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Reduced-Risk Pest Control Factsheet

CCCCCalifornia vineyards are facing the combination of

an old threat and a new vector—Pierce’s disease, axylem-clogging bacterial disease which was firstidentified over 100 years ago, now has a new andefficient vector, the glassy-winged sharpshooter(GWSS) Homalodisca coagulata. Pierce’s disease isincurable and will generally kill a vine within twoyears of infection. It has a very wide host range (over170 hosts), and it’s feared that it may already bepresent in most areas of California, representing apotential time bomb that may explode with theappearance of an efficient vector, such as the GWSS. A native of the southeast U.S. and first found inVentura County in 1990, the GWSS is a strong flier,able to travel distances of a quarter mile or more.

Kaolin particle film barrier as it appears on blueberry.Adequate coverage of all leaf and fruit surfaces is crucial.

Homalodisca coagulata. Its transparent wings givethe glassy-winged sharpshooter its common name.

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Other vectors of Pierce’s disease include the blue-green, smoke tree, green, and red-headed sharp-shooters. Compared to the GWSS, the blue-greensharpshooter is a poor flier and a much less efficientdisease vector. Because of its voracious feedingbehavior and high mobility, management of the

Other crop diseases caused by the Pierce’s diseasebacterium (Xylella fastidiosa) include: almond leafscorch, phoney peach disease, alfalfa dwarf, oleanderleaf scorch and citrus variegated chlorosis.

GWSS will depend on the integration of severaltactics, including biological control, vegetationmanagement, monitoring, and other strategies.

What is kaolinWhat is kaolinWhat is kaolinWhat is kaolinWhat is kaolinand how does it work?and how does it work?and how does it work?and how does it work?and how does it work?

A relatively new technology, kaolin sprays arecurrently available under the tradename SurroundÒWP Crop Protectant. Please note that Surround is, atthis point in time, the only kaolin product suitableand registered for horticultural use. The kaolin inSurround is processed to a specific particle sizerange, and combined with a sticker-spreader. Non-processed kaolin clay may be phytotoxic. We haveheard of one apple grower who bought a traincarload of “generic” kaolin clay, and killed most of hisapple trees! Surround presents a unique form of pest control:a non-toxic particle film that places a barrierbetween the pest and its host plant. The activeingredient is kaolin clay, an edible mineral longused as an anti-caking agent in processed foods, andin such products as toothpaste and Kaopectate.There appears to be no mammalian toxicity or anydanger to the environment posed by the use of kaolinin pest control.

Inadequate coverage on pear leaves.

The glassy-winged sharpshooter is shownnext to the smaller blue-green sharpshooter.

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Wiped leaf...excellent coverage.

Surround is sprayed on as a liquid, whichevaporates, leaving a protective powdery film on thesurfaces of leaves, stems, and fruit. Conventionalspray equipment can be used, and full coverage isimportant. The film works to deter insects in severalways. Tiny particles of the clay attach to the insectswhen they contact the plant, agitating and repellingthem. Even if particles don’t attach to their bodies,the insects may find the coated plant or fruitunsuitable for feeding and egg-laying. In addition,the highly reflective white coating makes the plantless recognizable as a host.

Surround has proved to be a very effectivemanagement tool for most species of leafhoppers,including the sharpshooters. Results from researchconducted in California on GWSS control in lemonare very promising. In grapes, the combined effect of“disguising” vines and interfering with feeding andprobing behavior should make transmission of thePierce’s disease bacterium less likely on Surround-treated surfaces, but this needs to be confirmed byongoing research in California. The particle spray was developed by Drs. MichaelGlenn and Gary Puterka of the USDA/ARS atKearneysville, WV, in cooperation with the

Modes of ActionModes of ActionModes of ActionModes of ActionModes of Action

Repellency• White color visually repels some insects, or acts to

disguise the plant• Unfamiliar touch cues• Difficulty gripping surface

Irritation• Particles stick to insect parts• Confusion and excessive grooming• Obstacle to feeding and egg-laying

Engelhard Corporation, which began marketing theproduct in 1999 on a limited basis, after severalyears of trials with grower-collaborators. Surround isnow available across the U.S., and is listed by theOrganic Materials Review Institute (OMRI) for usein organic production. Although at first glance the film may appear toblock light, Surround actually increases net photo-synthesis, and can provide secondary benefits to theplants’ overall health. Surround keeps the plantscool so that photosynthesis can continue longer intothe afternoon on hot days, after untreated plantshave already shut down because of heat stress.Grapes treated with Surround show improved vigorand studies have shown positive effects on juiceflavor.

Spraying rSpraying rSpraying rSpraying rSpraying recommendationsecommendationsecommendationsecommendationsecommendations

• Thorough coverage is key for protection.• Sprays before expected infestation are much more

effective.• Normal air-blast and hand-held sprayers (but not

backpack sprayers) are preferred.• Re-apply to cover new growth and after heavy

rains.• Re-sprays most important on young fruit.• WWWWWine grapesine grapesine grapesine grapesine grapes sprayed up to veraison will have

minimal adherence to berries. Applications afterveraison will adhere better to grape berries.Applications may be made up to two weeks beforeharvest, then continued post harvest. If you areuncertain about Surround residues on grapes, it isrecommended to spray only up to veraison.

• TTTTTable and raisin grapesable and raisin grapesable and raisin grapesable and raisin grapesable and raisin grapes—A supplemental labelenables applications up to 5 mm berry size; thensprays may be continued post harvest. Applicationsare not recommended between 5 mm and harvest inorder to avoid unsightly residues on harvested fruit.

• For targeted control of glassy-winged sharp-glassy-winged sharp-glassy-winged sharp-glassy-winged sharp-glassy-winged sharp-shootershootershootershootershooter: apply during the dormant period up to 5mm berry size to prevent sharpshooter movementinto vines.

Parasitized egg masses are tan to brown in color withsmall, circular holes at one end of the eggs.

Glassy-winged sharpshooters lay eggs on the under-sides of leaves, usually in groups of 10 to 12. The eggmasses appear as small, greenish blisters. These blistersare more easily observed after the eggs hatch, when theyappear as tan to brown scars on the leaves.

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Surround has proved effective in suppressing thefollowing grape pests:several types of leafhoppers, including glassy-winged, redheaded, and bluegreen sharpshooters,and grape leafhopper; leafrollers, Japanesebeetles, thrips, grape leaf skeletonizer, and Junebeetle.

A Systems ApprA Systems ApprA Systems ApprA Systems ApprA Systems Approachoachoachoachoach

Surround will be most effective when used within awell-managed agro-ecological system combining themost appropriate cultural and chemical methods for thespecific vineyard situation, pest complex, and localclimate. Such a system will integrate soil building,habitat for beneficial organisms, and well-tuned nutrientand water management. Soil building and nutrient/water management are twosides of the same coin and could be considered preven-tative pest management. A healthy soil high in organicmatter will have better water and nutrient holdingcapacity. Plants receiving too much or too little of eitherwater or nutrients, particularly nitrogen, are moreattractive and more susceptible to damage by insectsand diseases. Good water management, through water-stress monitoring, conserves valuable (and expensive)soil nutrients, reduces contaminated runoff, and con-serves water. Providing habitat for beneficial organisms is likehiring millions of helpers whose sole aim in life is to eatpests. Nitrogen-fixing cover crops can do double duty ashabitat for beneficial organisms if managed correctly.

Recommended ARecommended ARecommended ARecommended ARecommended ATTRA Publications:TTRA Publications:TTRA Publications:TTRA Publications:TTRA Publications:

� Farmscaping to Enhance Biological Control� Overview of Cover Crops and Green Manures� Farm-Scale Composting Resource List� Sustainable Soil Management� Sustainable Management of Soilborne

PlantDiseases� Drought Resistant Soils

All available free of charge. Call 800-346-9140or visit our website at http://www.attra.ncat.org

Further Resources

Several researchers are examining different facetsof GWSS management. Many of them may becontacted through information listed at:http://www.ucr.edu/news/gwss/

Following is contact inforFollowing is contact inforFollowing is contact inforFollowing is contact inforFollowing is contact information for a few of themation for a few of themation for a few of themation for a few of themation for a few of therrrrresearesearesearesearesearchers working on GWSS and Pierchers working on GWSS and Pierchers working on GWSS and Pierchers working on GWSS and Pierchers working on GWSS and Pierce’ce’ce’ce’ce’sssssdisease.disease.disease.disease.disease.

Gary Puterka, 304-725-3451,GPuterka@afrs.ars.usda.gov

Gary has researched kaolin clay particlefilm barriers for control of leafhoppers on pears andis a member of the Kern County GWSS Task Force.

Beth Grafton-Cardwell at (559) 646-6591,bethgc@uckac.edu.

Beth is researching tactics for managingGWSS in citrus in the context of slowing movementfrom citrus into grapes. The GWSS is not considereda pest of citrus.

Matthew Blua, (909) 787-6301,matthew.blua@ucr.edu.

Matthew is also researching tactics toprevent or slow movement of GWSS into vineyards.He has found that 95% of GWSS fly at 5 meters orlower. He is investigating effects of physicalbarriers combined with pesticide treatments on thetransmission of Pierce’s disease to vineyards.

Surround WP manufacturer:EngelharEngelharEngelharEngelharEngelhard Corporationd Corporationd Corporationd Corporationd Corporation101 Wood AvenueP.O. Box 770Iselin, NJ 08830-0770Phone: (732) 205-5000Toll-free: (877) 240-0421Fax: (732) 321-1598

Alexander Purcell at (510) 642-7285,purcell@nature.berkeley.edu.

Alexander is looking at vegetation managementas a strategy for managing the blue-green sharpshooter, theprimary vector of Pierce’s disease along coastal areas. Thisstrategy revolves around removing the five or six plantspecies in any given riparian habitat that the sharpshooteris attracted to during its egg-laying period. This strategycan potentially increase biodiversity and reduce the need forinsecticide use.

Bruce Kirkpatrick at (530) 752-2831,bckirkpatrick@ucdavis.edu.

Bruce is knowledgable about host range of Pierce’sdisease, as well as diseases and symptoms caused by thebacterium in other hosts.

Mark Hoddle, (909) 787-4714mark.hoddle@ucr.edu orDave Morgan, (909) 787-4360,dmorgan@citrus.ucr.edu

The wasp Gonatocerus triguttatus is successfullyreducing populations of the sharpshooter in Mexico andTexas. The wasp parasitizes the sharpshooter by laying itseggs inside those of the larger insect. Once hatched, thewasps eat their way out.

PierPierPierPierPierce’ce’ce’ce’ce’s Diseases Diseases Diseases Diseases Disease is a concise and authoritativehandbook on the disease, its spread, and strategiesfor containing it. The publication is written by UCscientists on the forefront of the battle. The 20-pagepublication, produced by the UC Division of Agricul-ture and Natural Resources (ANR Publication21600), is priced at $6 a copy, plus tax and shipping,with discounts available for purchases of 10 or more.PierPierPierPierPierce’ce’ce’ce’ce’s Diseases Diseases Diseases Diseases Disease is available at local UC CooperativeExtension offices, directly from ANR CommunicationServices (6701 San Pablo Avenue, 2nd Floor, Oak-land, CA 94608-1239), or by phone (800-994-8849),fax (510-643-5470), and online athttp://anrcatalog.ucdavis.edu.

Glassy-winged Sharpshooter images source: “Glassy-Winged Sharpshooter Online Media Kit,” University of CaliforniaDivision of Agriculture and Natural Resources, Communication Services website,

http://danr.ucop.edu/news/MediaKit/photos/default.shtml. Copyright 1999 by the Regents of the University ofCalifornia. Reprinted with permission. Other images courtesy of Engelhard, Inc.

The ATTRA Project is operated by the National Center for Appropriate Technology under a grant from theRural Business—Cooperative Service, U.S. Department of Agriculture. These organizations do notrecommend or endorse products, companies, or individuals. ATTRA is located in the Ozark Mountains atthe University of Arkansas in Fayetteville at P.O. Box 3657, Fayetteville, AR 72702. ATTRA staff membersprefer to receive requests for information about sustainable agriculture via the toll-free number 800-346-9140.