Parks, T. H.

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?\o. 226 BULLE1I'l OF THE Ac.RICLLTUR\L Exn."10"< SER\ ICE, TnE Orno S1 u c U-..1\ Li'.<!TY }A>.U.\RY, 19-13 The Japanese Beetle Fig. r.-Distribution of the Japanese beetle. The shaded area indicates the area oi general or continuous infestation; the dots indicate places at which isolated colonies have been found or where bc~tles have been taken in traps. By T. H. PARKS Extension Entomologist, The Ohio State University THE OHIO STATE UNIVERSITY AND THE u. s. DEPARTMENT OF AGRICULTURE, COOPERATING AGRICULTURAL EXTENSION SERVICE, H. c. RAMSOWER, Director, Columbus Printed and distributed in furtherance of the Acts of May 8 and June 30, I9I4 The Japanese Beetle [he. J.:tp,U1eSC bee.tie ,\u .. iJL11t ill\ U1troc!ULC.d 111tO thi& UJLll1tJ \ 110111J,1p111, has bewme .:t Ve!\ ,mnovmg me! cle~truLtiH. pest In J,1p m, it J& oi mmor import.ince, bemg held ll1 Lhc.d,. b\ b10logILJl mflueme& It ",1s fir~t tound rn this wuntrv ,1t Rn erton, :t\ J, m 1916 t:.mc.e th.it time, it has g1JduJlly sprt,1d It \\a' first tound m Oh10 m Hgr, "hen .:t tew 'pec1mem ot the bLetle '" e1 e c.:tptmed 111 b.:t1t tr,1ps It is no\\ firmly e&t.:tblished m thee \'tern h.:tlt ot Ohio Dunng the II \e,u& tolkmmg the hr&t ,1ppt.:t1Jme ot the J.:tp,mesc beetle m om St.:tte it h.:ts not cause.cl ,my twnom1c <lam,1ge to tood crop' Howe\ er, m J few locat10ns it lus bmlt up su111uent popul lt!on so that its cl im.:tgc h.:ts been noted on ornament.,!&, a fe\\ sh.:tde trLC' ,m<l rn one mst,mLc, ,1 wnsiderable ,1rer. ot turi m ,1 golt cour'e In se\ enl ot the \tLtnt1c Co i 't 'tatLs, .:tnd 111 e.:t~tern Pennsvh .ima, the msect h.:ts g1eath d.im.iged m,111y tnut md shade tl ccs, flowers, shrubs, me! s\\ tet wrn, an<l the. l uv Jt, or g1 ubs, h n e been a m,qor pest of turt In .idd1t10n to dnect chm.:tge by beetles and grnbs, qu,1r.:tntme and mspect10n requirc.ment& h,n e restncted the tree movement ot nursery and fl01 m !>tod,., inn ts, vel.i<.t .ible,, s01l, ma nm e, .:tnd compost These i tqmreme11ts h n e resulted 111 mcreased e'<pense and 111conve111ence to nurservmen 111 wmpl)mg \\Ith qvar.:tntme regul.1t10ns In a latge 1re,1111 ~ew Je1sq "he1e the pLst h,1s bec.n p1esent longest, tlie beetle popul.1t10n, ,1her ,1 pLno<l oi ') to 10 vears of st.nous 111fe,t'lt10n, h ts cl10pped marh.edlv to a pomt where dawage lrom Japane~e beetle is not ncarlv so SL\ ere a' fo1merly This i~ believed to be due to the pie&ence ot b10log1c.:tl p.u ,1,Jte,, both ,i.1mul 111<l b llter 111 "l11d1 dt.st10\ the hn .:tt l n the. n L \\ ei are,1s of 111festat10n 111 southern Ne\\ J erse), 1far) bnd, DeLm are, e,1stern PtnnsylvJmd, Jnd e,1~tern Yirg1111a, the d.:tmage is frequently se>ere Weather co11d1t10ns ::ipparentl) pb) a cons1der,1ble part Jt1 deteimmmg the degree ot 111tu.tJt1on 111 m' p.1rt1cvl u ~e 1~011 If we may 1udgt from the m1ury that has occurred m the e,1stern states, due to the acuvitv of both the beetles and grubs, we must consider this 111sect potentially, and ±or a time .it least, one of the most destmctn e pests th,1t h,1s 111vaded Oh10 DESCRIPTION OF THE BEETLE \'-D L\R\ \ The adult Japanese beetle 1s easily recogmzed It is about 12 mch long and ~ mch wide It has J shmy green head and thoiai.,., while the wmg covers are coppery brown On the sides and up of the abdomen are small white dots (see colored 1llmtr.iuon, pJge 5). The larval, or grub, stage mhabits the sml and resembles our white grub, familiarly h.nown as the young of the May beetle But, the Japanese beetle larva attams only about half the size of most of our species of native white grubs When full grown, the larva changes to a pupa m the soil, and then transforms mto a beetle 111 June and July MAN"'ER OF SPRE.\D A"N"D DEVELOP'\1ENT IN OHIO Up to the end of i941, the beetle populat10n m Oh10 had reached damagmg numbeis at only four pomts, namely, a sizable area m each of the cities of "Pop1llza 1aponzca Nc\\m Cle\ cl md .md 1 oung~tm\ n, .md small are.1~ m \\ estein LaI .. e ,:mcl northern Guernsey counties Durmg the season of 1942, th1ee additional locaht1es were wund m \\ hich the msect had multiplied greatly The~e are w1thm the cities ot Denmson, Dover, and l\.h.ron How the msect got mto Oh10 is a matter of speculation, but undoubtedly IL " 1s aided through channels of commerce, smce the beetles can fly only a short d1st.ince and are not earned far by the wmd They can be tr.insported long dist.rnces by railroad trams, automobiles, and truch.s, while the grubs can be <..1rned th1ough shipments of balled nUtsery stocl-. and m the soil ot potted pbnts Federal quarantme agencies have attempted to prevent long distance spread of the msect through regulation of shipment of frmts and nursery stoch., and to some e\.tent through the movement of vehicles on highways However, quarantmes have been unable to solve the problem presented by merchandise and by passenger earners Results ot beetle trapping in Oh10 indicate that much, if not most, of our 111festat10n is traceable to railways brmging the adult beetles from the heavy area of infestat10n m the e.:tst and droppmg them in citie~, where trams are made up, and where freight is unloaded The pomts where the most beetles have been caught in traps, and the three heaviest centers ot mfestation now found m Ohm occur m cities having railroads leadmg directly from infested areas m the east Besides the areas of mfestat10n referred to, the beetles have now been taken m tiaps at many widely separated pomts m the eastern half of our State. This trappmg reveals a rapid bmld-up of the beetle populat10n at Cleveland, Youngstown, North Salem, Dennison, Dover, and Akron On the other hand, trappmgs made at Toledo, Columbus, East Liverpool, and Canton, where some beetles were caught seven or more years ago, have not shown any marh.ed increase m abundance of the 111sect and no damage has resulted. The trappmgs made 111 1942 revealed several new pomts of mfestat1on, prmcip.illy on the east side of the state, where local citizens had not suspected the presence of the beetle Very few specimens have been collected m the western half of Oh10 H.\BITS The adult Japanese beetles feed on more than 250 h.mds of plants. When abundant, they devour the green silks of corn, damage unsprayed foliage and frmts of early vanetles of apples and peaches, frmt and foliage of red raspberries. Thev sh.eletomze the leaves of grape, cherries, some shrubs and shade trees, and devom or deform openmg buds and flowers of roses, leaves and flowers of cannas, z111mas, and about one dozen other ornamental flowers and shrubs. The e\.tent to which m1ury may develop is shown 111 Figs. 2 and 3. The beetles appear about the middle of June and reach their maximum numbers throughout the month of July, or early August. After the middle of August they gradually dimmish m numbers until they disappear late 111 September, 01 October. The beetles feed on bnght sunny days, when they can be seen clustered on flower buds, foliage, and npenmg frmts of favorite host plants Durmg July, August, and early September, the females lay their spherical, pearly-white eggs in the soil beneath turf into which they burrow. They deposit from one to four eggs, arranged singly, and again emerge to resume feed-ing. The eggs are laid over a period of 35 to 40 days, until 30 to 60 eggs have been bid by each female. During this period the insects frequently collect in bunches, or "ball-up" on the turf, or on the plants where feeding. During rainy or cloudy weather, and during the cooler parts of the day, the beetles are inactive, but during periods of warm sun-shine they Ry to nearby trees and shrubs .and feed voraciously. Fig. 2.-Rcsults of beetle fccding--showing the typical skclctonizing of the leaf. The eggs hatch in 2 to 3 weeks and the grubs begin feeding immediately, being found within the upper 2 inches of the soil. They grow rapidly until cool weather arrives, when they go 2 to 12 inches into the soil to pass the winter. In April they reappear near the surface of the soil to resume feeding. Although the larvae occur most abundantly in turf, they may be found in smaller numbers feeding on the roots of nursery stock, shrubs, or Rowers. Their damage to turf is frequently severe, and badly injured sod has most of the roots severed and can be turned back with the hands (see Fig. 4). The larvae are found from late July until June of the following year, after which time they pupate and the beetles emerge from mid-June to early in August. There is only one generation annually. HosT PLANTS The following economic plants are attacked by the beetles: PLANTS FREQUENTLY INJURED: Faod Crops Grape Cherry Plum Apple* Peach* Raspberry Blackberry Com (ears) ~Principally to early maturing fruits. Tree.f and Ornamenta/j· American elm Horsechestnut Buckeye Linden Willow European white birch Lombardy poplar + Rose Althea Ornamental cherry Hollyhock Cann a Virginia creeper Marshmallow Primrose Stages of the Japanese Beetle Fig. 3 -Japanese beetles feeding on the fruit and leaves of apple (about one-half natural size) . Below ground the adult is represented laying eggs. The other drawings represent eggs, a newly hatched grub, several stages of the growing grub, and the pupa or resting stage (all about twice natural size). The framed insert shows the adult beetle, about twice natural size. (Color plates by courtesy of tl1e Extension Service of the University of Maryland, from a color drawing furnished them by the U.S. Department of Agrirnlture). PL\' r' Beim '-.\ c unore '-.p rt.·1 So\IHI\Jr> Fro lTPO'- I\ s p lr •\.!; lJ<, '\.on\ n m 1pk Pr!\ et Rhulnrb Pm 011- 7mm1 \.Ii i\f I H rn thorne D ihli i Clo\ er f'!O\\ enn~ qumct. \~tcr <;;o\ be m H1b1sCL s (,erdnrum TrumpLt \me lvfornmg glon The plants not ment10ntd r:uel), if eve1, are attached senously Iniurv ~eldom occurs to .tpple toli.ige or fruits i ece1; mg the regular spr .iy applications through the se.ison 01 to cheiry foliage until after the crop is harvested Iniuq to corn is c.iused chiefly bv the beetles de\ounng the green s1lh. before pollination has been completed This results 111 imperfect development of h.erneb It occurs most severely to corn planted near susceptible trees, or shrubs \\here the. beetles congregate Very early and also late planted corn are not M.ely to be senously .mach.ed Shiftmg of the corn plantmg date has been practiced successfully to avoid rn3ury 111 the heaviest mfested areas of the east Garden beans are rarely senously damaged, though soybeans may be fed upon ro a considerable e"\.tent Many weeds are severely miured, of which ~m 1rtweed and Indian mallow are favontes Cor-..TROL ME \SURES 1he control of the JJpanese beetle 1s difficult, and commumty effort 1s of much import.mce Protect10n of 111d1v1dual plantmgs 1s attended by some degree of success by employmg one or more of several practices which have been 1 ecommended and used m the east These are (a) spr aymg, (b) covering or 1arnng, ( c) pbntmg p!dns, ( d) soil treatment Sprnvmg-It has been possible under eastern cond1t1ons to protect the foliage of plants bv keepmg them thoroughly covered with a heavy deposit of spray This Vi most successful only where spraymg 1s commenced before the beetles have taken possess10n of the plants, and repeated regularly throughout the penod of beetle flight The followmg sprays are recommended for tnal (I) Hydrated lime 8 pounds 6 heapmg teaspoonfuls OR Water 25 gallons r quart This 1s a non-p01sonous spray and, if kept applied, repels the beetles The white spray residue mah.es the sprayed plants unattractive ( 2) Lead arsenate I~ pounds 4 level tablespoonfuls Wheat fl.our r pound OR 3 level tablespoonfuls ¥.Tater 25 gallons r gallon Powdered sh.1mmilh. may be substituted for the whe1t flour These sprays ( r) and (2) merely repel the beetles, and do not h.111 many of them Arsemcal sprays mav be used on sh1 ubs and shade trees and on non beanng and late varieties of apple trees The spray residue problem mal.es rt undesirable to apply arsemcal sprays to early matunng summer vanet1es of apples, and to cherries 1nd small frmts immediatelv before the crop is harvested Arsemcal sprays are likely to 1111ure the peach twigs and foliage, and for that reason, heavy lime spray (No r) rs recommended for non-beanng peach trees Only earlv vanetles of peach frmts are severely m3ured by the beetles. 6 (3) Rotenone bearing material (powd. derris, or cube). I Yz pounds OR I heaping tablespoonful vVater ............. . ..... 25 gallons I quart This spray is both a killing and a repellent material, and is safe to use on small fruits and peaches where arsenical residue would be objectionable. Owing to the scarcity of rotenone bearing materials during the war period, its use is permitted only on food crops and should not be applied to ornamentals. (4) Pyrethrum spray (used according to manufacturer's directions). This is a contact spray and kills only those beetles struck by the spray. For that reason one must wait until the beetles are present. Pyrethrum does not stain the flowers or foliage and is safe on ripening fruits. Fig. 4.-Expo~ure of Japanese beetle larvae by rolling back an area of dead turf. ( Courtesy U. S. Department of Agriculture, Bureau of Entomology and Plant Quarantine.) Covering. or farring Plants.-\Taluable small plants may be protected from the beetles by covering them with cheesecloth during the period of heavy flight. Likewise, the insects may be shaken, or jarred from the plants in the morning before the beetles are active. They may be collected and destroyed, or shaken directly into a vessel containing water and kerosene. The jarring method requires daily attention and care to be successful. Planting Plans.- In the case of market sweet corn, arrangement of planting dates, so that silking is avoided during the heaviest beetle flight, is practiced successfully in the East. If this cannot be done, dusting the tips of the ears liberally with hydrated lime, as soon as the silk appears, will do much to protect the green silk. Planting of non-susceptible trees, shrubs, and flowers should be followed as much as possible in bndscaping property located 111 heavy beetle infested territory. ::iod T; eatment.-This is ,1 verv effecnve method for protecting turf against injurv bv the lJrvae. A. Ltwn m,1~ be protected from J.tp.rnese beetle grubs by tre,1tJ;10 it wnh le,1d ,1rse1ute at the rate of io pounds of the arsenical to each r,ooo s~ uare feet of surface. Each ro pounds of lead arsenate should be mixed with .1 bushel of slightly moist sand, soil, or organic fertilizer and distributed even!~ by h.rnd or with ,1 fertilizer spreader. If preferred, ro pounds of the lead arsen,1te c.m be mixed in 20 gJ!lons of V\later and applied as a coarse spray. Whichever method is used, It should be followed immediately by a "watering in"' process to wash the chemical off the grass and into the soil around the roots. The treatment may be m,1de .1t ,my time of year the ground is not frozen. This will protect the turf for 5 to 8 yeJrs and will also control the native white grub~. e.1rthworms, ,md moles. If ,1 new lawn is being made, it may be grub-proofed by incorporating about 25 to 30 pounds of lead arsenate to each I,ooo square feet of the upper 3 inches of soil. This tre.ltment will not harm birds. Neither will it protect flowers from being injured by beetles originating from neJrby untre,1ted ]J\Yns. Do not apply the b1d arsenate to soil in flower beds, gardens, or around shrubs. Few grubs are found in such locations and some plants cannot tolerate rhi~ much 2rsenic. :\on-lead arsenicals are not recommended for soil treatment. UsE OF JAPANESE BEETLE TM.PS TrJps designed to attract and c.1pture the beetles are now on the market. They are considered beneficial in somewhat reducing the number of beetles, but in themselves do not constitute an effective me;ins of control. Thev are of gre,tte>t value in determining the location of newly established colonies. , Traps have been very hdpful to Federal and State agencies studying the relative number of insects from year to year, and their spread to new territory. If traps are used by private individuals, they should supplement other more effective means of control, particularly the treatment of turf to prevent grub development. NATURAL ENEMIES OF THE INSECT The larval, or grub, stage of the insect is attacked and killed by several natural enemies. Starlings and robins have been observed to dig the grubs from the turf and devour them. Insect parasites and predators, some of which are introduced species, play a small, but as yet ineffective part in reducing grub infestation in turf. In the older infested areas of New Jersey, parasitic nenurodes (microscopic and near-microscopic eelworms) are known to atock the grubs and have received some attention. Still more hopeful is the recent discovery of the presence of a disease of the larvae known as "milky white disease." This is so called because it changes the Japanese beetle larvae to a chalk-white color after it has killed them. The dise,1se is caused by spore-forming bacteria that have been artificially propagated and inoculated into the turf with some degree of success in the East. Once established in the soil, the disease organisms become more prevalent with each succeeding generation of beetles. This disease is now being experimented with in Ohio by the Ohio Agricultural Experiment Station. It remains to be seen how much aid it will give under Ohio conditions. 8 

The Japanese Beetle

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The Japanese Beetle

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