agrichemical and environmental newsaenews.wsu.edu/april00aenews/apraenews00.pdf · environmental...

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Agrichemical &Environmental News

¿¿¿¿¿April 2000

No. 168

In This Issue

Comments to: Catherine DanielsWSU Pesticide Information Center

2710 University DriveRichland, WA 99352-1671

Phone: 509-372-7495Fax: 509-372-7491

E-mail: [email protected]

The newsletter is on-line atwww2.tricity.wsu.edu/aenews,or via the Pesticide InformationCenter (PICOL) Web page at

http://picol.cahe.wsu.edu

Hard-copy subscriptions are $15 ayear. Mail check to above address,ATTN: Sally O’Neal Coates, Editor.

Insecticidal Genes, Part 2:Human Health Hoopla ................. 1

Protecting Our Insect andMite Friends ................................ 8

8th Annual Food SafetyFarm to Table Conference ........... 9

The Value of Section 18s .......... 10

2000 Pesticide ContainerRecycling Schedule................... 11

The Chemistry of MothPheromones .............................. 12

Noteworthy New Products......... 14

Dear Aggie ................................ 15

PNN Update .............................. 16

Federal Register Excerpts......... 17

Tolerance Information................ 17

Whom Do You Trust?Transgenic crops have been goodfor publishers of both print andinternet media. Websites haveproliferated touting the various“truths” about genetically modifiedcrops, ranging the gamut fromsafety and benefits to lurkingcatastrophe. Printed books pro-claim fearful postures with titleslike Against the Grain: Biotechnol-ogy and the Corporate Takeover ofYour Food (5) and GeneticallyEngineered Food: Changing theNature of Nature (subtitled WhatYou Need to Know to ProtectYourself, Your Family, and OurPlanet) (14). Forwards penned bycrusaders like Ralph Nader destinethese books for the best-seller list.But should the man who told us notto buy the rear engine-mountedCorvair be trusted about thedangers of biotechnology?

Therein lies a big problem. Whoand what information do we trust todecide whether transgenic technol-ogy is safe? The books mentionedabove (which were actually copy-righted by environmental advocacygroups), as well as theGreenpeace website (4) areobviously against genetic engi-neering of food. But they do raisethe following legitimate concerns

Insecticidal GenesPart 2: Human Health HooplaDr. Allan S. Felsot, Environmental Toxicologist, WSU

about the short- and long-termsafety of transgenic crops:

u Possible production ofallergenic or toxic proteins notnative to the crop

v Adverse effects on non-target organisms, especiallypollinators and biologicalcontrol organisms

w Loss of biodiversity

x Genetic pollution (un-wanted transfer of genes toother species)

y Development of pestresistance

z Global concentration ofeconomic power and foodproduction

{ Lack of “right-to-know”(i.e., a desire for labelingtransgenic foods)

Legitimate Concerns,Testable HypothesesGreenpeace et al. argue thatthese concerns were not ad-dressed prior to commercializingand planting millions of acres oftransgenic crops, or, as the Euro-

...continued on next page

Agrichemical andEnvironmental News

A monthly report on pesticides and related environmental issues

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peans call them, GMOs (geneticallymodified organisms). But based onthe acreage of Bt transgenic cornand cotton planted in the UnitedStates (Figure 1), we and our live-stock have already been exposed totransgenic crops for at least fouryears, apparently without any healthproblems. Are we all just guineapigs? Or has the safety informationbeen available all along, but notaccessed by those concerned?

I can understand why many feeluncomfortable with GMOs. Thestudy of genetics in high schoolbiology classes was not a particu-larly pleasant experience. If youhaven’t followed the transformationof high school genetics into collegebiology and beyond to molecular biology, then trans-genic technology will seem simultaneously new, mira-culous, and overwhelmingly mysterious. The arcanejargon of molecular biologists makes their tricks oftrade inaccessible to all but ardent practitioners. Thus,genetic engineering seems remote and untested. Yetfor over twenty-five years we have had the capabilityto move genes from one species to another. Suchfeats grew in parallel with our understanding of how tomap gene locations on the chromosomes.

Nevertheless, the concerns posed by environmentaladvocacy groups are legitimate. To address thevalidity of these concerns, we must separate what istestable and what is sociological. In this essay Iaddress the question of whether Bt proteins can betoxic to humans and whether they can pose risks ofallergic reactions.

Something Old, Something New,Something BorrowedBt transgenic crops are considered “plant pesticides,”and they are subjected to the same battery of testsgiven to old and new chemical pesticides. Perhapson the surface, it looks as though the U.S. Environ-

mental Protection Agency (EPA) gave the majortransgenics producers the green light to commercial-ize their seed lines with just a cursory critique. But, infact, the risk assessment process was expedited bythe nearly forty years of positive experiences withcommercial Bt sprays.

The place to start with questions about the safety ofBt transgenic crops is with Bt itself. Bt is one of manymicrobial pesticides. Its formulated fermentationcultures can be sprayed on foliage to control selectedinsects because the ubiquitous bacterium synthesizesa toxic protein, known as the delta-endotoxin, everytime it stops growing and produces a spore. In 1998,the EPA compiled many years of collected data into are-registration eligibility decision document (RED) thatcovers all Bt products not produced by genetic engi-neering (17). The data overwhelmingly supported thesafety of Bt to humans and nontarget organisms.Certain Bt spray formulations are among the fewinsecticides certified for organic agriculture (19).

Over twenty years ago, scientists began to discovernumerous strains of Bt that were toxic to differentspectra of insects. More than fifteen years ago,

FIGURE 1Use of Bt transgenic corn and cotton in the U.S. (15)

Genes: Health Hoopla, cont.


Dr. Allan S. Felsot, Environmental Toxicologist, WSU

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molecular biologists began to identify the genescoding for the various insecticidal proteins character-istic of the individual Bt strains. Eventually theysuccessfully moved these genes across species linesand into production crops.

The insecticidal gene the molecular biologists movedinto corn, cotton, or potatoes is actually a truncatedversion of the natural gene. For the gene to functionin plant cells, small snippets of DNA are attached thatallow the code to be read. To track the location of thegene and help select plant cells that have success-fully incorporated the gene into their chromosome,marker genes encoding for either antibiotic or herbi-cide resistance are also spliced onto the toxic proteingene. The plant cells, however, do not activate theantibiotic markers. The herbicide resistance genespecifically confers protection to a naturally occurringbacterial amino acid called phosphinothricin, which isthe active ingredient of the commercial herbicideglufosinate.

Are Bt Transgenic CropsToxic to Humans?We have known for a long time that theinsecticidal proteins produced by thevarious strains of Bt are toxic only tocomparatively few species of insects byvirtue of the coincidence of the insectsspecialized gut physiology and shape ofthe proteins themselves. All other organ-isms, lacking these unique factors,tolerate Bt exposure without exhibitingsymptoms of injury. Indeed, high dosesof Bt that are fed, injected, or placed inthe air of laboratory rats are essentiallynon-toxic. Similarly, feeding rats highdoses of any of the purified insecticidalproteins causes no measurable toxiceffects (Table 1). For comparison, thetable shows how common substancesaround the house (table salt, caffeine,vitamin A, and the lawn herbicide 2,4-D)could cause illness at much lower dosesthan Bt proteins.

Controversy surrounds the potential for non-proteinchemicals to cause adverse effects after long-term(i.e., chronic) daily exposure. However, when proteinsare toxic, the effect is immediate (acute), nevercumulative (chronic) (11).

Despite the good news shown in Table 1, it might beargued that Bt sprays do not leave as much insecti-cidal protein as is present in a transgenic plant, inwhich every tissue makes large quantities of theprotein. Dose makes the poison, so how do we knowthat we just haven’t fed the rats enough protein tocause an effect? To answer this question, we need toknow how much protein we might be exposed to ifeating food made from transgenic corn.

Fortunately, the amounts of Bt protein in varioustissues of transgenic corn plants throughout thegrowing season have been measured and reported tothe EPA (16).

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The levels of Bt protein incurrently registered trans-genic corn hybrids rangefrom non-detectable quanti-ties (<0.005 micrograms pergram of plant tissue, µg/g) to4 µg/g. (Table 2. Note that,contrary to popular percep-tion, different tissues do notexpress the same amount ofprotein. For these calcula-tions we are referring to theedible component, the grain.)Using the highest amount ofprotein present in grain, wecan calculate the amount ofpopcorn needed to be con-sumed by a human two-year-old child to reach the highestdoses fed to rats. To reach ahuman-equivalent dose of5000 milligrams of Bt proteinper kilogram of rat bodyweight (mg/kg), a child wouldhave to eat 27.5 pounds ofpopcorn. Assuming every new video release isequivalent to one pound of popcorn, even a moviecritic can’t see that many movies in a day. In otherwords, the EPA justifiably declared the risk of a toxicreaction from Bt proteins as essentially nil.

Is the Bt Protein Allergenicto Humans?I found a very scary website the other day publishedby a group called STOP (Society Targeting Overuseof Pesticides) (13). In a four part “exposé” they useda combination of physician anecdotes, testimonials,and out-of-context statements from toxicology studiesto paint a very alarming picture of Bt sprays, despiteoverwhelming evidence of the safe use of Bt spraysfor over forty years (remember—it’s certified organic).STOP does, however, raise an important issue ofwhether some individuals are uniquely sensitive.Allergic reactions to proteins are not uncommon, butallergy has a well-defined etiology (i.e., biochemical

cause) that is quite distinct from toxicity .

It is clear from my interpretation of the STOP anec-dotes, that reports of illness following woodlandsprayings of Bt products have not been clinicallyconfirmed as toxicity, but could conceivably enter therealm of allergic reaction. (It is important to note that,because Bt sprays are formulated with other non-insecticidal ingredients [officially known as inerts] toease their delivery, adverse reactions are not neces-sarily a result of the Bt protein itself.)

A number of food proteins are definitively associatedwith allergenic reactions. Fortunately, we know quitea bit about the biochemical events associated withallergic reactions, as well as the kinds of proteins thatcause problems (6). First, an allergic responseshould be distinguished from toxicity. Toxicity is thecascade of reactions resulting from exposure to adose of chemical sufficient to cause direct cellular or

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tissue injury or otherwise inhibit normal physiologicalprocesses. Allergic responses are immune systemreactions resulting from stimulation of a specific groupof antibodies known as IgE.

Many food allergens are proteins that are fairly stableto digestion or only partially broken down (6). Theprotein or its fragments migrate across the intestinalwall and stimulate immune cells known aslymphoctyes. Lympho-cytes stimulate theproduction of the IgEantibodies that arespecific for each aller-gen (which is alsoknown as an antigen).Eventually, subsequentexposures to the anti-gens lead to release ofbiochemicals known ashistamines and prostag-landins. These chemicals, in an effort to protect thebody, cause smooth muscle contractions (for ex-ample, the gut walls), dilation of blood vessels, andconstriction of the lung bronchia. Such effects mani-fest as the typical allergic symptomsof respiratory distress, running noseand stuffiness, swelling, and skinrashes.

One way to determine whether foodproteins are allergenic is to determinetheir digestibility using mixtures thatsimulate the environment of thestomach with its acid pH and en-zymes. If a protein is unstable in thisenvironment after a short contact time,then it has no potential for allergenicity.Food allergens are almost always proteins, and onecommon characteristic among them is their stability todigestion, as well as to heat (as in cooking) (6).Furthermore, the amino acid sequence of allergenicfood proteins have been mapped out, and suspectedallergens can be compared for similarities in struc-ture. Finally, many protein allergens have a sugar

molecule attached to them while they are partiallytransformed in a reaction known as glycosylation.

With the exception of the cry9C-containing hybrid ofcorn, all transgenic Bt proteins are rapidly degradedby the stomach environment and are unstable whenheated (Table 1). The cry9C protein is stable tosimulated stomach conditions, but it is not glyco-sylated and has not caused any adverse effects

characteristic of immune system responsesin mammalian studies. Furthermore, nopart of its structure resembles knownallergenic proteins.

Immune System Responsesto Bt Sprays ExonerateTransgenic Bt ProteinsA recently published study showed thatfarm workers who picked vegetables thatwere sprayed with a commercial Bt formula-tion called Javelin exhibited positive re-

sponses to skin prick and antibody tests (2). The Btformulation is a fairly complex mixture containinglarge amounts of spores, intact delta-endotoxinproteins, residual amounts of fermentation medium,

bacterial cell wall debris, andvegetative (i.e., growing) Btcells.

The experimenters preparedthe Javelin in the laboratoryto separate water solublecomponents, the Bt spores,and the Bt endotoxin protein.They then subjected the farmworkers to skin prick tests,which are routinely used totest for allergic reactions to

foods or other substances. Only the Javelin extractsrepresenting the water soluble portions and thespores gave positive reactions. No significant posi-tive reactions were noted with the delta endotoxinproteins. Test-tube-type studies with the IgE antibodyconfirmed that only the water soluble extracts andspores gave positive immune system reactions.


Most Bt proteinsdegrade rapidly inthe stomach; whileallergens are stableto digestion.

If Bt proteins arenot toxic, couldthey be allergenic?Tests can helpdetermine this.



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The unique experimental design of the farm workerstudy allowed the authors to confidently conclude,“results of this investigation should partially allayrecent concerns about the occurrence of possibleadverse health effects in consumers after exposure totransgenic foods.” Furthermore, “it is unlikely thatconsumers would develop allergic sensitivity after oralexposure to transgenic foods (e.g., tomatoes, pota-toes) that currently contain the gene encoding this[the Bt] protein.”

Exposure to Bt Proteins MayBe AncientAs the number of acres farmed by certified organicpractices increases along with the acreage of Bttransgenic crops, no doubt we will be exposed to Btprotein. But transgenics or not, we already areexposed to Bt proteins. Indeed, our exposure may beancient as well as unavoidable. Studies of the naturalecology of Bt show it is abundant in the foliage ofnumerous plant species, and its presence in the soilmay result from washoff with rainfall (7, 12). Evenmore curious is the occurrence ofBt in stored grain that has notbeen specifically sprayed. Storedgrain is commonly infested bymoths and beetles that may besusceptible to naturally occurringBt. Exposure to Bt by organismsfeeding on the grain is confirmedby finding Bt spores in the feces ofbirds and rodents collected fromthe feed mill (8). Indeed, birds androdents have been suggested aspossible spreaders of the Btspores. A recent study from Canada indicated that Btcan be detected occasionally on produce in grocerystores when no known aerial applications have takenplace on the subject crops in the field (3).

Still, some people will be concerned about the ubiq-uity of the Bt transgenic protein in whole fields of cornor cotton. But would the amount necessarily be anydifferent than produced by applications of Bt spray?The mass of Bt endotoxin protein in a corn crop after

spraying one commercial product may approach 14grams per acre. The amount of protein in transgeniccrops could be as low as 1.5 grams per acre or ashigh as 21 grams per acre (Table 2). Thus, theintroduction of engineered protein into the environ-ment doesn’t seem to present an environmentalburden any different than a single Bt spray.

Conclusions About Bt andHuman HealthOne argument that Greenpeace uses to warn usagainst transgenic foods is that the genes beingtransferred come from sources that have never beenpart of the human diet. The ubiquity of Bt in theenvironment, and its presence on fresh unsprayedproduce and in stored grain suggests that we havehistorically been exposed to Bt proteins.

Greenpeace warns us by relating the story of aller-genic soybeans produced after being engineered witha gene from Brazil nuts that directed increasedsynthesis of the essential amino acid methionine (10).

But they do not emphasize thatthe researchers already knewthat Brazil nuts contained anallergenic protein. Indeed, thepurpose of the study was todetermine whether transfer of theBrazil nut gene to soybean wouldexpress a protein possessing thesame allergenic property. Theresearchers did not uncoveranything unexpected but provedthat transgenes from allergenicfoods are still functional. FDA

policy already mandates labeling of foods with genesfrom known allergenic foods (9).

I’m sure that Greenpeace staff bet that few internetsurfers will seek out and read the original scientificstudies they mention to validate their position. Butthey shouldn’t be surprised that contrary perspectivesabound among those who critically read the scientificliterature.


Bt’s ubiquity in theenvironment…suggests we havebeen exposed to itthroughout history.



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A perception exists that our regulatory system isbroken and the EPA cannot be trusted. Take it from arabid critic of EPA’s risk assessments that prior toregistering Bt transgenic crops, the agency alreadyhad in hand all of the studies addressing the healthissues raised by Greenpeace and others. In Part III,I’ll examine the remaining issues concerning environ-mental effects and resistance management.

Dr. Allan S. Felsot is an Environmental Toxicologistwith the Food and Environmental Quality Lab atWashington State University, and a frequent contribu-tor to AENews. He can be reached at (509) 372-7365or [email protected].

REFERENCES

1. Bernhard, K., and R. Utz. 1993. Production of Bacillusthuringiensis insecticides for experimental andcommercial uses. Pp. 255-267 in Bacillus thuringiensis,an Environmental Biopesticide: Theory and Practice, P. F.Entwistle, J. S. Cory, M. J. Bailey, and S. Higgs, ed. JohnWiley & Sons, NY.

2. Bernstein, I. L. et al. 1999. Immune responses in farmworkers after exposure to Bacillus thuringiensispesticides. Environ. Health Perspectives 107:575-582.

3. Capital Health Region, Office of the Medical HealthOfficer. 1999. Human health surveillance during theaerial spraying for control of North American gypsy mothon southern Vancouver Island, British Columbia, 1999. AReport to the Administrator, Pesticide Control Act, Ministryof Environment, Lands and Parks, Province of BritishColumbia (available at http://www.caphealth.org/btk.html)

4. Greenpeace. 2000. Genetically engineered food. http://www.greenpeace.org/~geneng/reports/food/

5. Lappe, M., and B. Bailey. 1998. Against the Grain:Biotechnology and Corporate Takeover of Your Food.Common Courage Press, Monroe, ME. 163 pp.

6. Lehrer, S. 2000. Potential health risks of geneticallymodified organisms: how can allergens be assessed andminimized? Pp. 149-155 in “Agricultural Biotechnologyand the Poor”, G. J. Persley and M. M. Lantin, ed.Consultative Group on International Agricultural Research,The World Bank, Washington, D. C. (available atwww.cigar.org).

7. Martin, P. A. W., and R. S. Travers. 1989. Worldwideabundance and distribution of Bacillus thuringiensisisolates. Appl. Environ. Microbiol. 55:2437-2442.

8. Meadows, M. P., D. J. Ellis, J. Butt, P. Jarrett, and H. D.Burges. 1992. Distribution, frequency, and diversity ofBacillus thuringiensis in an animal feed mill. Appl.Environ. Microbiol. 58:1344-1350.

9. Nestle, M. 1996. Allergies to transgenic foods—questions of policy. The New England Journal of Medicine334:726-728.

10. Nordlee, J. A., S. L. Taylor, J. A. Townsend, L. A. Thomas,and R. K. Bush. 1996. Identification of a Brazil-nutallergen in transgenic soybeans. The New EnglandJournal of Medicine 334:688-692.

11. Sjobald, R. D. et al. 1992. Toxicological considerationsfor protein components of biological pesticide products.Regulatory Toxicology and Pharmacology 15:3-9.

12. Smith, R. A., and G. A. Couche. 1991. The phylloplaneas a source of Bacillus thuringiensis variants. Appl.Environ. Microbiol. 57:311-315.

13. Society Targeting Overuse of Pesticides. 2000. Our caseagainst moth spraying. http://www.vcn.bc.ca/stop

14. Teitel, M., and K. A. Wilson. 1999. GeneticallyEngineered Food. Changing the Nature of Nature. ParkStreet Press, Rochester, Vermont. 175 pp.

15. USDA-ERS. 1999. Impacts of adopting geneticallyengineered crops in the U.S.—preliminary results. (http://www.econ.ag.gov/whatsnew/issues/gmo/

16. USEPA Biopesticide Safety Sheets available for eachregistration at www.epa.gov/oppbppd1/biopesticides/ai/plant_pesticides.htm

17. USEPA Re-registration Eligibility Decision DocumentsWebsite. 2000. (Bt RED available as PDF file). http://www.epa.gov/REDs/

18. Wolnik et al. 1983. Elements in major raw agriculturalcrops in the United States. 1. Cadmium and lead inlettuce, peanuts, potatoes, soybeans, sweet corn, andwheat. J. Agric. Food Chem. 31:1240-1244.

19. WSDA. 2000. 2000 Brand Name Materials List—Pestand Disease Control. http://www.wa.gov/agr/fsah/organic/BNML00-PestDisease.htm



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Protecting Our Insectand Mite Friends

Bad Bugs, Good Bugs, and IPMThink of insects and mites in an agricultural contextand you will think of pests—the (usually) small organ-isms that chew or suck the life out of crops, reducingquality and profits. But not all insects and mites areour enemies. Some bugs are most definitely ourfriends and we are increasingly recruiting them asvaluable foot soldiers in our battlesagainst their pestiferous cousins.

As this new century begins, the focusof crop pest management around theworld has shifted, and will continue toshift, towards reducing pesticideinputs. Already we have made greatadvances in this direction but thegreatest advances are likely yet tocome. Integrated Pest Management(IPM) has become the catch cry ofpest control specialists everywhere. Biological controlis usually a part of IPM systems. This is where ourfoot soldier bugs come in….

Biological Control: Two KindsBiological control of insect and mite pests is mostoften thought of in “classical” terms. Classical biologi-cal control involves importing an exotic predator orparasitoid to control an exotic pest. This is the kind ofbiological control that receives media attention. Thefirst and possibly most famous classical biologicalcontrol success involved the Australian cottonycushion scale insect, which threatened to destroy theCalifornian citrus industry early last century. Importa-tion of an Aussie beetle predator by American ento-mologists saved the day (and the industry).

However, most biological control is truly natural. Itoccurs without fanfare, often unobserved or unrecog-nized. This type of biological control is referred to as“conservation biological control.” The existence of asuccessful biological control system of this typesometimes is recognized only when somethingdisrupts it. Using a broad-spectrum insecticide (i.e.,one that kills ALL insects and mites, good and bad, ina crop) is often a good way of disrupting, thereby

exposing, a natural biological control system. Forexample, spider mites in many crops only becomesignificant pests when their predators are killed. Largepopulations of spider mites are rarely found in naturalor relatively undisturbed ecosystems like woodlandsor parks.

Good Health forGood BugsPreserving and encouragingbeneficial insect and mitepopulations inagroecosystems is a funda-mental component of IPM. Todo so, we need to know whichpesticides the beneficials cantolerate and which they can-not. Armed with this informa-tion, we can develop IPM

programs that are highly compatible with thoseinsects and mites most beneficial to a particular crop.

Pesticides: Determining theHazards for Good BugsAt present, very little information on tolerance tospecific pesticides is available for our beneficial bugsin Washington State. A new research program hasbeen established at Washington State UniversityProsser to fill this information void, at least for theapproximately twenty-five important beneficial bugspecies found in grapes and hops. Using laboratorybioassay techniques and procedures, researchers willexamine each species of beneficial insect and mitefor susceptibility to a range of commonly used pesti-cides (i.e., insecticides, miticides, fungicides). First,we will determine the toxicity of different pesticides topredators and parasitoids. We will also examinepossible sub-lethal impacts of pesticides (such assuppression of reproduction) on beneficials. We willconsider the possibility of positive effects of pesticideson beneficials as well. For example, a commonlyused insecticide in Washington, imidacloprid (tradenames: Admire, Provado) has been demonstrated toincrease reproduction in one species of predatorymite (James 1997).

Preserving andencouragingbeneficial insectsand mites isfundamental to IPM.

Dr. David G. James, WSU Entomologist


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Dr. David G. James, WSU Entomologist

Fungicides, the impact of which is often ignored, canalso affect beneficial bugs, particularly predatorymites. For example, the use of lime sulfur andmancozeb for disease control was once a majorimpediment to biological mite control in Australianvineyards. Substitution of fungicides determined to besafe to predatory mites, such as wettable sulfur,copper, and some synthetics, resulted in commer-cially acceptable biological control of mites (James1989, James and Whitney 1993, James and Rayner1995). Perhaps research on predatory mites in Wash-ington vineyards could result in a similar positiveoutcome.

Clearly, examining the individual susceptibilities ofnatural enemy species to different pesticides is anambitious program. However, it is one that is crucialto the effective development of IPM systems in hopsand grapes. We must learn more about the impacts ofall chemicals used in crops, on the good bugs as wellas the bad bugs. Armed with this information, we willbe able to more effectively recruit and utilize ourinsect and mite friends as allies in the ongoing waragainst crop pests.

Dr. David James is an Assistant Entomologist withWashington State University’s Irrigated AgricultureResearch and Extension Center (IAREC) in Prosser.He can be reached at [email protected] or(509) 786-9280.

REFERENCES

James, D.G. 1989. Effect of pesticides on survival ofAmblyseius victoriensis, an important predatory mite insouthern New South Wales peach orchards. PlantProtection Quarterly 4:141-143.

James, D.G. 1997. Imidacloprid increases egg production inAmblyseius victoriensis (Acari: Phytoseiidae).Experimental and Applied Acarology 21:75-82.

James, D.G. and Whitney, J. 1993. Mite populations ongrapevines in south-eastern Australia: Implications forbiological control of grapevine mites. Experimental andApplied Acarology 17:259-270.

James, D.G. and Rayner, M. 1995. Toxicity of viticulturalpesticides to the predatory mites, Typhlodromus doreenaeand Amblyseius victoriensis. Plant Protection Quarterly10:99-102.

8th Annual Food Safety ConferenceThe eighth annual “Food Safety Farm to Table Conference” will be held May 16 and 17, 2000, at the BestWestern University Inn in Moscow, Idaho. The conference is co-sponsored by Washington State UniversityCooperative Extension and University of Idaho Cooperative Extension System. Topics will include:

Foodborne Pathogens of current interest including Shigella and Listeria

Organics Issues including compost pathogens and the latest on federal organics regulations

Fresh Produce Safety including sprouts and water issues

Biotechnology and GMOs including an overview and the latest on safety

Registration fee is $150 before May 1, $175 after; preregistration is required. Fee covers all meeting ses-sions, luncheons, and refreshment breaks. For a conference brochure or further registration information,contact Chris Eder at (509) 335-2954 or [email protected]. Rooms at the conference hotel should bereserved by April 14; call (800) 325-8765 and ask for the Food Safety Conference special rate.

Protecting Our Friends, cont.

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In the February 1999 issue of Agrichemical and Environmental News, Washington State University’s Pesti-cide Information Center (PIC) attempted to summarize the value of Section 18s* to Washington agriculture.Using economic data from the Section 18 requests, we concluded that in 1998 alone, Section 18s wereworth $443.2 million to Washington’s agricultural industry. Dollar figures for Section 18s are typically com-prised of avoided crop losses but may also include savings associated with not having to replant or rehabili-tate acreage involved in severe pest infestations.

A year later, we find—not surprisingly—that Section 18s are still saving the industry money. The estimateddollar value of Section 18s issued in 1999 was $447.7 million, up $4.5 million from 1998.

While these numbers are interesting to compare and may even be impressive to toss around, be aware ofsome disclaimers:

u These are only estimates.

v If two Section 18s for the same use were issued in the same year, the estimated savingshas been “double counted.” (e.g., one Section 18 for Axiom DF on wheat was issued, with aMay 1999 expiration date; another for the same product and crop was issued later, allowingfor use into June of 2000.)

w PIC did not have usable economic data for every Section 18 request. Of the thirty-sevenemergency and crisis exemptions on the books at the end of 1999, five had insufficient datapertaining to acreage or specific net revenue to allow for a calculation.

x Where economic values were given as a range, the lower value was always used in thetotal estimated value.

Given those caveats, those of you who find this number useful or even interesting can track this informationon an ongoing basis via WSU’s Pesticide Notification Network web page. You can get there through thePICOL (Pesticide Information Center On-Line) web page at URL http://picol.cahe.wsu.edu/, or directly bygoing to URL http://www.tricity.wsu.edu/~mantone/pl-newpnn.html. Once on the PNN web page, clickon the Section 18 information and pull up the list for 2000. As we receive each Section 18 request, wecalculate and post the estimated value. When a Section 18 is issued as either an emergency exemption ora crisis exemption the value is then added to the annual running total at the top of the page.

What all this really means is that we should take a minute to thank the growers, commodity/commissiongroups, WSU research and extension staff, WSDA, and, yes, even EPA. The people who work processingSection 18s are making a significant contribution to Washington agriculture. And that’s no estimate!

Jane M. Thomas is the Pesticide Notification Network (PNN) Coordinator for the Pesticide InformationCenter (PIC) at WSU. She can be reached at (509 372-7493 or [email protected].

The Value of Section 18s

Jane M. Thomas, Pesticide Notification Network Coordinator, WSU

*ED. NOTE: For the uninitiated, a “Section 18” is a temporary exemption of a pesticide from the fullrequirement of registration in the case of an emergency circumstance. This exemption derives its nicknamefrom the section of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) that provides for it.

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¿¿¿¿¿April 2000

No. 168

Washington Pest Consultants Association

Washington Pest Consultants Association organizes an annual series of collection dates and sites for empty pesticidecontainers. The table below shows dates for April and early May only; watch upcoming AENews issues for more recyclingdates in the months ahead. A full schedule through October is available in the electronic version of AENews. Dates andlocations are subject to change; it may be wise to confirm with a telephone call before participating. Contact telephonenumbers for specific events are given in the table below. For general questions, or if you are interested in hosting an eventat your farm, business, or in a central location in your area, contact Northwest Ag Plastics representative Clarke Brown at(509) 965-6809 or David Brown at (509) 469-2550 or [email protected].

CONTAINERS MUST MEET THE FOLLOWING CRITERIA:• Rinsed—no residue remaining • Clean and dry, inside and out, with no apparent odor •

• Majority of foil seal removed from spout (small amount remaining on rim OK) •• Half-pint, pint, quart, one and two-and-a-half gallon containers accepted whole •

• Hard plastic lids and slip-on lids removed • Five-gallon containers accepted whole if lids and bails removed •• 30 and 55-gallon containers accepted whole if above criteria is met •

“Our industry does not want pesticide containers to become a waste issue. If we take the time to clean and recycle these products,we can save money, show that the industry is responsible in its use of pesticides, and reduce inputs to the waste stream.”

2000 Pesticide ContainerRecycling Schedule

ETAD EMIT NOITACOL ROSNOPS TCATNOC ENOHP

3lirpAa11-a8 ecurB tolpmiS azraGekiM 2312-884)905(

p3-p1 ollehtO lacimehCH&B ylwaHyrraL 6756-884)905(

4lirpA nooN-a8 harraH hcsuH&hcsuH hcsuHnellA 1592-848)905(

42lirpA a11-a9 ycniuQ lacimehCmraFycniuQ renruTnoR 6553-787)905(

1yaMnooN-a8 allaWallaW s'rogerGcM truByraG 7876-925)905(

p3-p1 grubstiaW s'rogerGcM yocaJyrreT 1266-733)905(

2yaMa11-a8 yoremoP ecivreSmraFnretseW yesliWyrreJ 1943-348)905(

p3-p1 notyaD s'rogerGcM ecurBffeJ 4074-793)905(

3yaM

a01-a8 ttocserP tsewhtroNirgA redlEnwahS 0788-745)905(

p2-a11 ttocserPdrahcrOs'ejteorB notlehSeoJ 7122-947)905(

hcnaRpoTtalF edvoHevaD 2869-745)905(

p5-p3 ocsaP carTriA sutiTdlareG 1035-745)905(

4yaMa11-a8 aipotlE sillErubliW droceRnreV 1924-792)905(

p3-p1 aipotlE .vreSyarpSaWnretsaE noxaMsilliW 7834-792)905(

5yaMnooN-a8 llennoC eraCporCR&B nesdliksEsirhC 1977-432)905(

p3-p1 ocsaP eraCporCretsifP retsifPevetS 4034-792)905(

8yaM p3-p1 elttaeS ecivreSeerTnotgnihsaW legnAnoR 0019-263)602(

9yaMnooN-a8

nonreVtnuoMskroWcilbuPtigakS euRaLniboR 0049-633)063(

p3-p1 ecivreSriAeladsnorT elsileBniveK 2240-166)063(

01yaM

a11-a8 drahcrOtroPytilicaFksiRetaredoMytnuoCpastiK

.tmgMtsePagemOnesialociNsleiN

tseBddoT1875-733)063(1354-373)063(

p4-p2 amocaT TOD&.oCsillE-rubliWnestunKydnaRnosrettaPevaD

1956-153)352(5527-985)352(

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¿¿¿¿¿April 2000

No. 168

In the “chemical soup” of the environment, insectsmust locate food and shelter, avoid being eaten,and—for obvious reasons—boy must meet girl. Formany lepidopterans (moths), success in finding amate is achieved through the female’s release ofattractant chemicals that prove irresistible to males ofher species. These attractant chemicals are known toscience as “sex pheromones.” The sex pheromonefor a female moth must be able to rise out from the“background stink” of competing odors and conveythe unambiguous message to males of her species,“I am here and I am ready for sex.”

Love is in the AirA female moth excretes pheromones in

the form of an odor cloud or “plume”that travels through the air carrying

its seductive messageas it evaporatesand dissipates.Typically, she willonly produce

and releasepheromones at certain

times of the day underspecific environmental conditions.

Release of pheromones during windy or rainyweather, for example, would prove unproductive.The shape and effective dispersal of the plume in theairstream is determined by factors including wind,temperature, vapor pressure, and topography.

Pheromone structures must remain fairly stable asthey move through the air. Large molecules can proveunstable and too heavy to volatilize, while small onescan dissipate too rapidly. In keeping with this objec-tive, moth sex pheromones have a very limited sizerange, containing between twelve and twenty carbons(see examples, Figure 1).

Love Potion Number NineWe know a great deal about the chemistry of sexpheromones. They are metabolically derived fromfatty acids. Codling moth pheromone’s main compo-nent is (E,E)-8,10-dodecadien-1-ol, a primary alcohol

The Chemistry of MothPheromones

consisting of a straight chain of twelve carbons withtwo conjugated double bonds. Other moth phero-mones contain molecules that differ substantially instructure; some are epoxides, acetates, or aldehydes(Figure 1). The codling moth pheromone, also knownas codlemone, is an excellent example of a success-fully synthesized pheromone with commercial applica-tion in mating disruption (see AENews Issue 159,“Codling Moth: Serious Pest Provides IPM Model.”)

Only YouOne might think that the female moths’ limited rangebetween twelve and twenty carbons for their phero-mone structures would result in interspecific sensitiv-ity among the thousands of moth species that releasepheromones—i.e., moths of various species beingattracted to one another’s pheromones. In fact,pheromone chemists have determined that manypheromones consist of blends of two or more volatilechemicals that need to be emitted in exactly the rightproportions to elicit the correct response from theappropriate male.

In addition to chemical structure differences betweenthe various moth pheromones, there are substantialdifferences between species in the release rates andactivity period of pheromones. For example, thecodling moth pheromone evaporates about 7.5 timesfaster than that of the Pandemis leafroller (Figure 1).

The Nearness of YouProximity is another factor in the success of phero-mone attraction. While a moth pheromone plume canbe huge, with detectable pheromones ranging fromyards to miles from the point-source female, concen-tration of the attractant does decrease with distancefrom the female. To be effective, the sexpheromone must persist at asufficient concentration whenit reaches the recipientmale moth to elicit aresponse.

In theory, thefemale silk moth

Dr. Douglas B. Walsh, WSU Entomologist


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¿¿¿¿¿April 2000

No. 168

Dr. Douglas B. Walsh, WSU Entomologist

Codling Moth Pheromone(E,E)-8,10-Dodecadien-1-ol

a.k.a. Codlelure; (8E,10E)-8,10-Dodecadien-1-ol;Codlemone; CheckMate Pheromone; Dodecadien-1-ol

C12H22OMolecular Weight 182.3052

Alcohol

OH

O

Silkworm Pheromone(E,Z)-10,12-Hexadecadienal

a.k.a. Bombykal


Aldehyde

OGypsy Moth Pheromone

(+/-)-cis-7,8-Epoxy-2-Methyloctadecane [29804-22-6]a.k.a. cis-7,8-Epoxy-2-Methyloctadecane;

7,8-Epoxy-2-Methyloctadecane;Disparlure; Oxirane, 2-decyl-3-(5-Methylhexyl)-,cis


Epoxide

O

O

Pandemis Leafroller Pheromone(E)-11-Tetradecenyl Acetate

a.k.a. (E)-11-Tetradecen-1-ol Acetate; Tetradecen-1-yl Acetate;Tetradecen-1-ol, Acetate, (E)-; Trans-11-Tetradecenyl Acetate

C16H30O2Molecular Weight 254.4118

Acetate

Chemical structures, synonyms, and molecular weightsof selected moth pheromones.

FIGURE 1

produces sufficient attractant to excite ten trillion malemoths. But environmental factors, release rate, andproximity must align if the excitation response is tooccur.

Come A Little Bit CloserFinding himself within the active space of a phero-mone plume, the male moth’s initial long-rangeorientation is though anemotaxis—movement into theprevailing wind. As he gets closer, the male mayorient himself toward the female by chemotaxis—movement toward the higher concentration of phero-mone.

Once the male is in close proximity to the female, andthe pheromone concentration has exceeded a thresh-old, genetically stereotyped responses are set in

motion. A cascade of behavioral courtship behaviorsbegins. If the female deems him worthy, copulationwill occur.

Next month, I will address the biological aspects ofsex pheromones. Male moths detect pheromones vianeural structures on their antennae called sensilla.These structures result in a marked difference inappearance, or sexual dimorphism, between malesand females in many moth species.

Dr. Douglas B. Walsh is an Agrichemical and Environ-mental Education Specialist with WSU’s Food andEnvironmental Quality Laboratory. His office is at theIrrigated Agriculture Research & Extension Center(IAREC) in Prosser, and he can be reached [email protected] or (509) 786-2226.

Moth Pheromones, cont.

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¿¿¿¿¿April 2000

No. 168

A number of new pest control products have been introduced over the past several years, many of which exhibit reducedrisk and may serve as viable alternatives for older pesticides. The partial list of herbicides below was compiled from theInterregional Research Project #4 (IR-4) Winter 2000 newsletter. A more complete product table, including more herbi-cides, plus insecticides, fungicides, nematicides, and plant growth regulators, can be seen in the electronic (on-line)version of this month’s Agrichemical and Environmental News at www2.tricity.wsu.edu/aenews. We will print excerptsfrom these tables in upcoming issues as space allows. Further details on individual products can be found on the IR-4website at http://www.cook.rutgers.edu/~ir4/. If you are interested in determining whether specific technologies couldmeet your crop protection needs, please contact me at (509) 786-2226 or [email protected].

Noteworthy New Products

Dr. Douglas B. Walsh, Washington State IR-4 Liaison

Herbicide Trade Name Crop Registrant Chemistry Pest Control Spectrum

alpha-metolachlor

DUAL MAGNUM

Registered: corn, beans, peas, potato, sorghum, onion, cabbage, peach. Pending: tomato, grass seed, sugar beets, carrot, spinach, rhubarb, asparagus. Potential: garden beets, turnip greens, gr. onion, broccoli, melons, caneberry, blueberry, pumpkin.

Novartis Chloracetanilide Same spectrum as metolachlor (DUAL)

BAS 615 H. BASF Isoindoldione It is particularly active post-emergence on Galium aparine, among other broadleaf species, in small grains

Beflubutamid UBH-820 Potential use on wheat, barley, rye, and triticale. Ube Industries Phenoxybutanamide Post-emergence control of broadleaf weeds

Carfentrazone-ethyl AFFINITY, AIM

Registered on field corn and wheat. Pending use on sorghum, potato, barley, sweet corn, and oats. Potential use on caneberry.

FMC Aryl triazolinoneNumerous broadleaf weeds, including cocklebur and water hemp.

Clodinafop-propargyl DISCOVER Pending registration on wheat. Novartis

Pyridylory-phenoxy propionate

Selective post-emergence of wild oats, annual grasses and other weeds

Dimethenamid FRONTIERRegistered on dry beans, field corn, popcorn, seed corn, and grain sorghum. Pending use on dry bulb onion and garden beets.

BASF ChloroamideAnnual grasses, broadleaf weeds, yellow nutsedge

Dimethenamid-P

FRONTIER X-2 Pending use on corn, potato, seed grass. BASF Chloroamide Annual grasses, broadleaf weeds, yellow nutsedge

Flazasilfuron MISSION Unknown status on grape. Zeneca & ISK SulfonylureaActive against many grasses & broadleaf weeds w/ pre- and post-emergence activity at 50 g/ha

Florasulam DE-570 Unknown status on wheat, barley, and oats. Dow AgroSciencesTriazolopyrimidine sulfonanilide

Provides post-emergence of broadleaf weeds, particularly Galium aparine

Fluazolate JV 485 Unknown status on wheat.Bayer and Monsanto

Pre-emergence control of broadleaf weeds and grasses

Flucarbazone-sodium EVEREST 70 WG Pending use on wheat. Bayer

Sulfonylamino-carbonyl-triazolinones

Manages wild oat and green foxtail, and certain broadleaf weeds

Flufenacet AXIOM Registered on corn and grass seed. Potential use on potato, tomato and onion.

Bayer Thiadizole or oxyacetamide

Soil applied for annual grasses and some broadleaf weeds.

Flufenpyr-ethyl S-3153 Pending registrations on corn. Potential use on snap bean, lima bean and dry beans.

Valent PPO Inhibitor Excellent control of velvetleaf and morning glories

Flumesulam BROADSTRIKE Registered on corn. Pending registrations on dry bean.

Dow AgroSciences Sulfonamide

Flumioxazin VALOR 50 WD Potential use on pome fruit, stone fruit, grapes, carrot and tomato.

Valent N-phenylphthalimide derivative

Controls pre-emergence broadleaf with contact activity and residual soil activity

Fluroxypyr STARANE FRegistered for wheat, barley, oats. Potential uses on spinach, tree crops, and bulb onion. Dow AgroSciences Picolinic acid

Post-emergence to control annual and perennial broadleaf weeds, including vol. Potato, Kochia and Nightshade

Flurtamone Unknown status on wheat, barley, oats and pea. AventisPre- and early post-emergence for control of annual broadleaf weeds and some grasses.

Glufosinate LIBERTY, RELYRegistered: apples, grapes, potatoes, field corn. Pending: sweet corn, canola, potato, sugar beet. Aventis Amino acid Broad spectrum, non-selective

Halosulfuron PERMITRegistered on field and sweet corn and grain sorghum. Pending use on cucurbits. Potential use on snap/dry beans, asparagus, and potato.

Monsanto/ Gowan Sulfonylurea Controls nutsedge, velvetleaf, cocklebur, and other broadleaf weeds

Imazamox RAPTOR Pending use on edible legumes, and canola. American Cyanamid

Imidazolinone Pre- and post-emergence control of annual grasses and broadleaf weeds.

Isoxaflutole BALANCE Registered on field corn. Pending use on sweet corn, wheat and barley.

Aventis Isoxazole Soil applied for many annual grasses and some broadleaf weeds

Mesotrione Pending use on field corn. Potential use on sweet corn.

Zeneca CyclohezanedionePre- and post- emergence management of annual grasses and broadleaf weeds, including sulfonylurea resistant weeds.

Oxadiargyl TOPSTAR 80 WP Potential use on vegetables and tree crops. Aventis Oxadiazol Broad spectrum weed control, similar to oxidiazinon

Quizalofop-ethyl

ASSURE Registered on canola, peppermint and spearmint.

Dupont Post-emergence grass herbicide

Pelargonic Acid

Registered on all crops. Dow AgroSciences Biopesticide Contact, non-selective

Pyraflufen-ethyl ECOPART Pending use on wheat and potato. Nihon Nohyaku Protox inhibitor

Post-emergence herbicide for general non-selective control of weeds or use as dessicant.

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¿¿¿¿¿April 2000

No. 168

Dear AggieProviding answers to the questions you didn’t know you wanted to ask

In contrast to the usually more sober contributors to the Agrichemical and Environmental News, Dear Aggie deals light-heartedly with the peculiarities that cross our paths and helps decipher the enigmatic and clarify the obscure. Questionsmay be e-mailed to Dear Aggie at [email protected]. Opinions are Aggie’s and do not reflect those of WSU.

Dear Aggie:

I ran across the following in the February 23,2000, Federal Register:

“This regulation establishes time-limitedtolerances for residues of the inert ingredient(herbicide safener) 3-dichloroacetyl-5-(2-furanyl)-2, dimethyloxazolidine, which is alsoknown as furilazole (CAS Reg. No. 121776-33-8) in or on corn commodities (grain, forage,and stover), at 0.01 ppm.”

If inert ingredients are so darned inert, why dothey need tolerances?

Inert Inquirer

Dear Inquirer:

A truly “inert” ingredient may not need a tolerance, butit might have one anyway. The reason can be found inCFR 40 Ch. 1 §153.125 (e):

Designation of a substance as a pesticidally inertingredient does not relieve the applicant orregistrant of other requirements of FIFRA withrespect to labeling of inert ingredients or submis-sion of data, or from the requirements of theFederal Food, Drug, and Cosmetic Act withrespect to tolerances or other clearance ofingredients. (emphasis added)

So, whether the registrant decided to apply for atolerance or EPA decided to require one, the resultwill be an inert ingredient with an established toler-ance.

That answers your direct question, but Aggie becamefascinated by an additional, implied question: “Whenis an inert not inert?” or “Are safeners necessarily

inert?” (If you weren’t implying that, no matter. WhenAggie becomes fascinated, it’s “in for a penny, infor a pound.”)

The crux of this matter is the definition of “inert,” asopposed to “active.” The Federal Insecticide,Fungicide, and Rodenticide Act (FIFRA) clearlydesignates an ingredient “active” if it has directpesticidal activity OR if it “has the ability to elicit orenhance” the pesticidal effect of another compound;in other words, if it’s a “helper.” A good example is thatcan of RAID® on your grocer’s shelf. Check the labeland you’ll see a potent combination—an activepyrethrin insecticide and its (non-insecticidal, buttechnically “active”) synergist, PBO (piperonylbutoxide).

Safeners are a special type of “helper” compound,acting to “safen” the activity of another compound sothat the latter can be tolerated by a subject crop. Forexample, thiocarbamate and chloroacetamide herbi-cides are registered for use on corn and sorghum butare actually toxic to them. Safeners are added to theformulation to help these crops break down the toxicherbicide faster. (The safeners themselves may havedirect herbicidal activity but only at very high doses.)It could be said that such safeners “elicit or enhance”the weed control effect of the primary compound.Interpreted thus, the law would consider safenersactive ingredients, not inerts. In this light, your originalquestion might have been whether the author of theFederal Register entry you cited was in error callingfurilazole an “inert.” Naturally, Aggie would not pre-sume to make that accusation, and is relieved thatwas not the question you asked.

(Reference: Code of Federal Regulations 40, Subpart G,section 153.125, Criteria for determination of pesticidalactivity; Devine et al. 1993, Physiology of Herbicide Action,PTR Prentice Hall)


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¿¿¿¿¿April 2000

No. 168

Dear Aggie:

I heard the other day that the USDA has passed some rules regarding organic agriculture. Seems tome that I heard this about two years ago. Aggie, I’m getting the sense of déjà vu all over again. Am Ilosing my memory?

Been Here Before

Dear Been Here:

Aggie can’t tell if you’re losing your memory, but you have certainly heard this news story before. The USDAAgricultural Marketing Service released the first proposed rules for a national organic standard on December16, 1997. The agency received 275,603 responses, an historical record. Nearly every response was ada-mantly against allowing, as the initial proposal did, the use of genetically engineered food, irradiation, andsewage sludge in organic agriculture and food processing. The second draft of the proposed rules eliminatesthese three bones of contention, with the interesting disclaimer by the USDA that there was no evidence of anyadverse effects from any of the three practices. The recently released rules can still be commented upon, butUSDA expects to have the final rule out by the end of the year. Who says the government doesn’t reflect thewill of the people? (http://www.ams.usda.gov/nop/)

Dear Aggie, cont.

from page 15

PNN Update

The Pesticide Notification Network (PNN) is operated by WSU's Pesticide Information Center for the Washing-ton State Commission on Pesticide Registration. The system is designed to distribute pesticide registration andlabel change information to groups representing Washington's pesticide users.

PNN notifications are available on our web page. To review those sent out in February, either access the PNNpage via the Pesticide Information Center On-Line (PICOL) Main Page, http://picol.cahe.wsu.edu/, or directly,at http://www.tricity.wsu.edu/~mantone/pl-newpnn.html.

We hope that this new electronic format will be useful. Please let us know what you think by submitting com-ments to Jane Thomas at (509) 372-7493 or [email protected].

Jane M. Thomas, Pesticide Notification Network Coordinator

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¿¿¿¿¿April 2000

No. 168

Federal Register Summary

In reviewing the February postings in the Federal Register, we found the following item that may be ofinterest to the readers of Agrichemical and Environmental News.

In the February 8 Federal Register, EPA announcedthat in accordance with an agreement reached withAgrEvo, the registrant is requesting both use dele-tions for its formetanate hydrochloride-containinginsecticides and some product cancellations. (Theproduct cancellations involve SLNs.) The proposeduse deletions cover plum and prune use, as well asgreenhouse grown ornamentals. (Page 6208)

In the February 11 Federal Register, EPA announcedthe availability of PR Notice 2000-1. This documentclarifies EPA's policy with respect to the applicabilityof the "treated articles exemption" in 40 CFR152.25(a) to antimicrobial pesticides. A copy of thisdocument is available electronically at the followingURL under the February 11 information: http://www.epa.gov/pesticides/. (Page 7007)

In the February 22 Federal Register, EPA announcedthat revised risk assessments were available foracephate and methamidophos. Electronic copies ofboth revised risk assessments can be accessed fromthe following URL: http://www.epa.gov/oppsrrd1/op/status.htm. Comments on these documents are dueto EPA on or before April 24, 2000. (Page 8702)

On October 21, 1999, EPA reopened the commentperiod on the proposed rule "Standards for PesticideContainers and Containment" to obtain comment onfour specific issues. On December 21, 1999, EPAextend the comment period by 60 days until February19, 2000. EPA is now reopening the comment periodfor an additional 30 days until March 20, 2000. (Page9234)

Tolerance InformationChemical Federal Tolerance Commodity (raw) Time-Limited(type) Register (ppm) Yes/No New/Extension Expiration Dateimidacloprid 16-Feb-00 pg 7737 0.20 sweet corn, fodder Yes New 31-Dec-01(insecticide) 0.05 sweet corn, grain

0.10 sweet corn, forage

zinc phosphide (rodenticide) 23-Feb-00 pg 8872 1.00 alfalfa, forage and hay Yes Extension 31-Dec-02

Comment: This time-limited tolerance is being extended in response to EPA granting a Section 18 for the use of zinc phosphide to control voles in California alfalfa. This action also amends the tolerance, raising it from 0.1 ppm to 1.0 ppm. The amendment is necessary

because the request is for a new use pattern.

imidacloprid to control flea beetles on sweet corn seed in Minnesota and Idaho. EPA has authorized the corn seed to be planted in states

Tolerance Information