strawberry pest management strategic plan (pmsp

1. This document is CIR 1443, one of a series of the Pesticide Information Office, Food Science and Human Nutrition Department, Florida CooperativeExtension Service, UF/IFAS. For additional Information, contact the Pesticide Information Office, University of Florida, P. O. Box 110710,Gainesville, Fl 32611-0710, (352) 392-4721. Published February 2004 Please visit the EDIS Web site at http://edis.ifas.ufl.edu

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Employment Opportunity - Affirmative Action Employer authorized to provideresearch, educational information and other services only to individuals and institutions that function without regard to race, creed, color, religion,age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For information on obtaining other extensionpublications, contact your county Cooperative Extension Services Office. Florida Cooperative Extension Service / Institute of Food andAgricultural Sciences / University of Florida / Larry R. Arrington, Dean.

2. Mark A. Mossler, Pest Management Information Specialist. O. Norman Nesheim, Ph.D., Professor and Pesticide Coordinator, Pesticide InformationOffice, Food Science and Human Nutrition Department, Cooperative Extension Service, UF/IFAS, Gainesville, 32611-0710.The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warrantythe products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitablecomposition. All chemicals should be used in accordance with directions on the manufacturer's label.

CIR 1443

Strawberry Pest Management Strategic Plan (PMSP)1

Mark A. Mossler & O. Norman Nesheim2

Table of ContentsPage

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Mites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Insects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Nematodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Weeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Birds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Strawberry PMSP List of Attendees . . . . . . . . . . . . . . . . 9

Table 1. Efficacy ratings for pest management toolsagainst invertebrate pests in Florida strawberry. . . . 11

Table 2. Toxicity of pest management tools to beneficialsin Florida strawberry. . . . . . . . . . . . . . . . . . . . . . . . 16

Table 3. Indications for disease management productsused on Florida strawberries . . . . . . . . . . . . . . . . . . 19

Executive Summary

Florida ranks second in the U.S. in the productionof strawberry, providing 15 percent of the total U.S.crop, and 100 percent of the domestically-producedwinter crop. In 1999-2000, 220,500,000 pounds offresh berries valued in excess of $167 million wereproduced on 6,300 acres ($26,500/acre). There were6,900 acres of production reported in 2002. Over thelast 15 years, Florida strawberry growers haveincreased their acreage 40 percent and theirproduction volume 70 percent, while income hasincreased 300 percent. Because of the great value ofwinter strawberries and the high competition on eitherend of the production window, this crop is highlyintegrated in all aspects, especially pest management.However, the future loss of methyl bromide is the

Archival copy: for current recommendations see http://edis.ifas.ufl.edu or your local extension office.

Strawberry Pest Management Strategic Plan (PMSP)

February 2004

largest IPM consideration for this production system.Secondary pests (such as thrips) and emerging pests(such as whitefly and aphids) do exist for Floridastrawberry producers. Additionally, resistance issues(generally for miticides but also noted for a herbicide)exist in this production system. PMSP membersexpressed confidence that these issues may well beaddressed by a combination of research, education,and regulatory actions.

Research

1. Continued examination of new chemistriesthat address gaps in pest management(resistance, efficacy, or selectivity).

2. Assessment of cover crops for nematodemanagement.

3. Examination of current pest practices onvertebrate feeding deterrence.

Education

1. Education of growers/scouts with regard topest identification and sanitation, especiallyon transplants.

2. Education of growers/pest managers withregard to new application methods andresistance management of new chemistries

Regulation

1. Continue processing ongoing requests forregistration (methyl iodide, pyridaben,buprofezin, nicobifen, pyrimethanil, andsulfentrazone).

2. Determine if data exists that would allow PHIand plant-back interval modification forseveral management tools.

3. Interact with registrant/state agency to obtainstate registration of clopyralid (Stinger®) instrawberry with existing data.

Introduction

Florida ranks second in the U.S. in the productionof strawberry, providing 15 percent of the total U.S.crop, and 100 percent of the domestically-producedwinter crop. In 1999-2000, 220,500,000 pounds offresh berries valued in excess of $167 million wereproduced on 6,300 acres ($26,500/acre). There were6,900 acres of production reported in 2002. Over thelast 15 years, Florida strawberry growers haveincreased their acreage 40 percent and theirproduction volume 70 percent, while income hasincreased 300 percent. Approximately 95 percent ofFlorida’s commercial strawberry production acreageis located in Hillsborough and Manatee counties withthe remainder in several other counties in both northand south Florida. For this reason, a Pest ManagementStrategic Plan (PMSP) meeting for the Floridastrawberry industry was conducted at the FarmBureau office in Hillsborough County (Valrico),Florida.

Because of the great value of the crop as well asthe initial investment, it has historically beenrecommended that Florida strawberries be grown onlyon full-bed plastic mulch, and that a multi-purposefumigant be applied to the bed as the plastic is laidover it. Therefore, strawberries are grown as anannual crop in Florida using the hill (raised bed)system, with two to four rows of plants per raised bed.Methyl bromide, in combination with chloropicrin, iscurrently applied approximately two weeks prior toplanting transplants for the management of soilbornediseases, nematodes, insects, and weeds. A singleapplication at an average rate of approximately 140 to180 pounds of product per acre is injected into the soilduring construction of the raised-beds. Row middlesare not treated. The bed is then immediately coveredwith plastic mulch.

Several principal varieties are cultivated inFlorida and these varieties can change yearly. Toavoid re-introduction of mites, nematodes and otherpathogens to the treated beds, growers are encouragedto use only the best quality transplants available.Transplants are set in late September through earlyNovember. Drip and overhead irrigation is used tohelp establish plants and protect them from frost.Following early vegetative growth, the cool nights



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and short days of winter stimulate the plant toproduce flowers which, after pollination, develop intofruits ready for harvest in four to six weeks. Thisresults in three or four crops of fruit from each plant(based on a 30-day cycle). Flowers are present onplants in production areas continuously from shortlyafter planting until the end of harvest, but there aretypically two peak flowering periods each season, onein November or December, and the other in mid tolate January. The average harvest period runs fromlate November through early April. Fruit areharvested by hand every two or three days throughoutthe harvest season. Due to the frequency of harvest,preharvest intervals (PHIs) and restricted entryintervals (REIs) are important factors when growersselect pesticides for use on strawberries. Pesticidesare applied exclusively by ground applicationequipment. Florida’s warm, humid climate is ideal forthe development of many insect and mite, nematode,disease, and weed pests. Additionally, birds cansporadically become severe economic pests byconsumption and damage of the strawberries. All ofthese pests were discussed at the Florida strawberryPMSP meeting.

Mites

Spider mites of the family Tetranychidae(especially two spotted spider mite) are always themain mite pests, and cyclamen mites (familyTarsonemidae) are a sporadic mite problem.Transplants that arrive in Florida have been growingin northern fields (generally Canada or NorthCarolina) for months and have been exposed tovarious pest pressures. These producers try their bestto provide pest-free plants, but many newerchemistries registered for field use on strawberry arenot available to nurseries. Florida growers areencouraged by extension specialists to monitor thetransplants upon receipt for mites as well as aphids,immature whiteflies, and diseases. Once the conditionof the transplants is understood, growers shoulddecide to seek healthier transplants or prepare forpesticidal treatment after overheadwatering/establishment ends.

The establishment period (approximately threeweeks) when bareroot transplants are being irrigated

overhead is the first period of pest management andFlorida strawberry growers have very few chemicaloptions because the irrigation water washes off theactive ingredient. Consequently, any pest problemsare often chemically unmanaged until theestablishment period has ended. During this period,mites and lepidopteran larvae are the key arthropodpests. Lepidopteran larvae that were small uponarrival of the transplants are mature by the timeestablishment ends, and uncontrollable by B.t. spraysat that point. Consequently, mature larvae are oftentreated with methomyl, even though methomyl is notcompatible with a predatory mite program. It is nothard to see that initial transplant pest pressures set thestage as to whether a grower can use a beneficial miteprogram, as well as the entire mite/insect managementprogram for the growing season. However,registration of spinosad on strawberry in 2002 hasprovided growers with a product that is less toxic topredatory mites than methomyl at roughly the samecost per acre.

It was also noted by growers that weaker plantsare infested by mites more quickly than strongerplants. The economic threshold for spider mites ispresence of any life stage on five percent of theleaflets. In terms of chemical miticides, abamectinwas being used (and possibly overused) just prior tothe registration of bifenazate and hexythiazox. Somegrowers were reporting resistance to abamectin. Thesethree active ingredients now make up the core of thespider mite chemical management system, althoughsome growers not using predatory mites usebifenthrin and fenbutatin-oxide as miticides. Eventhough there appears to be many options for mitemanagement, it should be noted that seasonalapplications are limited to one for hexythiazox, two ofbifenazate or fenbutatin-oxide, and four of abamectin.

Before the introduction of bifenazate andhexythiazox, when abamectin sensitivity was beingquestioned, Florida strawberry growers had anestimated 40 percent adoption of predatory miteprograms. With the introduction of the new miticidechemistries, that rate has dropped to 30 percent, eventhough the two systems were roughly the same cost asreported by growers in attendance. Growers reportedthe desire to have “clean plants” rather than thosewith mites on them. Although predatory mite



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populations can withstand a few applications ofcertain insecticides (malathion, diazinon) over theseason, one of the biggest impediments to thepredatory mite program is that the liquid formulationof captan (used exclusively because the WPformulation leaves white residue) is toxic topredatory mites. Since captan is the backbone of theprophylactic fungicide program, it is a certainty thatpredatory mites will be sprayed and may be reducedto non-efficacious levels by these sprays.Thiophanate-methyl was also reported by growers tobe detrimental to predatory mites.

The growers also expressed regret that anextension publication (Berry Times) produced byUF/IFAS Hillsborough County Extension Office hasrecently been expanded to include vegetables, butalso minimalized with respect to technical advice forstrawberry growers. The growers did demonstrateinterest in having this publication “reinflated” forstrawberry growers to include more “forward-looking” advice.

For strawberry miticides, there are no carbamate,organophosphate, carcinogen, PHI, or REI concernswith the currently registered materials. Pyridaben ison the second quarter work plan for EPA’s FY 2004.Acequinocyl, a miticide receiving reduced riskchemical classification status, is a candidate forregistration during the second quarter of EPA’s 2004work plan. Etoxazole received a tolerance forstrawberry in September, 2003.

Insects

The three lepidopteran larvae that were reportedas pests in the crop profile (Spodoptera frugiperda, S.eridania, Helicoverpa zea) were confirmed bygrowers as the main “worm” problems, with“budworm” (H. zea) as the most damaging. These aremainly early season pests, and the ramifications oftheir presence during establishment have already beendescribed. Mid- and late-season insect pests includethrips, aphids, and sap beetles. Sap beetles are a zerotolerance pest. Presence of larvae in a ripe strawberrycan lead to rejection of the whole shipment.

For those growers employing predatory mites,B.t. and spinosad are the preferential materials for

“worm” management so that predatory mitepopulations are conserved. For those using exclusivechemical control, methomyl, spinosad, and bifenthrinare often used. Growers expressed desire to transitionaway from methomyl, as the restricted status carriesregulations with regards to licensing andrecordkeeping. Similarly, there are other insecticideswhich may be phytotoxic due to strawberry variety,temperature, or incompatibility with other activeingredients. These active ingredients are: carbaryl,dicofol, naled, propargite, oils (petroleum and neem),soaps, and sulfur. Perhaps the best example of this isfor petroleum oil and captan/sulfur. In this case, theuser is cautioned not to use oil in combination with orimmediately before or after spraying with captan orany product containing sulfur. Statementsdiscouraging sulfur use within four weeks of an oilapplication are also common on oil products.Consequently, growers face these constraints whendeciding an insect spray program.

As strawberries begin to form on the plants,chemical cues radiate to surrounding natural areas.These cues attract adult sap beetles of mainly twodifferent genera that deposit their eggs preferentiallyin rotting strawberries, although a few may bedeposited in fresh strawberries. The most importantsteps to take to manage sap beetle problems is to pickall fruit as soon as they mature and not leave behindany fermenting fruit. In addition to giving pickersincentive (money) to pull the rotting fruits, the fruitshould also be taken out of the field. The second bestpractice is to drop them into the row middles, wherethey decay too quickly for the beetles to completetheir life cycle. The pressure from sap beetles is mostintense during the last month of production, whenpicking is most intense. The five active ingredientsused to control sap beetle are bifenthrin, diazinon,pyrethrins, carbaryl, and malathion. But bifenthrinand pyrethrins can be hard on predatory mites, andthere are potential phytotoxicity issues with carbaryl,so diazinon and malathion are used more than theothers for sap beetle control. However, the PHI fordiazinon is five days and the PHI for malathion isthree days. Since the picking is done at two dayintervals, growers expressed desire to have a PHI oftwo days for both diazinon and malathion.

During the last month of picking is also a time inFlorida when oak and citrus blooms are concluding.Flower thrips move from these locations into the



February 2004

strawberry fields. However, it has also been notedthat the beneficial six-spotted thrips is present insubstantial numbers in Florida if the insecticidalspray program is not too “hard.” Consequently, aneffort should be made to educate growers regardingthe differences between these two thrips groups(beneficial or pest). When flower thrips do becomeproblematic, spinosad or methomyl is used. The newtolerance for imidacloprid on strawberry may provideanother tool for flower thrips control once it isregistered in Florida.

Aphids (strawberry and melon) have recentlybecome more persistent in localized areas than theyhave been historically. The presence of aphids andtheir cast skins and sugary excretions on fruit areobjectionable to consumers and reduce quality of thefruit. Although there are several aphid predators inFlorida, the most effective is a parasitic wasp. Aswith the six-spotted thrips, “hard” chemical programscan reduce the level of parasitism and allow aphidpopulations to increase. Growers wishing to reduceaphids before naturally occurring predators andparasites have done so must rely on insecticides. Anumber of materials are efficacious on aphids, such asdiazinon, malathion, methomyl, naled, azadirachtin,Beauveria bassiana, bifenthrin, and endosulfan.

A potential emerging insect problem is whitefly(usually greenhouse whitefly). The biggest concernfor Florida strawberry growers is that plant materialfrom California will harbor the inoculum for majoroutbreaks in Florida similar to those now occurring inCalifornia. Consequently, Florida growers utilizingmaterial from California should be educated on howto scout transplants for all whitefly life stages.

For strawberry insecticides, there are nocarcinogen or REI concerns with the currentlyregistered materials. As mentioned, growersexpressed desire to have a 2-day PHI for malathionand diazinon. The malathion IRED is scheduled forFY 2003 and perhaps the PHI change can beaddressed at that time. One concern in terms of IPMmay be that there is only one efficacious compound(spinosad) for mature worms that will not drasticallyharm predatory mites. Pyridaben is on the thirdquarter work plan of EPA’s FY 2003,methoxyfenozide and thiamethoxam are on the thirdquarter of EPA’s 2004 work plan, and rotenone and

pyrethrins still have to go through tolerancereassessment. Buprofezin (for whitefly management)is an A priority on IR-4's 2002 Food Use Workshoplist.

Nematodes

This arena of Florida strawberry pest managementis in the greatest turmoil due to the phaseout ofmethyl bromide. The methyl bromide replacementquestion is an entire multi-year program in itself, andthe critical use exemption process has clouded thepicture, as this program may or may not make limitedquantities of methyl bromide available beyond thecurrently scheduled phase out date. At this point,growers have been resigned to pay dearly for methylbromide as the quantity produced becomes less, or trythe best alternative strategy currently available, whichis viewed as an initial application of 1,3-dichloropropene and chloropicrin followed by asubsequent application of chloropicrin in combinationwith napropamide and oxyfluorfen as herbicidepartners, applied directly to the bed top immediatelyprior to the plastic laying operation. The members ofthe PMSP meeting believed that approximately ten to15 percent of growers would try using this alternativein 2003. This replacement is available because theregistrant just recently provided the EPA with datathat helped in reducing the PPE requirements forapplying 1,3-dichloropropene. Additionally, theformer 300-foot buffer zone has been reduced to 100feet. Application advances have also helped make theuse of 1,3-dichloropropene/chloropicrin a potentialpartial replacement for methyl bromide, exclusive ofweed control. One remaining constraint of this systemis that a minimum of 21 days must pass beforeplanting versus ten to fourteen days with methylbromide. Time is a critical component whenprofitability comes during a few weeks of harvest. Experimental work is continuing with othercompounds such as iodomethane and metam sodium.Research with azadirachtin and Myrotheciumverrucaria (Ditera®) have demonstrated these to benonefficacious in field conditions.

In addition to the nematodes that are resident inFlorida soils, there are also nematodes present on thetransplant tissue received at the beginning of the



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season. Regardless of source, the main pests are stingnematode and root-knot nematode. Work withnematode-suppressing cover crops such as sunn hemphave been initiated, but sting nematode seems to bequite mobile in the soils. Results have shown initialreductions, but sting nematode populations risequickly when feeding opportunities (strawberry roots)are present.

For strawberry nematicides, there are nocarbamate, organophosphate, carcinogen, or REIconcerns with the currently registered materials withthe exception of the methyl bromide phaseout.Iodomethane (methyl iodide) is on the second quarterwork plan of EPA’s FY 2003, and methyl bromidemust go through tolerance reassessment.

Diseases

The key diseases reported by growers at thePMSP meeting were those listed in the crop profile,namely Botrytis (gray mold) and Colletotrichumdiseases (anthracnose, fruit rot, and crown rot). Otherproblematic and emerging diseases include angularleaf spot, powdery mildew, and Phytophthoradiseases.

Botrytis attacks strawberry fruit in all stages ofdevelopment in the field and in transportation. Yearsin which conditions are cool and wet during the majorbloom period (mid-January to mid-February) provideexceptional disease pressures on Florida strawberries.Thankfully, several new chemistries have beenintroduced to help manage this fungus and growersreported utilizing all of them (cyprodinil +fludioxonil, fenhexamid). However, the backbone ofthe prophylactic fungus control program is therotation and use of captan and thiram. This isillustrated by the 2002 NASS survey data, whichreported a conservative average of 9.5 applications ofcaptan and 4.1 applications of thiram.

One of the characteristics of the newer materialsfor disease control are extensive label limitations. Allof the new compounds mentioned above (as well asazoxystrobin and pyraclostrobin) have fourapplication limits per season. Azoxystrobin,pyraclostrobin, and fenhexamid are not to be used

more than twice in a row without switching to analternative mode of action. The registrant forazoxystrobin and cyprodinil + fludioxonil (Switch®)has also obtained labeling for each of these as a dipfor the transplants, so one of the foliar applications inthe field will now probably be lost to a dipapplication. There is also a 12-month restriction onplant back for the mixture of cyprodinil andfludioxonil. Growers made it apparent that this plantback limitation restricts the use of this material, asmany of them would like to cultivate a quick-growingcrop such as a cucurbit after the strawberry pickinghas terminated. So it is apparent that growers have alimited number of applications of the new and muchcostlier fungicides. They view these as supplements tothe backbone spray program.

There are three species of Colletotrichum fungusthat affect Florida strawberry production,Colletotrichum fragariae, C. gloeosporioides, and C.acutatum. Fruit and root rot are generally caused byC. acutatum. Crown rot can be caused by the othertwo species. In fact, crown rot was the disease that ledto the demise of the strawberry nursery industry inFlorida. The strobilurin fungicides have shown to bemost effective in managing anthracnose fruit rotprophylactically. However, there was consensusamong meeting members that growers were uncertainas to the number of applications that could be madesince limitiations are either prescribed on a season,crop, or yearly basis. Having a new dip label may alsoconfuse growers as to the number of field applicationsthat can be made.

Angular leaf spot is caused by the bacteriumXanthomonas fragariae. Transplants often arriveinfected from the nursery. Cold, wet conditions(including overhead sprinkling for establishment orfreeze protection) encourage disease outbreaks.Copper fungicides and hydrogen peroxideapplications help to suppress this pathogen.

Powdery mildew is a sporadic/emerging fungalproblem. The disease is typically managed with fallapplications of myclobutanil or thiophanate-methyl.However, thiophanate-methyl cannot be used by thosegrowers using predatory mites, and resistance tomyclobutanil is suspected by members of the PMSPmeeting. Consequently, some growers are going backto sulfur for management, and others are having good



February 2004

success with potassium bicarbonate. Triflumizole hasalso been newly registered for management ofpowdery mildew in strawberry.

Two Phytophthora species (P. cactorum and P.citricola) occasionally cause crown rot and leather rotin Florida strawberries. Subsequent to the methylbromide application, mefenoxam is applied early tocontrol this fungus and fosetyl-Al and potassiumphosphite are used later in the season because thosetwo materials can be sprayed on the foliage.

Other strawberry diseases are intermittent orincidentally controlled by applications intended tocontrol target diseases. For strawberry fungicides,there are no additional IPM, PHI, or REI concernswith the currently registered materials. There hasrecently been a meeting held in Cincinnati, Ohio byTERA for captan to determine if its carcinogenicpotential can be reclassified based on new EPAguidelines. Thiram and thiophanate-methyl arecurrently undergoing reregistration and the Agencyhas intimated that it would like to mitigate some ofthe perceived risk of thiram. Pyrimethanil is on thethird quarter work plans of EPA’s FY 2004, anddodine still has to go through tolerance reassessment.However, Florida strawberry growers did not reportusing dodine in 2002. Boscalid received a tolerancefor strawberry as of July, 2003.

Weeds

Weed pressure has historically been one of themore difficult management aspects for Floridastrawberry growers for several reasons. First, whenmethyl bromide is employed as the sterilant, thedormant weed seeds such as Carolina geranium andcut-leaf evening primrose are not inactivated. Sinceno treatment is capable of controlling weedemergence the entire strawberry season (six to sevenmonths), these weeds become mid- to late-seasonproblems that impact quality and harvest efficacy.The desired effect of methyl bromide is that it doescontrol the majority of yellow and purple nutsedge,which are considered the worst weeds in this crop.Since the methyl bromide alternatives (except formethyl iodide) don’t control nutsedge, these speciesas well as the aforementioned late season weeds will

be a problem in rows during some or most of theseason.

Another consideration with respect to weeds istheir ability to harbor spider mites. Soon aftertransplants are set, Carolina geranium seedlingsappear. The potential for mite reinfestation is notgreat when the weed grows from transplant holes inthe plastic mulch, because in that position miticideapplications will kill resident mites on both the weedsand strawberry plants. However, this plant also growsin the row ends and field perimeter, and these areasare not treated. Consequently, spider mites canreinfest fields from these plants after miticide residueshave decreased.

Herbicide research for strawberry has also laggedbehind that of pepper and tomato due to the economicsuperiority of these two crops and the fact that someherbicides available to tomato and pepper growers arenot and will not be available to strawberry growers.The most recent report from the USDA’s methylbromide alternatives program (Spring 2003) reviewedonly soil sterilants and one herbicide (Devrinol®) anddid not address weed speciation. Results fromsolarization treatments were similar to those of theuntreated control. Consequently, Florida strawberrygrowers have little experience with new herbicidealternatives.

Herbicide resistance has also been observed inFlorida strawberry production. Goosegrass in the rowmiddles has become resistant to paraquat, due toheavy reliance on this single herbicide. Growers alsoreported potential glyphosate damage to strawberryplants due to transmission from shallow roots presentin treated row middles. In addition to nutsedge andresistant weeds, other problematic weeds includepurslane, pusley, Carloina geramium, cut-leaf eveningprimrose, and eclipta. Dayflower is an emerging weedproblem.

Weed pressure in Florida strawberry productioncomes from two locations, in-bed and the rowmiddles. There are several herbicides which currentlyprovide a degree of control in most cases for rowmiddles. As noted, weeds in the bedded portion of thefield, historically managed by methyl bromideapplication, are now considered the weakest point ofmethyl bromide alternatives. The following points listthe issues with each of the in-bed herbicide options:



February 2004

Napropamide (Devrinol®) appears to havereasonable early season efficacy for most weedspecies. Degradation leads to loss of weed controlmid- to late-season with certain species more tolerantthan others.

Oxyfluorfen (Goal® 2XL) appears to managetroublesome weeds such as Carolina geranium andcut-leaf evening primrose, but the use is throughfallow bed labeling, which requires a 30-day postapplication fallow. This length of time is too longbetween bed formation and transplanting, asmentioned in the nematode section.

Terbacil (Sinbar®) appears promising but thereis a label restriction (110-day PHI) that make thisproduct almost useless for the Florida strawberrygrowing system. Extension specialists are trying towork with the registrant to refine this label withrespect to the extended PHI.

The remaining herbicides available for Floridagrowers are non-selective or grass-killingpostemergence herbicides. One last considerationregarding herbicides (and especially Roundup®products) is the addition of different activeingredients to established trade names. There is a newformulation of Roundup® that offers 24-hour weedcontrol. This is accomplished by the addition ofdiquat to the glyphosate. Growers must be mindfulthat this type of addition has become morecommonplace, and that they must examine the labelto make sure the products they need do not alsocontain an active ingredient not allowed onstrawberry. Other than the aforementioned, there areno IPM or REI concerns with the currently registeredmaterials. Carfentrazone-ethyl, a relatively new non-selective herbicide, is on the third quarter work planof EPA’s FY2004. Sulfentrazone is an A priority onIR-4's 2002 Food Use Workshop list and clopyralid islabeled nationally for strawberry, but is not registeredin the State of Florida.

Birds

Bird predation of strawberries is a sporadic event,but in years in which it occurs, losses can be

substantial. The species primarily associated with thisphenomenon are American robin, cedar waxwing, andcrows. This past season was a good example of birdpredation, wherein it is estimated that robinsconsumed approximately 400,000 flats of strawberries(over $2 million in losses). An extension specialistthat works with vertebrate pests stated that the currenttechnologies (propane cannon at a rate of one per tenacres or robin distress calls) have minimal efficacy,while twisted relective ribbon (silver on one side/redon the other) may be slightly more efficacious.Additionally, audio devices are generally notacceptable since much of the growing area is nowbordered by residential developments. Since thestrawberry is a “naked” fruit, taste repellents such asmethyl anthranilate (grape flavoring) and capsaicin(pepper) cannot be used. The specialist stressed thatthe most important aspect in trying to rid ones field ofbirds is to try and scare them as soon as they startinhabiting the field. Flock presence draws in morebirds.

One interesting potential for taste aversion thatmay well fit nicely into the current pest managementprogram is the application of thiram when a flock firststarts to land in the field. This fungicide is known todiscourage other vertebrate pests from feeding, butnone of the growers were aware of this fact.

Summary

Based on the input of the members of the Floridastrawberry PMSP, the following items have beenplaced on the “To Do” list.

Research

1. Examine efficacy of milbemectin, pyridaben,and etoxazole on pest mites (and thrips formilbemectin) and toxicity to beneficial mites(and beneficial thrips for milbemectin) aswell as phytotoxicity on current and potentialFlorida strawberry cultivars.

2. Examine an alternative mature caterpillarmaterial such as methoxyfenozide.



February 2004

3. Conduct trials to identify cover crops thatwill reduce nematode populations.

4. Conduct herbicide screening trials withflumioxazin, sulfentrazone, andcarfentrazone.

5. Examine the use of thiram as a bird feedingdeterrant.

Education

1. Rededicate effort on providing forwardlooking pest management issues in BerryTimes, the newsletter cited by the growers asone of their historic information sources.

2. Educate growers/scouts with regard towhitefly identification and sanitation,especially on transplants.

3. Educate growers/pest managers with regardto dip applications and resistancemanagement both for strobilurins(azoxystrobin, pyraclostrobin) andneonicotinoids (imidacloprid).

4. Educate growers to the issue that in somecases (e.g. Roundup®) a brand nameassociated with an active ingredient (such asglyphosate) may have something “new” in it(such as diquat) which will influence theoverall performance of the application andmay/may not be used on strawberry.

Regulation

1. Include candidate caterpillar managementactive ingredients in the regulatory queue.

2. Determine if residue data exists that wouldallow a 2-day PHI for malathion anddiazinon.

3. Refine planting window (currently 21 days)for dichloropropene, if possible.

4. Eliminate or greatly reduce the 12-monthplant back restrictrions for Switch®.

5. Greatly reduce the 110-day PHI for Sinbar®.

6. Interact with registrant/state agency to obtainstate registration of clopyralid (Stinger®) instrawberry with existing data.

Strawberry PMSP List of Attendees

Strawberry Growers

! Joel Drawdy

! Aaron Grimes

! Carl Grooms

! Cammy Hinton

! Andrew McDonald

! Johnny St. Martin

! Ronnie Young

Extension Personnel

! Jim Mertely, Gulf Coast Research and EducationCenter at Dover, UF/IFAS, 13138 LewisGallagher Rd., Dover, FL 33527. Tel. (813) 744-6630 ext. 50, [email protected]

! Curtis Nagle, Gulf Coast Research and EducationCenter, UF/IFAS, 5007 60th St. E., Bradenton, FL34203. Tel. (941) 751-7636

! Alicia Whidden, Hillsborough County ExtensionOffice, 5339 S CR 579, Seffner, FL 33584. Tel.(813) 744-5519 ext. 134,[email protected]



February 2004

Association Personnel

! Chip Hinton, Florida Strawberry Growers Assoc.,PO Box 2550, Plant City, FL 33564. Tel. (813)752-6822, [email protected]

! Michael Aerts, Florida Fruit and VegetableAssoc., 800 Trafalgar Ct., Suite 200, Maitland FL32794-8153, Tel. (321) 214-5200,[email protected].

Research Personnel

! Roger Francis, Clemson University,[email protected]

! James Gilreath, Gulf Coast Research andEducation Center, UF/IFAS, 5007 60th St. E.,Bradenton, FL 34203. Tel. (941) 751-7636 ext.237, [email protected]

! Barbra Larson, Department of Entomology andNematology, UF/IFAS, Box 110620, Gainesville,FL 32611. Tel. (352) 392-1901.

! Oscar Liburd, Department of Entomology andNematology, UF/IFAS, Box 110620, Gainesville,FL 32611. Tel. (352) 392-1901 ext. 182,[email protected]

! Joe Noling, Citrus Research and EducationCenter, UF/IFAS, PO Box 111563, Lake Alfred,FL 33850. Tel. (863) 956-1151 ext. 262,[email protected]

! Jim Price, Gulf Coast Research and EducationCenter, UF/IFAS, 5007 60th St. E., Bradenton, FL34203. Tel. (941) 751-7636 ext. 246,[email protected]

! Silvia Rondon, Department of HorticulturalSciences, UF/IFAS, Box 110690, Gainesville, FL32611. Tel. (352) 392-1928.

! Gisette Seferina, Department of Entomology andNematology, UF/IFAS, Box 110620, Gainesville,FL 32611. Tel. (352) 392-1901.

Governmental/Pest ManagementCenters Personnel

! Shani File, UF/IFAS Southern Pest ManagementCenters, PO Box 110710, Gainesville, FL 32611.Tel. (352) 392-4721, [email protected]

! Mark Mossler, UF/IFAS FL Pest ManagementCenter, PO Box 110710, Gainesville, FL 32611.Tel. (352) 392-4721,[email protected]

! Lora Lee Schroeder, EPA Region IV, 61 ForsythSt. SW, Atlanta, GA 30303. Tel. (404) 562-9015,[email protected]

Registrant Personnel

! Jerry Nance, Dow AgroSciences. Tel. (863) 412-4410



Abbreviations:TSM = two-spotted spider miteFT = flower thripsSB = sap beetlesFAW = fall armywormSAW = southern armywormCEW = corn earworm

Abbreviations:TB = tobacco budwormSMC = saltmarsh caterpillar LCB = lesser cornstalk borerSLR = strawberry leafrollerOLT = omnivorous leaftierTPB = tarnished plant bug

Rating scale:E = excellent;G = good; F = fair; P = poor;

Rating scale:? = research needed; … = not used; * = used but not a stand alone

management tool

January 2005

Table 1. Efficacy ratings for pest management tools against invertebrate pests in Florida strawberry.Pests

Pest Management Tools TS

M

Oth

er M

ites

FT SB

Aph

ids

FAW

SA

W

CE

W

TB SM

C

LCB

SLR

OLT

TPB

Whi

tefli

es

Fruj

t flie

s

Mol

e C

ricke

ts

Ant

s

Slu

gs

Registered materialsAbamectin G G F F FAzadirachtin F F F F F F F F G F F G FBacillus thuringiensis G G G G G G GBeauveria bassiana P P P P P P P P P P P P PBifenazate EBifenthrin P F G P F F F F G PCanola oil ...Carbaryl P FChlorpyrifos ...Cinnamaldehyde ...Diazinon P G F G GDicofol P GDisulfoton P FEndosulfan G F F F F F FFenbutatin-oxide GFenpropathrin P F G F F F F F G G F





M

Oth

er M

ites

FT SB

Aph

ids

FAW

SA

W

CE

W

TB SM

C

LCB

SLR

OLT

TPB

Whi

tefli

es

Fruj

t flie

s

Mol

e C

ricke

ts

Ant

s

Slu

gs





management tool

January 2005

Hexythiazox EMalathion P F G F F F F F P GMetaldehydeMethomyl F G G G G G G GMethoxychlor ...Naled P F FNeem oil ...Paraffinic oil ...Insecticidal soap ...Propargite ...Pyrethrins + rotenone P F GPyrethrins + piperonyl butoxide F F F P P P P G G G P E P PSpinosad G G G G E ESulfur





M

Oth

er M

ites

FT SB

Aph

ids

FAW

SA

W

CE

W

TB SM

C

LCB

SLR

OLT

TPB

Whi

tefli

es

Fruj

t flie

s

Mol

e C

ricke

ts

Ant

s

Slu

gs





management tool

January 2005

New Chemistries - IR4(P current IR-4 project)P Acequinocly/TM 413 EP Etoxazole EP Fenpyroximate EP Imidacloprid P E E MethyxofenozideP Milbemectin G ? ? G FP Pyridaben E G EP Pyriproxyfen E F EP Thiamethoxam G E





M

Oth

er M

ites

FT SB

Aph

ids

FAW

SA

W

CE

W

TB SM

C

LCB

SLR

OLT

TPB

Whi

tefli

es

Fruj

t flie

s

Mol

e C

ricke

ts

Ant

s

Slu

gs





management tool

January 2005

Cultural/Non-chemicalCertified pest-free plants EF EG FCrop rotation F F FRemoving ripe fruit from field GResistant varieties EFSanitation G G G G G GTrapsWeed control G GBiological controlsBeneficial mites E P PDamsel bugs P P P P P P P PBig-eyed bugs P PGround beetles P P P P P P PLacewings P P P P P P P P PLadybird beetles F F





M

Oth

er M

ites

FT SB

Aph

ids

FAW

SA

W

CE

W

TB SM

C

LCB

SLR

OLT

TPB

Whi

tefli

es

Fruj

t flie

s

Mol

e C

ricke

ts

Ant

s

Slu

gs





management tool

January 2005

Minute pirate bugs P P F P P P P P P P PParasitic wasps ? G F F F F F F F GPredatory midges P PPredatory thrips F ?Spiders P P P P P P P P PSyrphid fly larvae P F



Toxicity scale:S = slightly toxicM = moderately toxicH = highly toxic

Toxicity scale:O = nontoxic? = no data available

January 2005

Table 2. Toxicity of pest management tools to beneficials in Florida strawberry.Beneficial Insects/

Mites

Pest ManagementTools B

enef

icia

l mite

s

Big

-eye

d bu

gs

Dam

sel b

ugs

Gro

und

beet

les

Hon

eybe

es

Lace

win

gs

Lady

bird

bee

tles

Min

ute

pira

te

Par

asiti

c w

asps

Pre

dato

ry m

idge

s

Pre

dato

ry th

rips

Spi

ders

Syr

phid

fly

larv

ae

Registered materialsAbamectin MH MH MH MHAzadirachtin S S S SBacillus thuringiensis S S S SBeauveria bassiana S S S SBifenazate S S S SBifenthrin H H H H HCanola oil S S S SCarbaryl S H H HChlorpyrifos H H H HCinnamaldehyde ? ? ? ?Diazinon M H ? H HDicofol H SM ? M HDisulfoton H H H HEndosulfan H H H MFenbutatin-oxide S S S S




Mites


enef

icia

l mite

s

Big

-eye

d bu

gs

Dam

sel b

ugs

Gro

und

beet

les

Hon

eybe

es

Lace

win

gs

Lady

bird

bee

tles

Min

ute

pira

te

Par

asiti

c w

asps

Pre

dato

ry m

idge

s

Pre

dato

ry th

rips

Spi

ders

Syr

phid

fly

larv

ae



January 2005

Fenpropathrin H H H HHexythiazox S S S SMalathion M H H HMetaldehydeMethomyl H H H HMethoxychlorNaled H H ? ?Neem oilParaffinic oil M S S SInsecticidal soap H H ? MPropargite MH S ? SPyrethrins + rotenonePyrethrins + piperonyl butoxide MH SM ? MHSpinosad MH MH ? MHSulfur SM S S S




Mites


enef

icia

l mite

s

Big

-eye

d bu

gs

Dam

sel b

ugs

Gro

und

beet

les

Hon

eybe

es

Lace

win

gs

Lady

bird

bee

tles

Min

ute

pira

te

Par

asiti

c w

asps

Pre

dato

ry m

idge

s

Pre

dato

ry th

rips

Spi

ders

Syr

phid

fly

larv

ae



January 2005

New Chemistries - IR4(P current IR-4 project)P Acequinocly/TM 413P EtoxazoleP Fenpyroximate H S ? HP Imidacloprid MH M ? H MethyxofenozideP Milbemectin MH MH MH MHP Pyridaben M S ? ?P Pyriproxyfen S S H SP Thiamethoxam ? ? ? ?



January 2005

Table 3. Indications for disease management products used on Florida strawberriesDisease

Management Product

Angularleaf spot

Anthracnosea

crown rotAnthracnosea

fruit rotAnthracnosea

root rotbBotrytisfruit rot

Phytophthoradiseases

Powderymildew

Misc.leaf spots

Azoxystrobin X X S X Captan X X X XCopper compounds X XCyprodinil + fludioxonil X X Fenhexamid X Fosetyl-aluminum XHydrogen peroxide X X X X XIprodione X Mefenoxam X Myclobutanil X XPotassium bicarbonate X X X XPotassium phosphite X Pyraclostrobin X S X XPyraclostrobin + boscalid X X X XSulfur X Thiophanate methyl X X X XThiram X Triflumizole X

aAnthracnose diseases are caused by Colletotrichum species: C. fragariae and C. gloeosporioides (crown rot), C. acutatum (fruit rot, root rot) bAnthracnose root rot is suppressed by dipping bare root runner plants in solutions or suspensions of the indicated products just before planting X = labeled or used for control of indicated disease S = for suppression only of indicated disease


strawberry pest management strategic plan (pmsp

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