use of these practices. As a result, the gapbetween ‘conventional’ and ‘organic’management has narrowed.

Successful management of many grape pests ispossible using organic control methods, such asthose approved by NOFA- NY or othercertification organizations. In this talk I will firstdescribe the key components common tosuccessful IPM programs- whether conventionalor organic. I will then explain what types ofspray materials are available to organic growers.Finally, I will outline organic managementoptions available for the two major grape pests-Grape berry moth and Eastern grape leafhopper,and briefly touch on how other pest populationsmay be affected by current organic practices.

Components of IPM. Organic and IPMapproaches to pest management are approachesthat rely on knowledge and informed decisionmaking. The key components of the IPMapproach are:

1. Pest Identification. Proper identification ofinsect pests and an understanding of theirbiology is essential for successful management.Many insects feed in vineyards, but only a fewcause economic damage. Some cause veryconspicuous feeding injury but have no effect onvine productivity. Grape Plume Moth larvae, forexample, emerge early in the spring and webtogether leaves. The result- althoughconspicuous- has no economic effect, becausethis pest completes its development anddisappears by mid-June. Yet, many growersmistakenly apply treatment, most often after thelarvae have completed their development. Other

Organic grape growers are faced with the samecomplex of insect pests as are conventionalgrape growers. Growers of both organic andconventional grapes will likely be faced with theneed to manage grape berry moth and grapeleafhopper, the two major pests that are widelydistributed and common throughout grapegrowing areas in the Northeast. In addition tothese two key pests, growers in specific areasmay face other common pests such as caneborers (common in vineyards surrounding Keukalake), Japanese beetles (somewhat common inthe Lake Erie region), European red mite (LongIsland) or rose chafer (vineyards with sandysoils). Other pests, such as flea beetles,cutworms, tumid gall makers, and graperootworm, may only appear sporadically.The difference in conventional and organicmanagement methods for insect pests largelyrests on what actions a grower is willing to take(or materials he is willing to apply) whenconfronted with an economically-important pestproblem. Ten to 15 years ago, the gap between‘conventional’ practices and ‘organic’ practiceswas enormous. Pest managementrecommendations at that time called for 3applications of insecticides to all vineyard blockson a preventative basis - a “one size fits all”recommendation. More recently, however, this‘preventative’ approach has been supplanted bythe Integrated Pest Management (IPM)approach. IPM practices -including RiskAssessment, vineyard sampling for pests, andeconomic injury levels - have been developedand adopted by many grape growers. Theaverage number of insecticide applicationsmade in New York vineyards has been reducedfrom three down to one per vineyard through the

MANAGEMENT OF INSECT PESTS IN ORGANIC VINEYARDS

Tim MartinsonDepartment of Entomology

NYS Agricultural Experiment Station, Geneva, N.Y.Cornell University

Pages 45-48 in: Organic Grape and Wine Production Symposium, 1995, ed. R. Pool, 102 pp.

less conspicuous pests, like grape rootworm,may cause more serious injury. Properidentification of the pest is an essential first stepto appropriate management.

2. Monitoring Pest Populations. Economiceffects of insect infestations depend onpopulation levels of pests. Especially invineyards, pest populations vary greatly fromyear to year and vineyard to vineyard.Monitoring vineyards to determine populationlevels is the key to avoiding unnecessary sprayapplications - and for timely application of spraymaterials when necessary to prevent economicdamage.

3. Economic thresholds. The economicthreshold is defined as the population or injurylevel (determined by monitoring) at which atreatment should be applied to prevent economiclosses due to the pest. Our research program hasdeveloped economic thresholds for grape berrymoth and grape leafhopper that provide guidancefor making treatment decisions.

4. Risk assessment. Risk assessment meansusing information about the vineyard site,weather conditions, and crop condition (such ascropping level and vigor) to forecast or predictthe likelihood that pest populations will causeeconomic injury. Through research, we havedeveloped risk assessment criteria for grapeberry moth and leafhoppers that are usefulguides to management, as I will mention later inthis presentation.

These four elements are common to bothconventional IPM and organic managementprograms. Using them is the key to taking fulladvantage of the natural factors (biological andnon-biological) that often keep insectpopulations well below the economic threshold.

Organic Spray Materials. Where organic andconventional IPM programs differ is in the typesof spray materials that can be used. Organicgrowers use only non-synthetic, naturally

derived materials. These materials, by theirnature, are less toxic, more selective, and lesspersistent than conventional pesticides. They areoften more costly to apply. Using these controlmethods requires more careful attention toresults, and sometimes more applications toachieve the desired results.

Organic materials fall into many differentcategories. Some of the major ones are:

1. Botanicals are insecticides extracted orderived from plants. Many are very toxic toinsects. These include rotenone, pyrethrum,ryania, sabadilla, and neem. Note that someplant-derived materials (such as nicotine) are notconsidered acceptable under organic certificationstandards.

2. Oils and Soaps. These materials controlinsects through physical effects on respiration,feeding, or by disrupting the insect cuticle.Included in this category are mineral oils,vegetable oils, dormant oils, and insecticidalsoap.

3. Biologicals. Materials derived frompathogenic organisms, such as nematodes,bacteria (Bacillus thurengiensis), fungal andviral pathogens are in this class.

4. Behavioral Control agents Materials thatprotect crops by modifying insect behavior -suchas repellents, antifeedants, attractants or sexpheromones used in mating disruption - but donot kill insects are in this category.

Growers that wish to be certified by an organiccertification organization such as NOFA-NYneed to carefully study guidelines to determinewhat specific materials are allowed. Somebotanical insecticides, for example, containingredients such as petroleum distillates, sprayadjuvants, or synergists (such as piperonylbutoxide, commonly used with pyrethrum), thatare prohibited. Many surfactants, spreader-stickers, and other spray adjuvants are alsoprohibited.

Organic Management for Grapes. Over thepast several years, we have extensivelymonitored insect pests in vineyards that havereceived no insecticide treatments. Our studieshave consistently shown that economicallysignificant pest infestations failed to develop inwell over 50% of vineyards surveyed.Moreover, high insect populations tend to occurat the same small proportion of vineyard sitesyear after year. What this means is that insectpressure is not a major impediment to organicproduction for many growers. Organicalternatives are available for the two major pestsof grapes- grape berry moth and eastern grapeleafhopper.

Grape Berry Moth. Research has shown thatgrape berry moth infestations tend to recur in thesame sites year after year. By followingguidelines in the publication Risk Assessment forGrape Berry Moth and Guidelines forManagement of Eastern Grape Leafhopper,growers can classify each vineyard block as‘high-risk’ or ‘low-risk’. Many ‘low-risk’ areaswill not develop economic infestations of berrymoth in most years. For high-risk areas, twoalternatives are available. Pheromone matingdisruption using ISOMATE-GBM® is a controlmethod that is non-toxic and highly specific togrape berry moth. Pheromone dispensers areplaced on the top wire of the vineyard in earlyMay. The pheromones then diffuse out of thedispensers over a period of 10- 14 weeks,disrupting the chemical signals used by malemoths to locate and mate with females. Thisprevents oviposition and subsequent larvaldamage. Use of this material is described fullyin the bulletin Pheromonal control of the grapeberry moth: an effective alternative toconventional insecticides. Bacillus thurengiensisis a biological insecticide that is effective incontrolling larval berry moth. Applications ofthis material require careful timing, becauselarvae need to ingest it before burrowing into thegrape cluster and feeding internally. Twoapplications during the extended egg-layingperiod of each generation are required, becausethis material persists for < 3 days in the field.

Grape Leafhopper. Grape leafhopper is a pestthat can affect vineyard productivity, but thatoften fails to develop high populations. Ourstudies have shown that vines can toleratemoderate populations of leafhoppers, withoutaffecting productivity. In addition, highleafhopper populations tend to occur in a smallproportion of vineyards. This is because optimalweather conditions for population growth occuronly in warmer than average years, and an eggparasite, Anagrus epos, is often effective inpreventing population growth. However, wehave noted that in some organically-managedvineyards, high populations of leafhoppers candevelop over a period of a few years, and mayrequire treatment. Organic vineyards withrecurring problems may require a differentapproach than conventional vineyards. Inorganic vineyards, application of organicmaterials around bloom may be necessary toreduce populations and allow biological controlby Anagrus epos to prevent population growthlater in the season. In trials, insecticidal soap hassometimes been effective in reducing leafhopperpopulations. However, this material, to beeffective, must be applied with adequatecoverage (high water volume), and only remainsactive until it dries. Thus it is most effectivewhen applied around dawn or dusk. Repeatapplications are probably necessary. Somebotanicals, such as rotenone, and pyrethrum/rotenone mixtures have also been effective ininsecticide trials.

Other Insect Pests. Many other insect pestsappear sporadically in vineyards, or occur at asmall proportion of vineyard sites. Specificinformation about these pests can be found in aseries of fact sheets available through CornellCooperative Extension. Efficacy of organicallyacceptable materials for controlling these pests isunknown, and organic growers may have todevise, through trial and error, their ownmethods for dealing with these pests.

In closing, I want to briefly mention results fromour ongoing SARE project that terminated in

1994. Over five years, and in three differentvarieties, Concord, Elvira, and Seyval, we hadeconomically-important infestations of grapeleafhopper only in one year of the project, andfailed to have economic infestations of grapeberry moth, in part through the use of matingdisruption. A longer-term problem, however,began to emerge. Starting in the fourth year ofthe project, significant infestations of grape

rootworm began to appear in the Concord block.While adults of this root-feeding species areeasily controlled with conventional insecticides,no organic methods are available. In futureyears, as growers adopt both conventional andorganic IPM tactics, this pest may again emergeas a major concern for grape growers. Furtherstudies are needed to assess alternate controlmethods for this pest.

References

Dennehy, T.J., L.G. Clark, and J.S. Kamas. 1991. Pheromonal control of the grape berry moth: aneffective alternative to conventional insecticides. New York’s Food and Life Sciences Bull#135.

Martinson, T.E., C.J. Hoffman, T.J. Dennehy, J.S. Kamas, and T. Weigle. 1991. Risk assessment ofgrape berry moth and guidelines for management of the eastern grape leafhopper. NewYork’s Food and Life Sci. Bull. #138. 10 pp.

Grape IPM Fact Sheets. (Series of six, available through Cornell Cooperative Extension).