos (Lorsban), trifluralin (Treflan) and pendimethalin (Prowl). As one might expect, the greater amounts of pesticides were found in the more intensively farmed, irrigated agricultural areas.
No registered pesticides were found in ground water at levels EPA considers unsafe. Twenty-three pesticides or degradation products were found, with the most commonly detected products being atrazine (AAtrex), an atrazine breakdown product, 1,2-dichloropropane, metribuzin (Sencor), and metolachlor (Dual).
Now, the bad news. EDB (ethylene dibromide) was detected in three wells at concentrations ranging from just below the maximum contamination level to over 20 times the MCL. EDB is a discontinued soil fumigant that was once used widely in the Basin. While the presence of the compound at 20 times the MCL may not pose a risk to human health, this is a pretty high level from the point of view of a concerned public.
Nineteen percent of the 573 wells tested for nitrates were above EPA's MCL for the chemical. Although consumption of water containing nitrates may not pose a risk to humans, the occurrence of nitrates at such high levels points to a need to refine crop production and protection practices.
Note: For more information on the USGS studies of agricultural
chemicals in the ground and surface waters of the Columbia Basin,
contact Sandy Williamson at USGS at 206-593-6530, ext 235 or by E-mail
at
Congress amended FIFRA in 1988, mandating that all pesticides registered
before November 1984 be subject to reregistration. The intent was to ensure
that 'old' products like 2,4-D meet current regulatory standards...that
their potential benefits outweigh potential risks, based on current criteria.
DowElanco, AGRO-GOR, Nufarm USA, and Rhone-Poulenc formed a task force in
1988 to coordinate and share the costs associated with developing the data
required by the reregistration process. The task force identified 270 new
studies that would be required to reregister 2,4-D. These included 54
studies on environmental toxicity, 60 on toxicology, 78 on environmental
fate, 68 on residue, and 10 on chemistry. Thus far, the task force has
submitted 174 studies to EPA; the remaining studies _ on chronic toxicity,
field dissipation, and crop residue _ were due to be submitted to the agency
by the end of 1995.
A summary of the task force work completed during the initial eight years of
testing was presented recently at a one-day seminar in Chicago. It was stated
that the studies to date haven't raised any major red flags relative to human
health and wildlife. Results show that 2,4-D is not linked to genetic damage
or tumor induction, or to reproductive or developmental problems. The task
force believes that 2,4-D, with its low toxicity and low dietary exposure,
will meet the "no unreasonable adverse effects" criterion written into FIFRA.
The cost for these studies: $25 million.
But there is still a fly in the ointment that EPA and the task force will
have to address during the decision making process. During this eight-year
period, the National Cancer Institute and others have raised a number of
epidemiological questions on the possible link between 2,4-D and
non-Hodgkin's lymphoma among farm workers. Non-Hodgkin's lymphoma (NHL) is
not a single disease but a group of diseases that are considered disorders
of the immune system. NHL occurs infrequently (15 cases per 100,000).
Epidemiological evidence from National Cancer Institute (NCI) studies in
Kansas, Nebraska, and Iowa/ Minnesota has been analyzed in detail. While the
Kansas study (1986) is often cited as showing a relationship between
frequency of 2,4-D use and non-Hodgkin's lymphoma, the actual question asked
in the study pertained to the frequency of herbicide use _ not 2,4-D use _
among farmers who indicated they had used 2,4-D. In other words, the use
frequency of 2,4-D, specifically, was neither asked nor determined.
In the Nebraska study (1990), data gathered by proxy (others answering on
behalf of farmers) indicated greater risks than did data derived from farmers
themselves.
In the third NCI study, Iowa/Minnesota (1993), no increased risks were
observed between frequency of 2,4-D use and non-Hodgkin's lymphoma.
Furthermore, under the Freedom of Information Act, the task force was able
to show that when the data were separated by source of information _proxy
respondents versus farmers _ proxy responses once again indicated higher
risks associated with 2,4-D use than did those of farmers. In another study
conducted by investigators at the University of Minnesota, similar findings
were observed: indications of risk were seen to increase only when proxy
respondents were used. This epidemiological phenomenon is called recall bias
and, by virtue of such bias, risks indicated in proxy interviews should be
considered invalid. When farmers themselves are asked specifically about
2,4-D use, there appear to be no recall differences, regardless of whether
these farmers have non-Hodgkin's lymphoma.
Finally, the epidemiologists and toxicologists indicated that six different
expert panels have reviewed the association between 2,4-D and non-Hodgkin's
lymphoma. All have arrived at essentially the same conclusion: 2,4-D does
not cause NHL. The most recent EPA-appointed panel, the Science Advisory
Board, wrote in March 1994, "...our conclusion at this time is that, while
there is some evidence that NHL may occur in excess in populations...exposed
to 2,4-D, the data are not sufficient to conclude that there is a cause and
effect relationship between...exposure to 2,4-D and NHL. The data are,
however, sufficient to require continued examination of the issue through
further studies."
The stage is set for 2,4-D to enter the decision phase of the reregistration
process. EPA should render its reregistration decision on 2,4-D by 1997, in
a document called the Reregistration Eligibility Document (RED). The RED
will contain EPA's answer regarding the eligibility of reregistration, the
rationale for their decision, and the need for additional data.
It is believed that the data package for 2,4-D will be as complete as for
any pesticide product, old or new. One thing for sure is that the 4,000
peer-reviewed toxicology studies in a collection of 40,000 should provide
sufficient evidence on which to base benefit-to-risk assessment. EPA's
decisions will be scrutinized by all parties interested in seeing 2,4-D
reregistered for use, as well as by those who believe this old herbicide
should be removed from the marketplace.
Source: Reprinted from the Label, Purdue Pesticide Programs newsletter,
January 1996
**EPA is evaluating the risks and benefits of the corn soil
insecticides. The Environmental Fate and Effects Division is proposing that
EPA cancel the four most widely used organo-phosphate insecticides:
chlorpyrifos (Lorsban), terbufos (Counter), fonofos (Dyfonate) and phorate
(Thimet) on corn.
**Both the state Senate and House on February 14 released proposed
budgets that included full funding for the Washington State Commission on
Pesticide Registration. This would seem to indicate that both houses and
both political parties are in agreement that WSU should receive the $1
million needed to support the commission.
**The USGS is conducting a study of pesticides in the ground and/or
surface waters of the Puget Sound. It will be a study somewhat similar to
the Columbia Basin studies. Although farther from implementation, USGS will
also conduct a similar study in the Yakima Valley.
**The Washington State Commission on Pesticide Registration plans to
hold a minor crop plant protection tour in the last half of July 1996. The
purpose of the tour will be to highlight critical crop protection needs of
Washington minor crops. The target audience for the tour will be pesticide
manufacturers and registrants. The three-day tour, to be based in Pasco,
will cover dryland and irrigated crops in the Columbia Basin, Yakima Valley,
Walla Walla Valley and Horse Heavens Hills. Attendance will be limited to
40 individuals and will be by invitation only. Event coordinators are Ann
George, Alan Schreiber and Jerry Baron (national coordinator of the IR-4
Project).
**Those interested in submitting a proposal to the WSCPR, should get
their proposals in to the commission as soon as possible. Although
commissioners did not set a limit on how much funding they would provide, it
is possible that as much as $250,000 to $300,000 could be spent on projects.
Questions about proposal preparations or deadlines, may be directed to
Catherine Daniels at 509-372-7492 or Alan Schreiber at 509-372-7324.
How It Works:
Comply does not work the same as conventional insecticides. What can be
unsettling to growers is that treated adults are not killed by Comply and
they continue to lay eggs. Instead of killing the adult pear psylla,
treating them with Comply causes overwintering adult females to lay sterile
eggs while they are in contact with treated surfaces. Additionally, few of
the eggs laid by females ever hatch if they are laid on treated surfaces.
Eggs that are laid before the application of Comply may or may not hatch
depending on how developmentally advanced the eggs were prior to the
application. Under laboratory conditions at room temperature, eggs that were
laid 72 hours or more before a Comply application were able to hatch
normally. Eggs younger than 72 hours were killed. This 72-hour window will
likely be longer under cooler field conditions. Nymphs from eggs that do
hatch encounter residues of Comply as they move about the tree and usually
die as first instar (very young) nymphs. Survivors after first instar
usually die as they molt to the adult form or molt into deformed and
dysfunctional adults. Complete evaluation of the success of pre-bloom
control can be done as soon as final molt is completed in early to mid-May.
How To Use It:
Washington State University recommends one to two applications of Comply
25WP, using 8 oz. of the product per acre each time. When two applications
are made, these should be applied at delayed dormant and again at cluster
bud. The label allows application in 50 to 400 gallons of water per acre.
Some growers and consultants have been using a single application of Comply.
This approach may be particularly appropriate when psylla populations are
low. Research at the Southern Oregon Experiment Station in Medford and at
the USDA-ARS in Yakima showed that a single application at the delayed
dormant timing was more effective than a cluster bud application. However,
other tests in the Pacific Northwest have shown no differences in pear
psylla control when these two timings were compared. Single applications
made at true dormant timing were relatively ineffective. If only a single
application of Comply is used, Everett Burts, formerly of the WSU Tree Fruit
Research and Extension Center in Wenatchee, suggests adding Thiodan
(endosulfan) to Comply to reduce adult psylla populations and provide some
level of control for pear rust mite. There is uncertainty about the need for
a true dormant (Stage 0) application for pear psylla control, if Comply will
be used at delayed dormant and/or cluster bud. Research done in Medford
showed that, when no dormant treatments were used, there was no significant
difference between a single delayed dormant application and the recommended
two spray program (delayed dormant and cluster bud). In Wenatchee, when 3
qts. of Thiodan and 4 gals. of oil per acre was applied at the dormant timing
and 8 oz. per acre of Comply used at the delayed dormant and cluster bud,
the two spray program reduced pear psylla populations more than a single
delayed dormant application.
Effect on Non-target Pests and Beneficials:
In research by Everett Burts at Wenatchee, Comply had less detrimental
effects on beneficials than did pyrethroid-based programs. Comply allowed
greater survival of predatory mites and predaceous bugs. Work by Pete
Westigard in Medford also showed that elimination of pyrethroids from
pre-bloom spray programs resulted in fewer mite problems. Pear rust mite can
build to high levels in orchards treated solely with Comply. Additionally,
use of acaracides may be necessary to control spider mites, because Comply
does not affect these pests. Growers should work with their consultants to
monitor these pests during the growing season. Some pear growers using Comply
had greater difficulty with leafrollers. Comply is effective against
leafrollers and may provide suppression or control of this pest, but the
proper timing for pear psylla control may not be adequate for leafroller
control. D'Anjou pear growers who are using the two spray program must also
consider the need for powdery mildew control, if they omit Morestan
(oxythioquinox) from the cluster bud spray. In handgun plots at Wenatchee,
Morestan was compatible with Comply.
Comply is toxic to larval bees, but doesn't harm adult bees. Experiments in
Europe showed that Comply can kill and deform bee larvae and pupae when
sprayed on apples during full bloom. Because of this, WSU has listed Comply
in the category "do not apply to blooming crops or weeds."
When 4-6 day old bee larvae were fed pollen and/or honey contaminated with
Comply, they developed into pupae with characteristic white streaks in their
compound eyes. This symptom of pupal damage and mortality will appear as soon
as 10 days after treatment. At times, deformed adults will emerge. Comply
sprayed during full bloom resulted in about 23% mortality of the brood. This
mortality occurred over a seven day period. In Holland, spraying apples with
Comply just before bloom resulted in some bee mortality, which is surprising.
Normally, no bloom means no bee kill.
Follow the label and don't apply Comply when pears are blooming. Eliminate
bloom on the orchard floor and margins before spraying. Help prevent bee
kills.
For additional information, contact:
John Dunley
Dan Mayer
*Key
Alan Schreiber, Allan Felsot, Catherine Daniels, Mark Antone,
Carol Weisskopf, Eric Bechtel
If you would like to include a piece in a future issue of the Agrichemical
and Environmental News or subscribe to the newsletter, please contact Catherine Daniels.
Contributions, comments and subscription inquiries may be directed to:
Catherine Daniels, Food and Environmental Quality Laboratory, Washington State University, Tri-Cities campus, 2710 University Drive, Richland, WA 99352-1671. Phone: 509-372-7495. Fax: 509-372-7491.
E-mail:
cdaniels@tricity.wsu.edu
Return to Table of Contents
The status of 2,4-D
The U.S. Department of Agriculture registered 2,4-D in 1947 as the first
selective agricultural herbicide to control weeds without damaging crops.
Its use in agriculture continues to expand, as reduced tillage gains
popularity. Due to 2,4-D's low cost and its efficacy against many weed
species, it's a 'perfect' herbicide and has found its way into weed
management programs involving rights-of-way, turf, aquatics and forestry.
Available Reports
Return to Table of Contents
Officially Unofficial
"Officially Unofficial" is a regular feature that may include information
considered inappropriate by some.
**Telone will be taken out of EPA Special Review soon. No
registrations for the product will be lost; however, there were will be
additional restrictions on how the product can be used. Many of the
restrictions on the federal label will be similar to those put in place
recently by the state of California. Additional personal protective
equipment and increased buffer zones are two types of new restrictions.
Return to Table of Contents
Comply for overwintering adult pear psylla control
What It Is:
Comply (fenoxycarb) has been labeled for use prior to bloom on pears under a
Section 18 exemption to control overwintering pear psylla adults.
Manufactured by Ciba, it is the first insect growth regulator-type
insecticide cleared for comprehensive use on any tree fruit in the Pacific
Northwest. Because of the unique properties of insect growth regulators,
Comply requires a change in thinking about using and evaluating pre-bloom
pear psylla control materials.
Mike Willett
Yakima County Coop. Ext.
128 N. 2nd Street, Rm. 233
Yakima, WA 98901-2631
509-575-4218
WSU Wenatchee
1100 North Western Ave.
Wenatchee, WA 98801
509-663-8181
WSU Prosser, IAREC
24106 N. Bunn Rd.
Prosser, WA 99350-9687
509-786-9233
Return to Table of Contents
Federal Issues
Tolerances
The following tolerances were granted by EPA since the last report
(January 1996). These data do not mean that a label has been registered
for this use. These pesticides must not be used until a label is registered
with EPA or a state department of agriculture.
A=adjuvant D=desiccant
D/H=desiccant, herbicide F=fungicide FA=feed additive
G=growth regulator H=herbicide I-insecticide N=nematicide
P=pheromone V=vertebrate repellent
Chemical* Petitioner Tolerance
(ppm)
Commodity
(raw)(A) jojoba oil Amvac exempt in or
on all raw
agricultural commodities when applied at not more
than 1% of
the final spray
tank adjuvant in accordance
with good agricultural
practices.(F) propiconazole IR-4 0.1
mushrooms 0.3 mint, tops (leaves and
stems)(I) chlorpyrifos DowElanco 0.05
nectarines, peaches,
pears, plums
EPA revokes food additive regulation
EPA is revoking the food additive regulation (FAR) for residues of the
herbicide trifluralin in peppermint oil and spearmint oil. EPA is taking
this action because peppermint oil and spearmint oil are not ready-to-eat
commodities, and residues of trifluralin are unlikely to concentrate in
ready-to-eat foods containing peppermint and spearmint oil. Therefore, this
FAR is not required.
Emergency Exemptions (Section 18)
A specific exemption has been granted for the following use:
Return to Table of Contents
State Issues
Special Local Needs (Section 24c)
Label restrictions for Special Local Needs in Washington: The following
pesticide use has been granted label registration by the Washington State
Department of Agriculture under the provision of Section 24(c) amended FIFRA.
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Contributors to the Agrichemical and Environmental News:
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