Managing The Japanese Beetle: A Homeowner's Handbook - USDA

United States Department of AgricultureManaging the Japanese Beetle:A Homeowner’s HandbookAnimal and Plant Health Inspection Service

Popillia japonicaThe U.S. Department of Agriculture (USDA) prohibitsdiscrimination in all its programs and activities on the basis ofrace, color, national origin, age, disability, and, whereapplicable, sex, marital status, familial status, parental status,religion, sexual orientation, genetic information, politicalbeliefs, reprisal, or because all or part of an individual’sincome is derived from any public assistance program. (Notall prohibited bases apply to all programs.) Persons withdisabilities who require alternative means for communicationof program information (Braille, large print, audiotape, etc.)should contact USDA’s TARGET Center at (202) 720-2600(voice and TDD). To file a complaint of discrimination, writeto USDA, Director, Office of Civil Rights, 1400 IndependenceAvenue, S.W., Washington, D.C. 20250-9410, or call (800)795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equalopportunity provider and employer.Mention of companies or commercial products does not implyrecommendation or endorsement by USDA over others notmentioned. USDA neither guarantees nor warrants thestandard of any product mentioned. Product names arementioned solely to report factually on available data and toprovide specific information.This publication discusses the use of pesticides. All uses ofpesticides must be registered by appropriate State and/orFederal agencies before they can be recommended.CAUTION: Pesticides can be injurious to humans, domesticanimals, desirable plants, and fish or other wildlife if they arenot handled or applied properly. Use all pesticides selectivelyand carefully. Follow recommended practices for the disposalof surplus pesticides and pesticide containers.APHIS 81-25-003August 2015

Managing the Japanese Beetle:A Homeowner’s HandbookThe Japanese beetle (Popillia japonicaNewman) is a highly destructive plant pest offoreign origin. It was first found in the UnitedStates in a nursery in southern New Jersey in1916. In its native Japan, where the beetle’snatural enemies keep its populations in check,this insect is not a serious plant pest.In the United States, however, the beetle enteredwithout its natural enemies and found a favorableclimate and an abundant food supply. By 1972,beetle infestations had been reported in 22 Stateseast of the Mississippi River and also in Arkansas,Iowa, and Missouri. Since then, the pest hasspread to Southern and Western States, but toughregulations and careful monitoring have preventedits establishment there. Without its natural checksand balances, the Japanese beetle has become aserious plant pest and a threat to Americanagriculture.This map shows the distribution of Japanese beetles in theUnited States as of January 2015.1

The Japanese beetle adult—an attractive pestA typical cluster of Japanesebeetle eggsBoth as adults and as grubs (the larval stage),Japanese beetles are destructive plant pests. Adultsfeed on the foliage and fruits of several hundredspecies of fruit trees, ornamental trees, shrubs,vines, and field and vegetable crops. Adults leavebehind skeletonized leaves and large, irregular holesin leaves. The grubs develop in the soil, feeding onthe roots of various plants and grasses and oftendestroying turf in lawns, parks, golf courses, andpastures.Today, the Japanese beetle is the most widespreadturf-grass pest in the United States. Efforts to controlthe larval and adult stages are estimated to cost morethan 460 million a year. Losses attributable to thelarval stage alone have been estimated at 234 millionper year— 78 million for control costs and an additional 156 million for replacement of damaged turf.How to Recognize the JapaneseBeetle’s Life StagesThe adult Japanese beetle is a little less than half aninch long and has a shiny, metallic-green body withbronze-colored outer wings. The beetle has six smalltufts of white hair along the sides and back of its bodyunder the edges of its wings. The males usually are2

Japanese beetle larvaJapanese beetle pupaslightly smaller than the females. You are most likely tosee the adults from late spring through midsummer.During the feeding period, females intermittently leaveplants, burrow about 3 inches into the ground—usuallyinto turf—and lay a few eggs. This cycle is repeateduntil the female lays 40 to 60 eggs.By midsummer, the eggs hatch, and the young grubsbegin to feed. Each grub is about an inch long whenfully grown and lies in a curled position. In late autumn,the grubs burrow 4 to 8 inches into the soil and remaininactive all winter. This insect spends about 10 monthsof the year in the ground in the larval stage.In early spring, the grubs return to the turf and continueto feed on roots until late spring, when they change intopupae. In about 2 weeks, the pupae become adultbeetles and emerge from the ground. This life cycletakes a year.Homeowner ControlNo quick fixes can rid homeowners of the Japanesebeetle once it becomes established. However,scientists with USDA’s Agricultural Research Serviceand Animal and Plant Health Inspection Service(APHIS) have developed an integrated pestmanagement (IPM) program for homeowners based3

JANFEBMARAPRILMAYJUNEJULYAUGSEPTOCTNOVDECThe Japanese beetle life cycle (Illustration by APHIS employee Joel Floyd)on field experiences. The program combinesbiological, cultural, and chemical strategies. It will beeffective if homeowners are willing to monitor bothadult and larval beetle populations closely andimplement this program with neighbors and their localagricultural or horticultural organizations.4

What is IPM?The IPM concept comes from the realization that anydisruption of a pest population will affect not onlytargeted pests but beneficial organisms in theecosystem as well. Decisionmakers who chooseIPM are attempting to manage pests, not toeradicate them, while at the same time exertingminimal impact on the environment.IPM uses biological, cultural, mechanical, andchemical controls to keep pest populations belowlevels that cause economic damage. And, becausetolerance to the presence of insect pests varies amongindividuals, the choice of methods will reflect themanagement objectives and control philosophy of theuser. Components of an IPM program for any pest includesurvey, problem delineation and selection ofcontrol methods, application of controls, andevaluation of their success.Why Follow an IPM Program?Homeowners should consider the following reasonsfor implementing an IPM program:Automatically and routinely applying pesticides canbe counterproductive, economically wasteful, andenvironmentally unsound.The Japanese beetle is here to stay. Therefore, wemust learn to “live with” or manage this insect pestwhile attempting to minimize its impacts.It is not necessary to eliminate the beetle in orderto protect your trees, plants, and lawn.It is hard to predict when and where Japanesebeetle populations will increase, and there is noguaranteed control formula to follow. Consequently,intermittent monitoring and appropriate planningare necessary for adequate management.5

Survey MethodsIn order to plan and implement appropriate controlstrategies for the Japanese beetle, you must firstsurvey your property for both grubs and adult beetles.Traps for adult beetles operate primarily with twochemical lures. A combination of a pheromone, orsex attractant, and a floral lure attract both male andfemale adult beetles to the trap. Then, as a result oftheir clumsy flying and the design of the trap, theyend up caught in either the bag or funnel portion ofthe trap.Japanese beetle traps can be used to assess thebeetle population in a given area. For instance, ifyou put a trap out while the adults are flying and findthat beetles fill the trap in 1 day, you probably have aJapanese beetle problem. If, during a week, the bottomof the trap is barely filled, you probably do not need tobe concerned. Adult beetles can fly long distances, sothose caught in your yard may have come from severalhundred yards away. For this reason, it is difficult toestimate the number of grubs in your turf from adulttrap catches.To survey for grubs, you need to calculate the numberof Japanese beetle grubs per square foot in your lawn.This estimate is important for deciding the severityof your white-grub problem and whether treatment isnecessary.Japanese beetle grubs can be sampled in late summer(August to October) and late spring (April to June).Timing will vary by geographic location.If your lawn has brown or dead areas during thenormal growing season, survey near the edge of thedamage. If you find that grubs are the cause of thedamage, clearly this area should be treated.Otherwise, take several randomly selected samplesthroughout the lawn. The density of Japanese beetlegrubs often varies widely within a small area. Bytaking several samples, you may be able to pinpointthe damage and therefore selectively treat specificareas rather than the whole lawn.6

Using a shovel, dig a square hole 8 by 8 by 3 inchesdeep in the turf. Turn the sod over on some newspaperand search the grass roots and the soil in the hole forgrubs. Turn the turf back into the hole and add water tohelp the grass recover. Record the number of grubsfound in the sample location so you can map out oraverage grub densities. To convert these numbers tothe number of grubs per square foot, multiply them by2.25. Generally, you should consider treating areas inyour lawn with more than 10 grubs per square foot.Control MethodsTo control the Japanese beetle, several potentialtactics are available. The choice of method willreflect the management objectives and controlphilosophy of the homeowner.Chemical ControlsHomeowners who decide to use chemicalmethods in an IPM approach to Japanesebeetle management should base their decisionon several factors. Choosing what pesticide toapply and when to apply it comes down to avalue judgment for the individual. First, youmust assess the risks and benefits of pesticideuse. Correct timing and application are probablythe most essential elements for success withpesticide applications. Because pesticides aretoxic materials, users must read and follow labeldirections exactly. When used improperly,insecticides can pose serious hazards to peopleand wildlife. There is also increasing concernabout the fate of insecticides in the environmentand the potential of pesticide runoff to causewater contamination.7

HeterorhabditisbacteriophoraEach State has its own agricultural chemicals handbook,updated yearly for appropriate control recommendations.The following chemicals are effective for use in the controlof the Japanese beetle adult and its grubs:Chemicals for methrinChemicals for Larvae: Imidacloprid (Merit insecticide for turf; Marathon for nursery use)HalofenzideTrichlorfonChlorantraniliprole (for professional applicators)These lists do not include all materials registered forJapanese beetle control. For further details regardingchemical controls, consult your local CooperativeExtension Service. Before using any of thesechemicals, check the label for particular formulationsregistered for Japanese beetles, read the entire label,and carefully follow instructions regarding applicationmethods and recommended rates.Biological ControlsHomeowners who choose biological methods tocontrol Japanese beetle populations can successfullyuse parasites, nematodes, fungi, or other biologicallybased approaches. Some of these agents arecommercially available to homeowners; others arenot. While they take a little longer to produce thesame results as insecticides, biological control agentslast longer in the environment. More importantly, theydo not adversely affect nontarget or potentiallybeneficial organisms.8