~!tB" t;~..;:. Stored-Grain .oq-= .... Insects n "'. ~ ~ "9 ft,. II .. - "-,7 -,- ::-_~ v ~ • " C :" , .~ ~ ~ ¥- ~ , • J < '"" ABSTRACT
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Kg Scm ....-..... ____.. .. 0. < _~ .. . .,.,....-- CONTENTS Page Int rod uction ...... 1 Grain weevils 000000000000000000000000000000000000 1 Granary weevil 00000000000000000000000000000000 1 Rice weevil 0 0 0 000 0 0 0 0 0 000 0 0 0 0 00 000000000000 000 2 Maize weevil 0 0 00 0 0 0 0 0 000 00000000000 00 0 0 0 0 0 0 000 3 Broadnosed grain weevil 00 0 0 0 0 0 0 0 00 0 0 0 0 0 0 00 0 0 000 3 Coffee bean weevil 0 0 0 00 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 00 0 4 G rain borers 000000000000000000000000000000000000 6 Lesser grain borer 0 00 00 0 0 0 0 0 0 0 0 0 00 0 0 00 0 0 00 0 0 0 0 0 6 Larger grain borer 0 0 0 0 0 0 0 0 00 000000000000 00 0 0 00 0 8 Grain moths 000000000000000000000000000000000000 9 Angoumois grain moth 0 0 0 0 0 00 0 0 0 0 0 00 0 00 0 000 0 000 9 Pink scavenger caterpillar 00000 000 0000 00000000000 10 European grain moth 0 00 00 00000000000 00 0 0 0 0 0 0 00 0 12 Rice moth 000000000000000000000000000000000000 12 Flour moths 000000000000000000000000000000000000 14 Indian meal moth 0 0 0 0 00 00000000000000 00 0 00 0 0 000 14 Mediterranean flour moth 0000000000000000000000 15 Meal moth 000000000000000000000000000000000000 16 Grain and flour beetles 000000000000000000000000000 19 Cadelle 000000000000000000000000000000000000000 19 Sawtoothed grain beetle 00000000000000000000000 0' 20 Merchant grain beetle 00000000000000000000000000 21 Squarenecked grain beetle 0 000 00 0 000 0 0 000 000 0 0 0 0 21 Foreign grain beetle 0000000000000000000000000000 22 Mexican grain beetle 000000000000000000000000000 22 Siamese grain beetle 0000000000000000000000000000 22 Flat grain beetle 00000 00000000000000000000000000 23 Rusty grain beetle 00000000000000000000000000000 24 Confused flour beetle 000000000000000000000000000 24 Red flour beetle 0 00 0 0 000 0 0 0 0 0 0 0 0 0 000 0 0 0 0 0 0 0 0 00 0 26 American black flour beetle 0 0 0 0 0 0 0 0 0 0 • 0 0 0 0 0 0 0 0 0 0 27 Longheaded flour beetle 000000000000000000000000 28 Slenderhorned flour beetle 0000000000000000000 000 29 Smalleyed flour beetle 00000000000000000000000000 29 Depressed flour beetle 00000000000000000000000000 29 Broadhorned flour beetle 0 0 0 0 0 0 :- 0000000000000000 29 Larger black flour beetle 000000000000000000000000 30 ,..- .... ' • < • 'oO '""t' •. , .« Page Eggs of flour and grain insects · · · · · · · · · · · · · · · · · · · .. 31 Mealworms 32 Yellow mealworm · · · · · · · · · · · · · · · · · · · · · · · · · · . · .. 32 Dark mealworm 34 Lesser mealworm 34 Black fungus beetle 34 Redhorned grain beetle 35 Dermestid beetles 37 Black carpet beetle · · · · · · · · · · · · · · · · · · · · · · · · .. 37 Trogoderma beetles 37 Spider beetles 40 Hairy spider beetle · · · · · · · · · · · · · · · · · · · · · · · · .. 40 Whitemarked spider beetle 40 Brown spider beetle 41 Other spider beetles 41 Miscellaneous beetles · · · · · . · · . · · · · · · · · · · · · · · · · · · .. 42 Twobanded fungus beetle 42 Hairy fungus beetle 42 Corn sap beetle .. ·····.······················ .. 43 Cigarette beetle .. ···.························ .. 44 Drugstore beetle · · · · · · · · · · · · · · · · · · · · · · · · · · · · · .. 45 Catorama beetles 45 Murmidius beetle 46 Booklice or psocids 46 Silverfish 47 Cockroaches 48 Flour or grain mites. · · · " 50 Parasites of grain pests 52 How grain becomes infested. ················.·.. .. 55 How to prevent or reduce primary infestation 56 Prepared by the Aarlcultara. Relearch Service Ualted Stat. Departmeat 01 Aarlcultare This handbook supersedes and enlarges Farmers' Bulletin 1260, "Stored Grain Pests." IssuedFebuary 1978 Washington, D.C. Revised and approved fex' printing January 1986 STORED-GRAIN INSECTS INTRODUCTION Since the establishment of Federal be found in grain may be called standards for grain under the pro simply beetles, moths, and meal visions of the Grain Standards Act, worms. Their presence usually does Federal grain supervisors and feder not indicate a condition likely to ally licensed grain inspectors have affect the grain trade, if the grain, been required to identify the various after it has reached the elevator, is species of "live weevils and other screened and fanned to remove these insects injurious to stored grain" insects. which may be present in the grain. This handbook briefly describes For accurate identification, uniform the biology, life histories, and habits names should be used by all inter of stored-grain insects and gives ested persons, including shipper, pur effective methods for the prevention chaser, and elevator operator. and control of grain infestations. Of the five primary insect pests, Grain weevils, grain borers, grain the granary weevil, the rice weevil, moths, flour moths, grain and flour the maize weevil, and the lesser grain beetles, mealworms, dermestid bee borer may well be called grain wee tles, spider beetles, miscellaneous bee vils. The fifth primary pest, the tles, booklice or psocids, silverfish, Angoumois grain moth, so destruc cockroaches, flour or grain mites, tive to wheat and corn, may be called and parasites of grain pests are dis a grain moth. Other insects likely to cussed. GRAIN WEEVILS Of the five true weevils that attack snouts, as shown in figures 1, 3, and grain in the United States, only three 4. are of primary importance-the Granary Weevil granary weevil, the rice weevil, and the maize weevil. Except locally, the The granary weevil, Sitophilus broadnosed grain weevil and the granarius (Linnaeus),' is a small, coffee bean weevil are of minor moderately polished, blackish or importance. All but the coffee bean weevil have elongated beaks or I Coleoptera, Curculionidae. 2 AGRICULTURF. llANDROOK NO. ~ O O, U.S. DF.PT, O~' lIGHICULTL'lIE ch. ~ ".", l ._ {;" " . ft>il. ILf" to "",,, ;1ad"": ' ''''''.'>« ...", ad ult. " "'. moon il ad ult STORED GRAIN INSECTS 3 about three thirty-seconds of an inch slightly larger,up to one-eighth of an in length. It varies from reddish inch long, and darker than the rice brown to nearly black and is usually weevil adult, the degree of variation marked on the back with four light within each species makes them diffi reddish or yellowish spots (fig. 1B). cult to tell apart (fig. 1C). The thorax The rice weevil closely resembles the of the maize weevil is densely and granary weevil in form but differs in uniformly pitted with round punc color and markings, and it has fully tures. developed wings beneath the wing It is a common pest of a variety of covers. The thorax is densely pitted grain crops and causes tremendous with somewhat irregularly shaped losses to corn in the South, reducing punctures, except for a smooth, the kernels to dry powder and hulls narrow strip extending down the (fig. 2). The adults fly from the middle of the upper (dorsal) side. granaries to the fields, where they This weevil has been known since start infestations that may continue early times. It is found in all parts of after harvest and may be especially the world where grain is used and is destructive in storage. one of the worst pests in stored grain. The life history and early life This insect is particularly abundant in stages are similar to those of the rice warm countries, where it breeds con weevil (fig. 3). The rate of devel tinuously and rapidly destroys all opment is slightly slower; a minimum unprotected grain. of 30 days is required for passing The adult rice weevils live, on an through the egg, larval, and pupal average, 4 to 5 months, and each stages. female lays 300 to 400 eggs during this period. The early life stages are almost identical in habit and appear Broadnosed Grain Weevil ance to those of the granary weevil. The broadnosed grain weevil, During hot weather, the egg, larval, Caulophilus oryzae (Gyllenhal),' is a and pupal stages may be passed in as small, dark-brown snout beetle few as 26 days. This period, of slightly less than one-eighth of an course, is greatly prolonged during inch long. In form and color, it cool or cold weather. resembles the granary weevil some what but differs from it and other grain-infesting weevils by having a Maize Weevil shorter, broader snout (fig. 4C). The weevil is occasionally found in The maize weevil, Sitophilus Georgia and South Carolina and is zeamaise Motschulsky, for a long widespread in Florida, where it is a time referred to as the larger strain or serious pest of stored grains, but it is race of the rice weevil, is now recog not found in northern grains. It is nized as a distinct species. Although unable to breed in dry, hard, unin- " AGRI CULT URE HANDBOOK NO. 500, U.S. DEPT. OF AGRICULTURE jured grai n, but it docs a ttack soft or damaged grain or gra in th at has been attacked by other grai n insects. It is a st ro ng fl ie r. a nd . li ke the mai ze we ev il. flies to t he c o rnfields a nd infests the grain before it beco mes , fully ha rdened. The adult weevils normally live a bout 5 m o nths. and . during thi s t im e. ea c h female lays 200 to 300 small white eggs. usu ally in broken portions of the gra in. In a few day s. the eggs hatch. and the small. white. legless grubs feed on the softer por tions of the grain until fully gro wn (fig. 4A ). They the n transform into white pupae (fig. 48) and. in a few days. transfo rm into adult weevils which cu t their way ou t of the grain. In summer. the period from egg to adu lt is about I month. Coffee Bean Weevil The coffee bean weevil, Araecerus [ascicu latus ( De Gce rj .s is a very ac tiv e. robust. dark- b ro wn beetle two-sixteen th s to three-sixt eenths of an inch long. It is covered with a mottled light- and dark-brown pubes cence. This insect may be easily ree ognized from figure 5. T his weevil is found in many countries and is extremely abundant in the S o ut hern S tates. where it breed s in dried fru it. co ffee berries. cornstalks. com, and the seed and s ee d p od s o f an al mos t endless R\-J05Q variety of p lants. The co ffee bean Figure 2.-An ear of co rn badly damaged by weevil is a strong flier and is fre maize " 1:1: \;15. The car was hit against a quently seen in the co rn fields of th e table to jar loose a dry powdery substance. or farinaceous material. to reveal the great amount of damage done. 'Coleopte ra. Ar uhn hidac. !rl'OREO G RAIN INs rr'TS , A B c .~ . - ~ f ,..,.., ( ..- ~ " .... f'_' • • _ ••• _ _, _•. 011 .. _ ...... 6 AGRI CULT URE HANDBOO K NO. 500, U.S. DEPT. OF AGRICULTURE South on exposed and damaged ears. It lays eggs in the soft kernels of corn and continues to breed after the corn has been harvested a nd placed in sto rage. This insect does not cause much dam age to co rn in storage. since the corn becomes too hard to be attractive. It may. however. be very abunda nt locally in corn in Florida during the first 3 months of storage. This weevil reported ly caus ed total destruction of a sack of kafir seeds in Hon olulu . Over th e country, th e coffee bean weevil is a minor grain pest. W' -517" Figure 5.- Coffee bean weevil adult. about three-sixteenths of an inch long. GRAIN BORERS Three species of grain borers arc during World War I. It is widespread esta blished in the United Sta tes. The in the Gulf States, and grai n samples lesser grain borer is widespread in the infested with this beetle arc found in grain centers of this country and is a all la rge gra in cente rs. The lesser serious pest of stored grain . The grain borer is readily distinguished large r grain borer and the bamb oo from other grai n pests by its slender powderpost beetle are confined to the cylindrica l form and small size. It is Southern States and are not of com polished dark brown or black. with a mercial importance. somewhat roughened surface. and is about one-eighth of art inch long and Lesser Grain Borer one thirty-second of an inch wide (fig. 6A). The larval and pupal stages The le ss e r g rain b o r e r. are illustrated in figure 7. This grain Rhyzopertha dominica (Fabricius).' borer belongs to a family of beetles is one of the smallest beetles of those that has the head tu rned down under injurious to grain in this country. It is the thora x and tha t is armed with known to many grain dealers as the powerful jaws used for cutting into Australian wheat weevil because of wo od . O r iginally nat ive t o t he the large supplies of infested wheat Tropics. the lesser grai n borer has that were imported from Australia spread through commerce to all part s 'Coleoptera. Bost richidae. of the world. 6 AGRI CULT URE HANDBOO K NO. 500, U.S. DEPT. OF AGRICULTURE South on exposed and damaged ears. It lays eggs in the soft kernels of corn and continues to breed after the corn has been harvested a nd placed in sto rage. This insect does not cause much dam age to co rn in storage. since the corn becomes too hard to be attractive. It may. however. be very abunda nt locally in corn in Florida during the first 3 months of storage. This weevil reported ly caus ed total destruction of a sack of kafir seeds in Hon olulu . Over th e country, th e coffee bean weevil is a minor grain pest. W' -517" Figure 5.- Coffee bean weevil adult. about three-sixteenths of an inch long. GRAIN BORERS Three species of grain borers arc during World War I. It is widespread esta blished in the United Sta tes. The in the Gulf States, and grai n samples lesser grain borer is widespread in the infested with this beetle arc found in grain centers of this country and is a all la rge gra in cente rs. The lesser serious pest of stored grain . The grain borer is readily distinguished large r grain borer and the bamb oo from other grai n pests by its slender powderpost beetle are confined to the cylindrica l form and small size. It is Southern States and are not of com polished dark brown or black. with a mercial importance. somewhat roughened surface. and is about one-eighth of art inch long and Lesser Grain Borer one thirty-second of an inch wide (fig. 6A). The larval and pupal stages The le ss e r g rain b o r e r. are illustrated in figure 7. This grain Rhyzopertha dominica (Fabricius).' borer belongs to a family of beetles is one of the smallest beetles of those that has the head tu rned down under injurious to grain in this country. It is the thora x and tha t is armed with known to many grain dealers as the powerful jaws used for cutting into Australian wheat weevil because of wo od . O r iginally nat ive t o t he the large supplies of infested wheat Tropics. the lesser grai n borer has that were imported from Australia spread through commerce to all part s 'Coleoptera. Bost richidae. of the world. sroneu GItAIN INHA-'TS 7 A hI"" ~ (i, •• I00.... ,,,,. _ ,.• • "'-' .... k...... ,_ ""_,...._ _ ...... "_ 1 l ...... IAI. . _ 8 AGRICULTURE HANDBOOK NO. 500, U.S. DEPT. OF AGR ICULTURE Both the beetles an d larvae cause Larger Grain Borer serious damage in warm climates by attacking a grea t variety of gra ins. Th e larger grai n borer, Pros Figure 8 sho ws how dest ructive they t ep han us {r u nco /us ( H o r n ). ! is a can be to wheat kernels. which. in small. da rk -b ro wn, elongate th is case , were literally riddlcd by thc cylindri cal beetle abo ut one-sixth of boring of the adults a nd their larvae. an inch long. It is very similar in Th e damaged kernels a re always sur appeara nce to the lesser grain borer, rounded by powder from the chewed but may be d istinguished fro m tha t up grain. insect by its larger size and compara Each female lays 300 to 500 eggs tively smooth, polished surface (fig. and deposits them, singly or in clus 9A). ters, upon the loose grain.The eggs T his tropi cal insect has limited di s hatch in a few days, and the small tribution in this country. It is occa wh it ish g ru bs. o r la rv a e . cra wl siona lly foun d infesting corn in the actively abo ut the grain, and feed on Sou th and has been reported from the flour produced by th e bori ng bee Tex as, Californ ia. and th e District of tles or bore directly into gra ins tha t Colum bia. Simi lar to the lesser grain have been slightly damaged . Th ey bo rer in hab its, it belongs to a family complete th eir growth wit h in the of beetles that is main ly des truc tive to grain, transform into white pupae. timber. Like the lesser grain borer. it and, in time. change into adult bee ha s p ro ba bl y acquired the gra in lies. which cut their way out of the feeding habi t rather recently. grain. In summer, the period from An other member of the fam ily, the egg to adult is abo ut I mon th . bamboo powderpost beetle, Dinod- H:"-JOti J figure S.- Whenl kernels thoroughly riddled and devoured hy bo ring and feeding of lesser grain bo rer and its larva. STORED GRAIN INSECTS 9 I D c A B ON-30M Figure 9.-Larger grain borer: A, adult; B, larva; C, pupa; D, antenna of adult. erus minutus (Fabricius);' occa from Louisiana and Florida. In gen sionally infests stored grain in the eral appearance, it resembles the United States. It has been reported larger grain borer (fig. 6B). GRAIN MOTHS The term "grain moth" includes This is the moth most commonly only those moths capable of found in infested grain in this destroying sound, unbroken grain country, and it is not likely to be con kernels. They are not as abundant as fused with any other grain moth. It the flour moths, which are principally attacks all cereal grains, is found in pests in broken, damaged kernels or all parts of the world, and is particu milled products. larly injurious in the South, where it attacks grain both in the field and in Angoumols Grain Moth storage. In the North, it survives the winter mainly in the larval form in The Angoumois grain moth, Sito kernels of grain in storage or in scat troga cerealella (Olivier)," is a small tered wheat in litter, straw piles, and buff or yellowish-brown moth with a baled straw. The emerging moth flies wing expanse of about one-half inch. to the wheatfields in May and deposits eggs upon the developing "Lepidoptera. Gelechiidae. grain. 10 AGRI CULT URE HANDBOOK NO. 500, U.S. DEPT . OF AGRI CULTURE Under normal co nditions. each Widespread use of the co mbine female lays an average of 40 eggs; ha rvester ha s reduced wheat dam age alt ho ugh, under favorable co nditions. by th is moth to a minimum. How individual moths have been known to ever, in the southern portion of the lay as ma ny as 389 eggs. T he eggs. co mmerci a l corn-growing area, it which a re white when first laid . soon pe riodica lly causes heavy losses to cha nge to a reddish colo r. They are stored co rn . Figur e 10 sho ws an ear laid on wheat heads, on the exp osed of corn with the extern al evidence of tips of co rn ea rs in the field. or on a hea vy a tt ack by the Angoumois sto red grain . grain mo th. Figure I I sho ws the suc Upon hat ching, eac h larva cra wls cessive stages in the develo pment of to a kernel of grain a nd often spins a thi s insect in a kernel of wheat . from sma ll entrance cocoon to assist it in egg to adult. Figure 12A sho ws the bo ring into the hard kernel. Afte r ad ult mot h. enteri ng the grain. it feeds on either the endosperm or the germ until fully Pink Scavenger grown. It then eats out a cha nnel to Caterpillar the outside of the seed and makes a weakly fastene d flap at the exit by The pink scavenger caterpillar. cutting the shell one-half 10 th ree Sathrobrota riley; (Walsingharnj.' is fourt hs of the ci rcumference of a the larva. or caterpillar. of a small circle. Th e larva then spins a silken mo th. It is pink, wit h a pale-brown co coon a nd c ha nges to a redd ish head a nd tho ra cic shield . and is b rown p upa. La ter. as a moth, it abo ut five-sixteent hs of an inch long pushes its way thr ou gh the flap , The whe n fu lly gro wn (fi g. 12C). The period fro m egg to adult may be moth which develop s from tbis larva completed in 5 weeks. although development is usua lly slower. ' Lcpidopteru. Cosmoptcng iduc. B ~ - J 066 Figure 1O .-Ear of corn showing heavy infestation by the A ngoumois grain moth. Note that cer tain kernels have three emergence holes. and that many kernels have served as food for two lar vae . STO RED GRAIN INSEC,'TS 11 Female moth lays egg on grain kemal. The larva emerging from egg gnaws a hole, no larger than a pin prick, through which it enters the kernel. Kernel cut showing entrance channel. Larva feeds and grows. enlarging cavit y. The tull-grown larva is as long as kernel in which it has eaten out a large cavi ty . The pupa is the stage between larva and adult moth . ANGOUMOIS GRAIN MOTH The moth leaves DEVELOPMENT IN WHEAT kernel by round hole shown . 8:'oi -3067 f-i gur e l Lc-- Life cycle of the Angoumois grain mot h on '"heat. 12 AGRICULTURE HA~IJIlOOK NO , MO, U.S . ner-r. O F ACKlcULTURE ~" J" " 11. - (;,"" motn.· 14'. ~ , .,, " m... J"" .."n. d " ~ . ' '''''', p" , ""''"'.'' co",,,,"" . d"lo; ' ....' , p'" ""'" . ... i••malle, Ihan lh, An~oum o; , ~,aln mal u,il)' in th, f..ld or ...h;le in Ihc moth. wilh a wing e' panse of ,lighlly c,ih on SOUl n,m fa m" I.., lhan half on inch (f, ~ . 1281. 1 ho fo,ewi ng, .,~ handed and mon ied European Grain Moth wilh ydlow. lodd..h bro" n, and Tho Europoan ~ ra ; n mOlh . .-\'rm1ora ~. , Inf..lal;On bc~ in. in Ih. Angou mni, ~I.io mOlh. It ,nfe,'- all field and con, inu", ali., Ih. expanse of a bout half an inch and is pale grayish brown or law ny (fig. 15). The larva somewhat resembles that of th e Ind ian meal moth . When fully grown. the larva is a bo ut half a n inch long and varies in color from whit e to " :\ -3071 Figure D .- Cut ea r of co rn showing charac re ri snc feed ing a nd destructi on by pink scavenger cater pilla r larva e. La rvae eat fro m one kern el to another an d often sever ker nels fro m cob. Larva e so met imes eat into 8~ - .'ONl co b and transform into pupae there. Pupae Figure l-t. c- European grain moth adult . Adu lt a rc a bo ut one-third as long as the kernel" has a wing expa nse of a bo ut one-ha lf of an shown. inc h. o .0 - ,I :! .... 'C'''. Rs ·)On Figu re IS.- Rice moth adu lt: teft, dorsal view with wings spread ; right, side view with wings folded to body. Ad ull has a wing spread of about one-half of an inch. 14 AGHl CUl.T URE HANDBOOK NO. 500, U.S. DEPT. OF AGH ICU LTU RE a dirty, slightly bluish gray with occa grown. When feeding upon grains, sional tints of green (fig. 16). they spin dense silken tub es and web Damage by this pest, as with all the grain kern els into the walls of the moth pests, is done by the larvae, tubes. Th e moth s live I to 2 weeks, which a re rather ge ne ral feeders. and each female lays 100 to 200 eggs. They attack such materials as rice, I n summe r, the develop ment period cocoa, chocolate, dried fruit , biscuits, from egg to adu lt is abo ut 6 weeks. and seeds. The larvae produce a Th e rice mo th has not as yet become dense webbing as they become fully very widely sprea d in th is country. B~ · J 0 7J Figure 16. l-ull-gro .... n la rva of the rice moth. about one- half of an inch long. FLOUR MOTHS Am ong the 1I0ur moth s are some lished in whole grai n and other seeds of the co mmo nest and most serious and cause injury. especia lly by eating pests of gra in produ cts. They are des out the germ. ignated as flour moths. not because t hey feed entire ly u pon fl ou r or Indian Meal Moth milled product s, b ut becau se they seldom attack sound kernels. These T he Ind ian meal mot h. Plodia insects prefer broken grains, grains interpunctella (Hub ner),' is a rather injured by maj or grain pests. and handsome moth with a wing expanse more especially milled cereal prod of nea rl y three-fourths of an inch ucts such as 1I0ur. break fast foods. (figs. 17 and ISA). It is easily dis and meals. All thr ee 1I0ur moths are tingui shed from other grain pests by commonly found in grain ware the peculiar markings of its fore hou ses, but the Indian meal moth wings, which are redd ish bro wn with and the meal moth are pro bably the a co pper lu ster on the outer tw o most frequently reported. Thes e two thi rds but whitish gray on the inner moths may, un der exceptionally or body ends. favora ble co nditions, become estab- Each female moth lays 100 to 300 14 AGHl CUl.T URE HANDBOOK NO. 500, U.S. DEPT. OF AGH ICU LTU RE a dirty, slightly bluish gray with occa grown. When feeding upon grains, sional tints of green (fig. 16). they spin dense silken tub es and web Damage by this pest, as with all the grain kern els into the walls of the moth pests, is done by the larvae, tubes. Th e moth s live I to 2 weeks, which a re rather ge ne ral feeders. and each female lays 100 to 200 eggs. They attack such materials as rice, I n summe r, the develop ment period cocoa, chocolate, dried fruit , biscuits, from egg to adu lt is abo ut 6 weeks. and seeds. The larvae produce a Th e rice mo th has not as yet become dense webbing as they become fully very widely sprea d in th is country. B~ · J 0 7J Figure 16. l-ull-gro .... n la rva of the rice moth. about one- half of an inch long. FLOUR MOTHS Am ong the 1I0ur moth s are some lished in whole grai n and other seeds of the co mmo nest and most serious and cause injury. especia lly by eating pests of gra in produ cts. They are des out the germ. ignated as flour moths. not because t hey feed entire ly u pon fl ou r or Indian Meal Moth milled product s, b ut becau se they seldom attack sound kernels. These T he Ind ian meal mot h. Plodia insects prefer broken grains, grains interpunctella (Hub ner),' is a rather injured by maj or grain pests. and handsome moth with a wing expanse more especially milled cereal prod of nea rl y three-fourths of an inch ucts such as 1I0ur. break fast foods. (figs. 17 and ISA). It is easily dis and meals. All thr ee 1I0ur moths are tingui shed from other grain pests by commonly found in grain ware the peculiar markings of its fore hou ses, but the Indian meal moth wings, which are redd ish bro wn with and the meal moth are pro bably the a co pper lu ster on the outer tw o most frequently reported. Thes e two thi rds but whitish gray on the inner moths may, un der exceptionally or body ends. favora ble co nditions, become estab- Each female moth lays 100 to 300 HlUIlF.D GIIAIS INllECTS ,nlo • It,hlob,,,,,,n pupa, from ...·hi"d! the adull mOlh d.,.~ln p• • IKI 1. 1., ....., Dun", .. arm . a 'h. f, th. IIKI mal moth lTIlIy pa.. Ihrou,h IM.g.. lanlli. .nd pupal .1&1" io {I 10 ' . ed.. n.e Ill",. of 1M India" mao.! moth .pi...... elI •• il lJecome. fully ' 10"' 0 and 10.0'1110 Ik... thJad bdlind ."-.... . ~ II d.. Th t'bbon. is t .. . .. I ' _ I _.1__,_ oI"t... d """",h 10 .n 11...... - a ...._ ... -, l io o ...h ch o r .,,(ked ( 0 ..... " '1 - meal or cvrO in Ihe a r (thaI . be . .. p.n io u. ly i"ju ' ed by Olhe, opt.. . in,i)' Of in , roup.. on food Jl'"!, ) ..... IJecome /tao.ily inr...ed .....1..'. 1. With.... r... dIIy.. IM.W Iii.. 1 9~ hold! .IKI .mall .h,I,'" ",.••t. or C.I.fp,II..., .m.f'• . Th... Ill...... Medll.uen••n Flour te.d up on If.in• . , f.in pfodu<;l.. Moth d ried fruitl. nUI...nd • •afh.. . id. '·.finy or rond ..uff•. The Medue" a...." flou, molh...... h.n fully , fo..n. lh. IlIf"" i. A"Q,o:""'Q klWlr"wll" (Z.llu).' h•• a ollnul half .n in. h Inn, and i. d in y ..in,.p,ead o f . ii,hll)' I... Ihan I "'hi'e, ...m.limn \'a,yin, 10 g' eeni'" inch. In hind..in, ••,•• d in y ...hit. , and pinki. h hu•• ,f ig. 18 8). n . ,a"'a and Ih. [o,...;n,. _ ...hich .Ion• •ho.. •p;n. a ..Ikon cocoon and If. ,,,fo,m. ..·h. n Ih. mOl h i. nol flyin, _. ' •• ,_ ,, _,_ _ Ufo.l_.... _-..-.I_.... _.ton ...... _--- 1 6 AGRI CULTURE HANDBOOK NO. 500, U.S. DEPT .OF AGRICULTURE machinery in flour mills and causes milling o perato rs to stop. In mills that have an annual fumigation. this insect is no longer a major prob lem. Although it prefers flour and meal, the Med iterranean flour moth atta cks gra in . bran . ce rea l product s. and many other foodstuffs. The female moth lays small white eggs in accumulations of flour. meal, or waste grain. Within a few days. a small larva emerges fro m each egg (fi g. 20C). When fu lly grown , the larva is abo ut half an inch long and is whitish or pinkish, with a few small black spots on the body. The full grown larva spins a silken cocoon. in which the insect transform s into a redd ish-brown pupa (fig. 20D). Later. the ad ul t moth emerges from the pu pa . During wa rm weather, the Mediterranean flour moth requ ires 8 to 9 weeks to pass through the egg, Figure 19.- Ear of co m with characteristic larval. and pupal stages. loose webbing left by larvae of Indian meal moth. This moth rarely attac ks sound grain Three other insect species occa but often attacks grain already inj ured by sionally infest grai n or cereal prod other grain pests. as shown here. Webbing ucts. T hey a re th e almo nd moth, develo ps only when grains are not mo ved Cadra cautella (Walker), the tobacco for some time. moth, Ephesti a elu tella (Hubner), and the ra isin moth , Cadra figulilella (Gregson). Of the three, the almond pale leaden g ray with transve rse, moth is the most troublesome pest wavy. black markings (fig. 20A. 8) . (fig. 18C). It is commonly found in T hi s flour moth is a nativ e of seed stores and is a serious pest of Europe. It wa s first found in the rough rice and grain sorghum in the United States in California in 1892. South, Since then. it has become widespread over the country and for many year s Meal Moth was considered the most tro ublesome pest of flour mills. Th e larva spins The meal moth, Pyralis f arinalis silken thread wherever it goes and Linna eu s,? is brown ish, somewhat webs and mats together particles of larger than the Indian meal moth foo d o n whi ch it is feeding. The (th ough it varies in size), and usually ma tted flour some ti me s dogs the has a wingsprea d of about I inch. STORED GRAIN INSECTS 17 -. 'w''" 0 BS ·J078 Figure 20.- Mediterranea n flour moth: A . adult (dOfSOII view) with wings spread; 8 . adu lt (side view) in resting position: C. larva; D. pupa (enlarged); E. abdo minal joint of la rva (enlarged). Adult moth has a wing expanse of slightly less than I inch. Figure 21C shows the characteristic larvae cut through bu rlap sacks and markings or patt ern of the forewings. can damage them grea tly when heavy T hey a re lig ht br own wi th d a rk infestations develop in the sack ed brown patches at the bases and tips, material. Figure 22 shows the charac and each forewing has two wavy, teristic "webbin g togethe r" of infested tra nsverse white lines. seeds (in th is instance navy bean s). Th e meal moth is widely distrib Figure 23 shows the tendency of the uted and, in the larval stage, is a gen larvae to spin th eir whiti sh silken era l feeder upon cereals, cereal prod cocoons on the outside of grain sac ks ucts, hay, and many types of dried where the sacks tou ch one another. vegetable matter. It is usually found When the larvae cut sacks, the seeds in damp basements or in other places fall out and lodge where the sacks where accu m ulatio ns of d amp, touch. In such places, the seeds are spoiled grain, bran. or meal a re usually heavily infested. found. Though it prefers material The meal moth larva is whitis h, that is damp and in poor co ndition, and, when fully gro wn, is about I the meal moth may attack a nd inch long (fig. 21B). Th e larva shows seve rely da mage so und wheat or a contrast between the black of the cerea l products, if these mate rials are head and the first body segment and stored in mo ist places or have a rela the white of the remainder of the tively high moisture content. body. The body of the larva is often Meal moth larvae so met imes tinged with orange toward each end . attract much attention because of The larvae spin peculiar tubes of their capacit y to "web-up" and bind silk that contain mixed particles of together seeds of various kinds. The food material. T hey rest in these 1 8 AGR ICULTUR E HANDBOOK NO. 500, U.S. DEPT . OF AG RI CULTURE A B c B\·.'071J Figure 21. - Mt'al mot h: A . pup a an d (ab o ve! web bed grai n mass wit h portion 01 pupa pro trud ing; E, two well-grown larvae a nd (right) smalle r larva: C. two ad ult mot hs. Markings o n for ewings easily distinguish this insect from ot her grain pests. Magnified a bo ut 1· 1/ 2 times. tubes. which are very tough. and feed week and lays 200 to 400 eggs. In from the openings at the ends. Wh en summer. the period fro m egg to adu lt fu lly grown. th e larvae lea ve th e is 6 to 8 weeks. tubes. spi n silke n coc oo ns (a lso often co vered with food pa rticl es). a nd transform into pupae (fig. 21A) from which the adu lt moths lat er emerge. The femal e moth lives abo ut I B\; -JIHI Figure 23.- Whitish cocoons spun by meal moth lan..ac on sid e of sack pr evio usly filled B ~ · 3 () 1! () wit h infested seed. Note da rk pupae with in Figure 22.- l':av)' beans. webbed to gether by cocoo ns, vetch seed ..... ebbed to sa ck by lar meal mo th larvae, ad here to sac k. vae. a nd (cente r) adu lt moth . STORED GRAIN INSEGTS 19 GRAIN AND FLOUR BEETLES Cadelle with the abdomen terminating into two dark horny point s (fig. 248) . The The ca delle, Ten ebroides mau larva bod y is a dirty or cha lky white. ritanicus (Lin nae us),s is an elongate. and the head. thoracic shield. and oblo ng. flattened. black or blackish two horny points are black . beetle about one-thi rd of an inch long T his insect is widesp read over the (fig. 24A). It is sometimes called the world a nd is freq uently fo und in bolting-cl o th beetle becau se of its mills. gran arie s. and sto re ho uses. habit of cutting the silk cloths of where it infests flour. meal. and bol ting reel s and redressing mach ines grain. Both the larv a and adull feed in flour mills. on grai n and have t he destructive Th e cadelle larva is one of the habit of going from kernel to kernel largest of the grai n-infesti ng insects devouring the germs . The cadelle is and is eas ily recognized. It is about one of the longest lived of the insects th ree-fou rt hs of an inch long. fleshy. th at attack stored grai n: man y of th e adulls live for more than I year and "Coleop tera. ' ·rog o!'itidilc some of them fo r nearl y 2 yea rs. A HN·30lSl PN·5177 Figur e 24.- Cadelle: Ufl, adu lt, about one-third of an inch lo ng; right . larva, abo ut three-fourt hs of an inch long. 20 AGlllClJLTlJllE HANIlIlOOK NO. eoo. Uil OF- no' or AGIl IClJLTUIll': T ~ I...... k becl.. ""i_" ...... '" her I,fe and. und.... I• •onob""","" .n1l Y' .bou, 1.000 CW n.. I ,.. e1u...... '" ...... cp;> ill lood ,eriaL .. bid. lulteh .. 7'oIO '· "" ....' hcf. 110c romplftc: .Ioci. " 0,,' 11 ,,, 1 10 14 mon,ho ..... ,I>cn _ k ...... --.sed p"'" in .. hich ' 0 I..,.J_ ,nu, 1M 1"'p"1 ...,.. 1hq I.....ucnd' baR "" 0 ,he limb.... '" 'llc ho n or 0'"" ,.c.p'ad. Ih., ho lch ,h. i" lnled ma'C'rial. ""'h ,I>c ...... a"'" a.hlll u n Ii... r", I"", pcri<>d • .. i,hou' food .nd " h.n uma,n hidd.n in ,h. ,, """'.. o,k " I ' h. hin 10' a I"n, ,im• • f1., ,h. ~'.'n ha. bcC1I te"mo.ed, When ...... ,.in i. pu, ,n'" ,he hin. i' hccomc. inl"'ed ,na ."tpn"n.ly l!Io" 11m• ...... " _ ~ . h i ." n • •_ ••• _It _ . sawloothed Grill" Bee n. ,...... The ..._ 1Iocd , ra,.. becl le, ()f-r -- _- _po' b,' ...... u fL "'.....k· .. .- of oAc bnl k...... '" .be coo- ...... 1l&II , ...... pnl' II . \left.. "Y' aJ 10 ;,;, CU" She d .... 1111. lor_.. bert.. aboul 111 of llIom Iocrtdy ."""" 1110' I....,hcuff OC ...... It p ,n. h I""" luck> lhem inlo .. erc>>a: irt . kcmcl lhe pccoIiar oIlUCl"te" of IIIc 'honoa. of lIJ.in. 1M . man. oIC1ldc1. ..II" • ..hi IuItd1 ill ) 10 , dll)" ,inn. 01\ h .id. If"" 2~) , I, . ' loId .. Tile ...... ',;n' Ia..... del ...... loIl· in botll the ·aI . tid adul' ...... all ...Ihin ••in. 1e .,ain \luI . ra.l aboo' f<><>d of ,,",..ahl. on,in• •"f'CCially aa,\'Cly .r.d feed. Oorin• •ommc'. • ,.in and . ,.in p,,,do< '. _h a. Ih.,., hccomc folly n in .boo, 2 noo ... m•• I•. b••• Hu ' 1,1Od•.•'ock ..'tth . 1 h. mllu" Ia lh. n oon· .nd poollry feed.. <"p,a. nUl mel'" .1..,<1 del;". ,. «,.""nlik. <"...,in,_ car.d'n, . r.d dried !rUIl• . by j" ,nin. 'ollclhn .....n , raint '" Thc adol" h ., on .n a••,•••. to I.... m..... 01 food"ofr• • i,h a tli Th. !lah" . and d dop""'" of ,h• ...... •p«in arc .im,I 1m, lh, me,· ."' .daled 'p«In. ,h. mad'ant chan. , •• ,n I>a1k Iayo n n ~' "".-half ,rain b«11r. Or"""ph,h., .....'./1'", 1o ' .. o-tl....h • • mall)' cllI" (hUHIl: .. " ftC" CORfu....! ,",10 'ht' ..."., >l1lN ,r.,.. bc'eIk II It ~ Squarenec:hd Gr.ln rom I) !(lUnd In 'filII I h.il" ,IK Beetle .....loolMd ,no,.. Mrilot and . p rn~ to p .....-- • -,,-._ ... __- __...._-...__ IAt. .._ .... 22 AGRICULTURE HANDBOOK NO. 500 t U.S. DEPT. OF AGRICULTURE Bar in appearance to the closely related squarenecked grain beetle, but is shorter and stouter (fig. 28). Though of worldwide distribution, it is not important as an enemy of stored grains. It is attracted to damp and moldy grains, where it feeds on the molds. This insect is rarely found in clean grain. Mexican Grain Beetle The Mexican grain beetle, Pha raxonotha kirschi Reitter ,10 is a highly polished, deep-brown beetle about three-sixteenths of an inch long. It somewhat resembles the con fused flour beetle in general appear ance but can be readily distinguished from that insect by its more polished surface and longer antennae (fig. 29A). BN-308S This insect is common in Mexico Figure 27.-Squarenecked grain beetle adult, and Guatemala, where it breeds in about one-tenth of an inch long. grain and grain products, but it is not known to be established in the United a great variety of plants. It is one of States. the most common beetles in stored corn in the South and, in the corn Siamese Grain Beetle fields, is always found on damaged or exposed ears. The Siamese grain beetle, Lopho The immature stages closely cateres pusillus (Klug),8 is a flattened resemble those of the sawtoothed reddish-brown beetle slightly less grain beetles in both form and habit. than one-eighth of an inch long. It is The larvae have the bad habit of characterized by the much flattened devouring the germs of the seeds in margins of the thorax and wing which they breed. These insects covers (fig. 30A). develop from egg to adult in about 3 This insect first appeared in this weeks. country in exhibits of rice and cereal from Siam, Liberia, and Ceylon at the Columbian Exposition, and it is Foreign Grain Beetle now well established in the Southern The foreign grain beetle, Ahasverusadvena (Waltl),9 is a small reddish-brown beetle somewhat sim- IOColeoptera, Languriidae. STORED GRAIN INSECTS 23 pest of stored grain, and the adult is a p pare n t 1y unab1e to su rv ive in sound, uninjured grain. It follows up the attack of the more vigorous grain pests and is frequently found in enor mous numbers with the rice weevil. This insect is a scavenger and often infests grain and meal that are in poor condition. The females deposit small white eggs in crevices in the grain or drop them loosely upon farinaceous mate rial. The larvae are particularly fond of the wheat germ, and, in infested grain, many kernels are found unin jured except for the removal of the germ. The larvae also feed on dead insects. When fully grown, the larvae form cocoons of a gelatinous sub stance to which food particles adhere. They transform into the pupal stage in these cocoons and later emerge as adults. Under favorable conditions, BN-3086 this insect may develop from egg to Figure 28.-Foreign grain beetle adult. adult in about 5 weeks, but the average period of development in summer is about 9 weeks. States. It is commonly found in rice A related beetle, C. turcicus mills in Texas but does not cause (Grouvelle), resembles the flat grain serious damage. beetle so closely in appearance and habit that it is usually confused with Flat Grain Beetle that insect. This beetle, also, is cos The flat grain beetle, Crypto/estes mopolitan and the females of the two pusi//us (Schoenherr)," is one of the species are so similar that it is almost smallest beetles commonly found in impossible to distinguish between stored grain. It is a minute, flattened, them. The males, however, can be oblong, reddish-brown beetle about distinguished from each other by the one-sixteenth of an inch long, with length of the antennae. The antennae elongate antennae about two-thirds as of the C. turcicus male beetle are as long as the body (fig. 31). It is cos long as, or longer, than the body, but mopolitan and is one the the com the antennae of the flat grain beetle monest insect pests of stored grain. male are only two-thirds as long as However, this insect is not a primary the body. 2 4 AGRICULT URE HANDBOOK NO. 50 0 . U.S. DEPT. OF AGRICULT URE 8 :\·3081 Figure 29.- Mcxican grain beetle: A, adult; B. larva: C. pupa: D. leg of larva; E. antennaof larva. A, B. and C enlarged about 8 times: D and E greatly entarg ec . Rusty Grain Beetle Confused Flour Beetle A thi rd species, the rusty grain Th e confused flour beetle, Tribo beetle, Cry p t o lestes [e rrug ine us lium confus um Jacque lin du Val," is (Stephens).' is similar to the Oat grain a shiny, flattened. oval. red d ish beetle and C. turcicus beetle in brown beetle ab out one-seventh of an appearance and habit, but differs inch long. Th e head and upper parts from them in the antennae (fig. 32) of of th e t horax are densely covered the male beetle. which are not more with minute punctures. The wing th an half as long as the bod y. This covers are ridged lengthwise and are speci es is more resistant to co ld sparsely punctured between th e ridges weather than the oth er two species (fi g. 33). T his insect is distrib uted a nd is mo re commonly found in stored grain in the No rthern States. "Coleoptera. Tcnebriomd ac. !rfOREDURAlS ISS],rtS . ~~ A \ • • A I . ( I, ) I I , ~ c A ",.""" h • • f<.'O , 10m,., ",001,• . ' . • nI of od.~. C '",,'• . f'. "" po ,... ", ~ r Ih~ ..'o tld and i. \Cry .hunda.n ' ht ""J/lOlU .hi ",."')'. II i> a ,...... al f«dor f. ti~ ....'cnal .nd \I undoublcdly' ,hot 11>0II ahun donl . nd inJ.... n"".'n>ca J'e'I of flour mIll. in , hot t"n,.cd St.l... II IS r.....nd ,n , ranann. mill.. ...~hou'". • nd ... horn... ~ ra i n n t ~ ra , n r todoch a . ~ .torcd. Th. ""..aB~ lifo of ' h... 1>«110' i, . h" UI I y..... hut . um. h;r., ~ I>«n knm.n 10 l..,~ •• lun, ., ~ l ..... q mon,h., Thot f~ l ~ lay. an ••• r. ,~ ul .bout &'50 ~ ,,.. " htdI .'" . mall and .. hn~. ~y' ,n flour or nlhcr food ....tmal ,n " Inch ,hot adull.l,,~ T~ ' .r~ t Red Flour Beetle I h. 'M n"u' ",: I he p",n,,'um " .. "j~., "'he middle i, p , i m . " I ~ a 1"<''' " f milled r'''d..... 1he d,II. ,...... hcI",..n the ' " '' II ,. r'"'""' ,n ,'a'" .h,pm. n". ' J"«' '"'' aU' . h" .. n ,n fl,uU' ,14 .. he,• •, aU...,• • ,, "l}' ~ ..'" d.. " and I hI> 'n.....1" e' ''' ' ' and~ ...."'..,ed ,he ."'1.'..... ,,{ h",. ... ~. a ' '' ' . h.".,.. " l1 h thc ".nlu'Cd n....' "0011. and ",. ...., a p "ma ~ ,...... ,,' "'m.....taal ha • •,mda ' I.cd,n, and h,c.d,n, .h,p",",," h,;"h l1 . I h. 'mma''''. "a,... or ,h. American Black Flour '"'' ,n••:" ••rc ... ,"n,I., ,ha, 11 '" ,mp" .... ,hl. I" d ,,"",u,..tI hot"' ..... Beetle ,hcII' I hc .k'd"pm.nt..1 rc.i<>d l he A...... n hlac' flo.",. hoo1k. II. "" 'W h ' .001 ..1, II~ ..>me- T"Io ~ _" ~ _ . I _"-'-0_''--'__ = ,...,__ ,...,--,--,--,, - _. _,...,,--- 28 AGIUCULT Ul I ~ IlA !'oI I:lBOOK /';0. MO , ua. DEn , Of AGRICULTUln; ~ ;' "" JS.- H"", 0«1"" .<, MI'I..-i",o bI"l 0"., 0«11, IId nH. S. Iuo.".dnl /In., _ " IId , Lt .C.d,~ Thi. i n"~ l i••ddom found in t:~Il~nl>oo ~aan , anolh" '1'«'" of inj u riuu. n umh." and i. h ~ no lhi. dCllltueti,·. group of nou' 11«11••, m. an, a. " ·'d.-p,. ad a. T, m njwum ,,·u ,« . ml~ ,.ponod from ~ " n lt ... L and T. cQ.l1an t'Um, It o than one-eighth of an inch long. It is Smalleyed Flour Beetle somewhat similar in form to the con fused flour beetle but is narrower and The smalleyed flour beetle, Pal is pale yellowish brown (fig. 35B). orus ratzeburgi (Wissmann), II is the The beetle is further differentiated smallest of the flour beetles that from the confused flour beetle by the infest grain and grain products in this peculiarly shaped antennae and the country. It is tiny, somewhat oblong, minute canthus behind each eye. flattened, shiny, reddish-brown beetle The longheaded flour beetle has about one-tenth of an inch long (fig. been reported from most parts of the 35D). This insect occurs throughout world as having infested wheat, rice, the world and is widely distributed in corn, barley, rye, flour, and similar this country. It breeds in grain and products. It was first recognized in milled products and is frequently this country from specimens collected found in flour-mill basements. in Texas in 1908 and is now wide spread in the Southern and Middle Western States, where it is common Depressed Flour Beetle in rice and flour mills. This beetle The depressed flour beetle, Pal infests grain and grain products in orus subdepressus (Wollaston),II is the mills and causes the same type of similar in appearance and habits to damage as that done by the confused the smalleyed flour beetle. It is flour beetle. slightly larger than that species, and the sides of the front of the head are strongly reflexed and extend back ward to conceal the front portions of the eyes (fig. 35E). In the smalleyed Slenderhorned Flour flour beetle, the sides of the front do Beetle not extend backward. The depressed flour beetle, also, is cosmopolitan but The slenderhorned flour beetle, is much less common in the United Gnatocerus maxillosus (Fabricius), II S tates than the s malleyed flour is closely related to the broadhorned beetle, except perhaps in the Great flour beetle and is of similar form and Plains. appearance (fig. 35C). It is about one eighth of an inch long. In addition to Broadhorned Flour its smaller size, this insect may be Beetle distinguished from the broadhorned flour beetle by the slender incurved The broadhorned flour beetle, "horns" with which mandibles or jaws Gnatocerus cornutus (Fabricius),II of the male are armed. Its habits are owes its name to the peculiar struc similar to those of the broadhorned ture of the mandibles, or jaws, of the flour beetle, but it is less common in male beetle, which are armed with a the United States and is more or less pair of broad, stout "horns." It is a confined to the Southern States. stout, reddish-brown beetle about 3 0 AGR ICULTURE HANDBOOK NO . 500 , U.S. DEPT . OF AGRICULT URE o ne-s ix th of a n in ch lo ng. and it Larger Black Flour closely resemb les th e other flour bee Beetle tles in a ppearance but is easily dis The la rger hlack flour hectic, Cy n tinguished fro m them by the peculia r aeu .'i anguJtuJ ( Le'Conte j.' ? described structure of its jaws (fig. 36). It is cos in IX52, was little known as a pest of mopolitan and is common in all parts stored grain and grain products until of the United States, except in the 1 9 .~ 9 . when it was found in a flour Great Plain s. where it is co mpara mill in Seattle. in stored wheat in tively rare. This insect prefers to feed Kansas. and in sto red co rn in Iowa. in flour and meal but is found in a It is now fairly common in farm va riety of grains. T he ad ult beetles sto red g rain in the Nort h Central freq uently live for I yea r o r longer. States. It is a stout. reddish-brown or The fe ma le la ys 100 to 200 small black hectic about one-fourth of an wh ite eggs which hatch in 4 to 6 days inch lo ng (fig. 37) . Th is insect is in warm weathe r. The developme nt known to live fo r 6 months and may period from egg to adult is 6 to 8 week s. B'\-J094 1i:\"· JfN5 H:"-J096 Figure J6.- Hroadhorned flour beetle: l eft . larva: C'f'fI{f'r. pupa: ri1(lI/ . adult . Adult is about one sixth of an inch tong. ~-r OR un GRAIN INS f:L-rS ...... t? 1M,.. IIbd ""'" . • _ ,....." ••~h "' .. -" "'"• II.. ro. ~t I...... I )' ~ar und~ r b , or. .. cel ., ! EGGS OF FLOUR AND GRAIN INSE CTS Th ~ B\ -JOl1 H Fi g ure JIL Egg s o f fl our a nd g rai n i n ~ c d s : .-1. road ho rned flour beetle: H, cadellc: C. Mediterranean Oour moth: l ) , confused flour beetle. Photo greatly enla rged. MEALWORMS The term "mea lworm" applies to in the United States, it is abundant th e larvae of severa l beetles of the only in the Northern St at es. family Teneb rionidae that are noc T he a d u lt is a po lished d a rk turn al and frequent dark places. Th ey breed in refuse grain, coarse cereal, brown or bl ack be et le some w ha t more than half an inch long (fig. and mill products tha t accumula te in 39A). Its thorax is finel y punctured, dark corners, und er sacks, in bins. and its wing covers ar e long itudinally and in similar places. T hey inhabit st riated or grooved. The fema le lays m oist pl a ces a n d a re o fte n found bean -shaped white eggs cov ered with amo ng slightly damp bags. a stic ky se c re tio n tha t ca uses the Yellow Mealworm flour. mea l. or grain waste in whi ch th ey are placed to ad here 10 them. The yell ow mealw orm, Tenebrio Th e eggs ha tch in about 2 weeks and mo li to r L inna eus. !' is o ne o f the slende r white larva e eme rge. The largest insects that infest stored cereal larva e soo n turn yellow and assume products. This insect is cosmopolitan; the fo rm shown in figure 39C. When STORED GRAIN lNSEt"J'S 3 3 A B c F,_ A , " _ '. .... _ ".-111 _ __ ""'D " _ c..- __ 34 AGRICULTURE HANDBOOK NO. 500, U.S. DEPT. OF AGRICULTURE fully grown, the larvae are about I in contrast to the shiny or polished inch long and are yellowish, shading dark-brown or black yellow meal to yellowish brown toward each end worm adult (fig. 39B). The dark and at the articulation of each seg mealworm larva so closely resembles ment. The yellow mealworm gets its the yellow mealworm larva that it can name from the yellowish color of the best be distinguished from that spe larvae. cies by its much darker color (fig. There is but one generation each 39D). year. The adults begin to appear in These two species are often found the latitude of Washington, D.C., in together since they have similar late May and early June and may be feeding habits. The overwintering ,found until late in August. The larvae of the dark mealworm begin to female beetles are quite prolific, and pupate earlier than those of the each may lay as many as 500 eggs. yellow mealworms, and, in the Wash The larvae become fully grown in ington, D.C., area the adult beetles about 3 months, but, instead of trans emerge during April and May. forming into the pupal and adult stages, they continue to feed and molt until cold weather and then hiber Lesser Mealworm nate. Later on, in late spring or early summer, they transform into the The lesser mealworm, Alphitobius pupal stage for about 2 weeks. diaperinus (Panzer),11 resembles the Because the yellow mealworm has yellow and dark mealworms in form but one generation each year and is and color but is considerably smaller. entirely an external feeder upon I t is black or very dark reddish grains, it is not a serious pest. brown and is three-sixteenths to four Screening and fanning will easily sixteenths of an inch long (fig. 40A). remove it from grain shipments. The The larva is yellowish brown and well-grown larva, however, can do closely resembles the young larva of serious injury to whole grains under the yellow mealworm in form and certain conditions, when grain is held appearance (fig. 40B). This insect is for long periods without being cosmopolitan and is commonly found moved. in flour-mill basements in damp or musty flour or grain. It prefers grain and cereal products that are slightly Dark Mealworm out of condition and is commonly associated with poultry feed. The dark mealworm, Tenebrio obscurus Fabricius.'! is very similar Black Fungus Beetle in form, size, and color to the closely related yellow mealworm. However, The black fungus beetle, Al the adult is a dull, pitch-black beetle, phitobius laevigatus (Fabricius), II is STORED G RAI N INSE(TS A _ "---" almo.t id. ntic.1 in .pp•• •• n.,. 10 th. Redhomed Grlln Be.tl. I. .... mu l...o.m . nd h.. , imil.. h.bin , II p.d . .. dlmp, moldy S••in Th• •edh" med , ••in h"" II e. PI",y" .nd cer ul p , od ~ cJI Ind doe. nol dn.." , ../Iro , ... ( Slu.m). " i •• ca ~ ", ",nOllI d. mli. 10 so~ n d , ••in, hroad ly "".1 """'I. IhShtly In. Ilion Thi. ;n>«t m. y b< d i. t j llg~ iohed f.om on..fOllnh of .n inch lona . n i. ' B E D 8~ · ] I OO Figure -tt.c-Black fungus beetle; A . larva; B. pupa; C. adult; D. caudal segmen t of larva: E. lat. eral plate of pupa. l.an..a i"i about I inch long. li:\ -5179 F igu re 42- Redh o rned grain beetle adult . abo ut one-fourth of an inch long. STORED GRAIN INSECTS 37 DERMESTID BEETLES In general, the dermestids are a weeks, and each female lays; about group of beetles that scavenge and 100 eggs. This beetle is cosmopolitan. feed on animal matter.. Certain spe cies, however, belonging to the genera Trogoderma, Anthrenus, and Trogoderma Beelll!a 12 Attagenus, vary their diet by feeding The best known member of this on farinaceous materials. They are group is Trogoderma inclusum freq uently present in flour mills, farm LeConte,12 which is a common pest granaries, warehouses, and similar of grain, seed, and other stored prod places where grain) and grain prod ucts in the Great Plains SUates. The ucts are stored. adult beetle is one-fourteemth to one Black Callpet Beetle sixth of an inch long. 1"hlc female is about 1-1/3 times the size of the The black carpet beetle, Attagenus male. The beetle is redtilLsii brown to megatoma (FabniWius),12 is a small, black with indistinct pater markings oval beetle two-siateenths tal three on, the wing covers. sixteenths of amiDdllong (fig, 43A). The larva is stout, 31Dd, at rest, the The head and tJlDrax are black, but back is yellowish brown (fig. 45). the wing coven; are black or dark However, the areas between the seg reddish browm _ are covered with mmt5, which are visible during move short hairs. Its; tep and antennae are mmeJIt., and the underside are very pale dark yellow; The larva is very charac ydlow. The last three segments of the teristic and can be easily necognized. body are almost covered by tufts of It is reddish or golden brawn, is cov dense, specialized hairs. The fully ered with short, scalelike, appressed grown larva mag attain a length of hairs, and: bas a tuft of !bog hairs at one-fourth of an inch. This insect the end of the body (fig, 44). larva is difficult to distinguish from The Larvae are often found in the larvae of rated species. abundance in cracks mthe floors of The adult female beetle lays up to warehouses where foodstuffs have 96 eggs. The life cycle varies from 7 accumulated. In the spring, these weeks to several years, depending larvae transform into adults, which upon the temperature and the food swarm over bagged material stered supply. there. Because the larvae of the black Trogoderma glabrum (Herbst) is carpet beetle develop slowly, there is very similar to T. inclusum and is only one generation each year. If con found in similar situations. The adult ditions are unfavorable, the life cycle lacks the longitudinal pale markings may be prolonged to 2 or 3 years. on the midportion of the wing covers, The adults, which emerge in the and differences in the eyes and spring and early summer, live 2 to 4 antennae of the two species can nor- 38 AGRICULTURE HANDBOOK SO, 500 . U , ~ DEPT, or AGRICULTURE __B A f _.I.- _ _ ... A. ~ .. , i ' _ H.l _(. •• _ ..... __, Do ...... _ ' 0<._ 01 __ __ 01c_ D, 01 F""" """ Ai. ' " STOR F. O CRAIN INSf:CTS 1,."" " ,_ I.",. or ~,, ' l '''r<' """" I" '" ,.It,>0, "r h",.,. • 1><,", ,••,h"'" 01 .n '"," "'. "", 4< I.,,, .,, 1>" ."dffmo ;"..1.,,"," I an eradication program was started. grain. The larvae crowd into thecrev By 1961, active infestations were ices of building, bins, and so forth, eliminated, and strict quarantine and are difficult to reach with measures have kept the beetle from insecticides. Since this beetle has lim becoming reestablished in the United ited mobility, it spreads principally States. through the agency of man. This beetle prefers dried vegetable Other species of Trogoderma in matter to animal matter as food but this country that may be confused will attack almost any kind of either with those mentioned here are T. material. Grain damaged by the grassmani Beal, 1: omatum (Say), T. khapra beetle has somewhat the same simplex Jayne, and 1". stemale Jayne. appearance 'as grain attacked by the .All these species are .sometimes con lesser grain borer. fused with the Anthrenus species, Under favorable conditions, the which are not grain pests. The varied khapra beetle -breeds so rapidly that carpet beetle, A. verbtUCi(Linnaeus), the larvae often appear in large num .however, has been found in mills and bers in the surface layers of binned storage facilities (fig. 43Q. SPIDER BEETLES,13 Several species of beetles stored grain and all types of:p-ound belonging to the fanHly Ptinidae are cereal products. The adult beetle occasionally foun·d infesting grain appears in warehouses in the .spring and cereal products.. They attract and lays eggs in flour, feed. or other attention by their peculiar, spiderlike cereal products. The female lays form. These insectsare rather wide about 40 eggs. Under favorable con spread in distribution but are rarely ditions, the development period from abundant enough in the United egg to adult is about 3-1/2 months.. States to cause serious damage. The full-grown larvae construct char acteristic silken pupal cases, which Hairy Spider Beetle are covered with food particles from the food material in which they The hairy spider beetle Ptinus vi/ occur. liger (Reitter),'? is a reddish-brown An allied species, P. raptor Sturm, beetle marked wi th four irregular is about as common in Canada as the white patches. It is about one-seventh hairy spider beetle. of an inch long (fig. 46). This insect is a rather common pest in the Prairie Whltemarked Spider Provinces of Canada and is occa Beetle sionally destructive in the adjoining Northern United States. It attacks The whitemarked spider beetle, Ptinus fur (Linnaeus), is also found I3Co)eoptera, Ptinidae. in the Northern States and is some- srORE D GRAIN INSEcrS 41 '. the United Sta tes but is rar ely found here. It is very similar in general appearance and habits to the brown spider beetle. <.. \ The Amer ican s pi der bee t le. Mezium americanum (Laporte). is a small spider beetle of striking appear \ a nce. It ha s a sh iny. su bg lo bula r body that distinguis hes it from the precedi ng spider beetles (fig. 48). It is somewhat of a scavenger and feeds on dried animal prod ucts and pla nt matter. It is no t an impo rtant pest of sto red grain o r grain prod ucts. but it is occasionally found in mills, ware ,. houses. and dwell ings, • A closely related species. Gibb ium H ~ · 3 1 02 psvttoides (C zenpinski), resembl es the Figure 4b.- Hail')' spider beetle adult. ahout American spider beetle in appearance one-seventh of an inch long. and habits and is found in similar sit uation s. It may be distingui shed fro m tha t insect by the head an d thorax. what more abunda nt than the hairy which are densely covered with small spider beetle. which it closely resem bles in a ppearance a nd habits (fig. 47). It feeds on both a nima l and plant matter and atta cks flour, feed. grain. a nd miscelianeou s foodstuffs. It is ra re ly a b u nda nt e nough to ca use serious damage. / ,I Brown Spider Beetle The brown spider beetle. Ptinus clavipes (Panzer), closely resembles the whitemarked spider beetle in size. co lo r. general appearance. and habits. It mal' be distinguished fro m that beetle by the absence of white markings on the wing co ve rs. Other Spider Beetles 8' · ) 103 Figure 4 7 . -W h i t ~ma rk n:l spider b«1 1~ adul t The Australia n spider beetle. Ptinus female. The elo ngate-o val male is not so ocellus Brown. has been reported from con spicuously marked as the female. 42 AGRICU LTURE HANDBOOK NO. 500. U.S. DEPT. OF AGRI CULTURE B' ·30H Figure 48.-American spider beetle adult. Photo enla rged. sca les and scalelikc hairs. This species States. whereas M. affine (Boieldieu) reportedly occurs only in the extreme is the co mmo n form in the Northern so u t h e r n portion of t he ni te d States an d Canada. MISCELLANEOUS BEETLES Twobanded Fungus Beetle Hairy Fungus Beetle The two ba nded fungus beetle. AI The hairy fungus beetle, Typhaea phitophagus bifasciatus (Say).!' is a .Herc'o rea (Linnaeus),':' is frequently small. handsome. elongate-oval beetle found in cornfields. where it is appar slig ht ly less tba n one-eighth of a o ently attracted to the decaying ker inch long. It is reddish brown with nels of exposed cars. After corn is tw o broad bl a ck hands across the harve st ed a nd shelIed . it is o ften wing C(WeTS (fig. 49 ). This insect is hea vily infested by this insect. but distributed over the world and. as a there is little feeding on undamaged scavenger. generally feeds o n such grn in, Thi s beetle is cosmopolitan materials as fungi and molds in refuse and is fou nd in all parts of th e United gr a in a nd gr ain product s . a nd St ates in dwellings. wa reho uses. decaying vegeta ble matter. It is fre stores. fl our mills. granaries. and sim quently found a ro und mills an d ilar places, storehous es where waste material is It is a small brownish beetle about all owed to accumulate and in wet or one-tenth of an inch long and is cov damaged grain in the holds of grain ered with ha irs (fig. 50). It rat he r ships. T he larvae have been reared in closely resembles the dru gstore beetle m o is t c orn meal a nd in s poi led cereals. 43 II n ~ or "''''"j'''' ' , un and ",her ''1'''" I."'. I",m, and ,n Ih.....1' . ..dm, from ,nju re d pl.nt> II " ,n Il" n c r ~ l .1'''''.'.''''. but " >mallcr (fiB- ~I , n Il' in_ , ,'an al,, ' I>e e. "I} d"l in ~u "h .d f,,,m ,h. d 'u ~,lO ' . hec,l. b) tbe ' No pe ur it. an,•..,,,.<, "''' Hob arC . I. , al. ,n, lcad ur "r. ~u · l arl ~' ",,,al. _ Co rn Sap Beetle I he ,'",n ' 01' "..tl•. C"'I'''I,hdU> JlmiJi~I'" (}-. hri.;u.),'· rna) h. l udil)' r.<"Ini, cd h)' II , ptluliar " ' nl .",n.. "h'cnk. • " h ", hln roh..nl . ,n, ....' . .. and It onc-I 1 __ ...... , _ ...... _ .'_ _ _ 01 .. _ -' \.j A(JRIC UL-nme IIA NOI,U()K so. WO, U,S. m:PT. ()f AOIiICULTUH. E I"" ...n all o,cr. II> haM. arc 'or) ma ~' Ial' a' ma n~ a. IllJ CJ.l!'. Tb, "mIL., '0 , 110"" 01 tllc to"".. ' 1 " ,.._. _ .. /Iff, ..... ,_ o'F, ..... ' 01o I ...... " ~.. _ .. , ._'..~... ,, n,.... ' .... ' , ...... -,.,.,j -. ,.... _.". '" - ....,.' ...... 16 AtJlUCULTURE HANDBo o K :-0, bOO. U. S OEPT. Of AOlllC ULTURE ~ ' < ..un " ..o k "«,I<, r. n I~"" ( hil I, ~I'ld T 'aN" 1(; " ..... " BOOKl-I CEORPSOCIOS (i , . ,n .nd g, a, n p,,,du.,. a,. h,.,kli.., n",n, In lh.i , ,.. ~ ' < ..un " ..o k "«,I<, r. n I~"" ( hil I, ~I'ld T 'aN" 1(; " ..... " BOOKl-I CEORPSOCIOS (i , . ,n .nd g, a, n p,,,du.,. a,. h,.,kli.., n",n, In lh.i , ,.. bodied, louselike insects with fairly large heads, poorly developed eyes, and long slender antennae (fig. 56). These insects are about one twenty fifth of an inch long. They feed on a great variety of organic matter, both of plant and animal origin, but are troublesome through their presence alone, not because of the actual damage they cause. Some females are believed to reproduce without mating, but males are sometimes found with them. Each female may lay as many as 100 eggs, and, in summer, the developmental period from egg to adult is about 3 weeks. The newly hatched young resemble the adults in form and gen eral appearance but are smaller and lighter in color. These insects are widely distributed in North America and Europe. A closely related species, the larger pale booklouse, Trogium pulsatorium (Linnaeus), known as "the death watch," is similar in appearance and BN-3109 habits and is found under the same Figure 56.-Booklouse or psocid adult. circumstances. It may be dis Enlarged. tinguished from the common book louse by its slightly larger size, dimin tributed over North America and utive wing covers, and well-developed Europe but is not quite so common eyes. This insect, also, is widely dis- or abundant as the preceding species. SILVERFISH The silverfish or slicker, Lepisma to recognize. It is cosmopolitan and saccharina Linneaus.!? is commonly feeds on starchy foods of all kinds. It found in mills, warehouses, and is particularly found in dark, moist, dwellings. It is a shiny, silver or warm situations. pearl-gray insect with three long, tail A closely related species, the fire like appendages, which make it easy brat, Thermobia domestica (Packard), is found in similar situ IlJThysanura, Lepismatidae. ations and closely resembles the sil- 48 AGRICULTURE HANDBOOK NO. 500, U.S. DEPT. OF AGRICULTURE verfish in appearance and habits (fig. 57). This insect may be differentiated from the silverfish by its broader body. It is pearly white and is heavily mottled along the back, with dusky scales that give it a banded appear ance when some of the scales have rubbed off. It is cosmopolitan and, in some areas of the world, is more abundant than the silverfish. The developmental period from egg to adult is II to 12 weeks. BN-311O Figure 57.-Firebrat adult, about 2-1/4 times natural size. COCKROACHES20 The familiar cockroaches are fre North America. It is a large, dark quently found in establishments that brown or black roach, about I inch con ta in cereal products. They are long at maturity (fig. 58). The females particularly abundant in the base are unique because they have short ments of buildings in dark, moist sit wing pads but no functional wings uations, and, when lights are sud (fig. 58A). The males have fully denly turned on, it is not uncommon developed wings (fig. 58B). to see the floors almost black with A closely related species, the them. The oriental cockroach, Blatta American cockroach, Periplaneta orientalis Linnaeus, is probably the americana (Linnaeus). is also quite commonest species found in flour abundant and is the predominant mills and food establishments in form in many flour mills in the Southwestern and Midwestern States. 2°Orthoptera. Blattidac. It is larger than the oriental cock- STORED GRAIN INSECTS 49 BN-3055 Figure 58.-0riental cockroach: A, adult female; B, adult male; C, adult female (side view); D, half-grown cockroach. Enlarged. roach and frequently is 1-1/2 inches characteristic, irregularly shaped, long. This insect is bright sienna reddish-brown double spot in the brown, except for the brownish- center (fig. 59). yellow pronotum, which encloses the 50 AGRICULTU RE HANDBOOK NO. 500. U.S. DEPT . OF AGRICULTU RE / ""'-3111 figure 59.- American cockroach: 141 . adult (do rsa! view); right, adult (ventral view). Enlarged . FLO UR OR GRAIN MITES" T he flou r or grain mites arc pal e. They are of ten fnund in stored grayish white. smooth. wingless. so ft grai n and occasionally increase in bodied c rea t u res. T he)' are micro numbers so rapi dly that the grain scopic in s iz e and have numerous seems to be quite alive with them. long hair on the legs and hack (fig . D uring heavy infesta tio ns. their cast 60). M it e s arc not tru e i nsec ts skins and dead bodies accumulate because the adults have eight legs and i n to fluffy . lig h t -brow n mass e s th e bod y is indistinctly divided int o beneath the sac ks of grain. II these tw o par ts. T he 110ur or grain mites. accumu lations are on a wareh o use usuall y less tha n onc-fiftieth of an floor, they roll up into piles. wh ich inch lon g. arc much smaller than th e move about with each gust of wind. booklice. No other group of grain pests pro duces these masses. Wh en p resent in large numbers. th e flour o r gra in :IAcarina. Aca nd ac. mites promote swea ting. impart a dis- STORED GRAIN INSECTS 51 BN-5180 Figure 60.-Grain mites. Greatly enlarged. agreeable odor to the grain, and may or grain mite, is the most injurious cause damage by feeding. species of mite found in flour, grain, Fortunately, the mites that attack and cereal products in North grain are preyed upon by predaceous America. It multiplies very rapidly mites, which usually become abun under favorable conditions and may dant enough to kill the grain mites in complete its life cycle, from egg to a comparatively short time. If not, adult in slightly over 2 weeks. screening and fanning the grain will Species of the genus Tyrophagus usually reduce grain mite infestations and other related genera, also known to a point where no injury occurs. as flour mites or cheese mites, are Acarus siro Linneaus, known as common in grain. They are similar in the flour mite, common forage mite, appearance and habits to A. siro. 52 AGRICULTURE HANDBOOK NO. 500, U.S. DEPT. OF AGRICULTURE PARASITES OF GRAIN PESTS Swarms of small wasplike insects, on the exterior of the grub or in close of the size and appearance shown in proximity to it. The egg hatches, and figure 61, are sometimes found in the parasite grub feeds on the paralyz bulk grain. Similar insects may also ed weevil grub and destroys it. The be seen on the windows of flour mills developmental period from egg to and other establishments where cereal adult is about 2 weeks. One female products are handled. These insects parasite wasp is known to lay as many are not harmful to grain but are as 283 eggs, but the help usually comes beneficial because they attack and too late to prevent damage to the crop. destroy the insects that infest grain A related species, Choetospila elegans and grain products. Westwood.P is somewhat less com The small parasite shown resting on monly found as a parasite of the same a kernel of wheat in figure 61 is the insects. adult of Anisopteromalus calandrae Figure 62 shows another fairly (Howardj.P the most important common parasite of the grain beetles. parasite of the rice and granary wee This insect, Cephalonomia tarsalis vils. The female wasp can detect the (Ashmeadj.P has habits quite similar presence of the grain-weevil grub to those of the preceding species. hidden from sight within the grain and Figure 63 shows the adult of Bracon paralyzes it with a few thrusts of the hebetor Say,24 attacking flour moth ovipositor. She then deposits one egg larvae. This little wasp is one of the most important parasites of these ~~ Hyrncnoptera, Pterornalidac. ~~ Hymenoptera. Rcthylidac. 24Hymenoptera, Braconidae. BN-3056 Figure 61.-Anisopteromalus calandrae (H.) BN-3113 adult, a hymenopterous parasite of grain Figure 62.-Cephalonomia tarsalis (A.) adult. pests, resting on a wheat kernel. Enlarged. STORED G RAIN INSECTS 53 " B 8'\-.11 14 Figure 63. Uran in hehetor S. adult female . in th ree poses: A . feed ing on body fluids of Mediterranean flour moth lnrvu. with straight ovipositor prot ruding behind: IJ. in position for punctu ring body of larva preparatory to laying an egg: C. with ovipositor well inserted in larva. just before laying an egg. 54 AGRICULTURE HANDBOOK NO. 500, U.S. DEPT. OF AGRICULTURE moths. It first paralyzes the flour moth caterpillar by stinging it several times. It then deposits several eggs on the paralyzed caterpillar. These eggs hatch into small, white, footless, grublike larvae that suck the body juices of the caterpillar. Under favor able circumstances, this parasite develops from egg to adult wasp in less than 2 weeks. BN-3115 The species Venturia canescens (Gravenhost)," is even more impor Figure 64.-Venturia canescens adult Enlarged. tant as a beneficial parasite of the flour and meal moths. This slender wasp has a reddish-brown abdomen, black head and thorax, and reddish-brown to yellow legs (fig. 64). Grain dealers and millers not in The habits of this parasite are frequently find a small, threadlike, somewhat different from all the above white worm, about three-fourths of an mentioned parasites of grain pests. inch long, in accumulations of flour or The adult wasp deposits eggs inside the grain dust (fig. 65). This worm is the body of the flour moth caterpillar, and larvae of a small black fly, Scenopinus the entire development of the fenestralis (L. )26 known as the win parasitic larvae, until just before dowpane fly because it frequents the pupation, takes place within the host. windows of mills and similar es The host caterpillar is not paralyzed tablishments (fig. 66). This worm does and continues feeding until the not injure grain or cereal products but parasitic larva has become nearly full is a predator on other insects found in grown. The developmental period mills and warehouses. A closely from egg to adult is 3 to 4 weeks. related species, Scenopinus glabrifrons Meigen." is also known as a windowpane fly. 25Hymenoptera, Ichneumonidae. 2flDiptera, Scenopinidae. STORED G RAIN INS ECTS 55 H\ -Jll t> Figure 65.- Lan "a of windowpa ne fly. Scenopinusfenestratis ( 1.. ). abou t three-f ourth s of an inch lon g. Lan a preys upon grain beetles a nd mites. ; -<::::- . ~. 1t:"· ) 117 F igur e (l ft , - Windo wpa ne fl y• Sc enopinus fenestralis ( 1..) , adult . HOW GRAIN BECOMES INFESTED Grain may becom e in fested in a gra in moth IS ofte n ext reme ly numher of wa ys. In ma ny g rain de structive. In the more no rt hern growing regions. infestatio n starts in St at es th at ex perience severe win ters. the field before the cro p' a rc har field infesta tion is ncgtigib lc, vested. Th is is. of co urse. particularly In add ition to field infesta tio n. t rue in the South. whe re the rice wh ich may be im po rta nt (d ep end ing WCC\ 'i1 and other insects are ahunda nt o n th e region o r th e sea so n ). there arc in the field at ha rvcsu ime. and in the severa l othe r so u rces of infestation of soft red winter wh eat reg ion of th e stored grain tha t arc of co nsiderable Eastern States. wh ere the A ngou mo is im po rt ance. 56 AGRI.CULTURE HANDBOOK NO. 500, U.S. DEPT. OF AGRICULTURE In all regions, it is customary to Grain may also become infested store grain year after year in the same while moving it in railroad boxcars to bins. If these bins are made of wood, terminal elevators. Many grain cracks and crevices become filled infesting insects live in the grain dust with grain dust and broken grain and and waste grain that accumulate in afford places of concealment for cracks of the floors or woodwork and many insects. Insects such as the in the linings of the boxcars. cadelle burrow into the wooden sides Storage of clean grain in ware or floors to pupate and later emerge houses and elevators that already in enormous numbers. Grain bins are contain infested grain also results in not always properly cleaned; hence, contamination through the move fresh grain stored in them quickly ment of insects from the infested becomes infested. grain to the clean grain. Storing bran, shorts, and other Before shipment, uninfested grain milled feeds in or near the granary is should not be placed in sacks pre another cause of infestation, since viously used for grain storage because these products are invariably infested. these old sacks often harbor insects, Many bins, too, are located in barns as shown in figure 21, unless they that normally contain products in have been sterilized by heat or fumi which insects breed. gation. Certain extensive and costly Temporary storage of grain in infestations have been traced directly country or crib elevators frequently to the use of secondhand, infested, adds to the danger of infestation. untreated grain sacks. Such storage is difficult to keep free from infestation, and clean grain Grain stored in open or poorly often becomes contaminated by constructed cribs or bins may become infested grain brought to the same infested by insects flying in from the place. outside. HOW TO PREVENT OR REDUCE PRIMARY INFESTATION Adoption of the combine har around the door frames of metal vester has reduced field infestation of bins; (4) clean up and dispose of small grain to a negligible amount. litter, waste grain, and feed accumu To prevent infestation after harvest, lations in and around farm buildings; it is recommended that producers (5) apply protective powder, or spray, take the following steps: (I) Store directly to grain as it is binned, or only dry grain in weathertight, fumigate promptly after binning; and rodent-proof bins, preferably made of (6) inspect the bins monthly and steel; (2) clean out all bins before fumigate if an infestation is discov loading with grain; (3) spray the walls ered. and floors of wooden bins and I n the North Central States, STORED GRAIN INSECTS 57 exposure to winter weather in most p 0 sin g 0 fin fested g ra in in fa r 01 years kills off infestations in ear corn storages before the corn reaches the stored on the farm: hence, the loss silking stagc: (3) ear Iy harvesting: (4) from insect attack is not significant if applying a protectant: (5) drying and the corn is to be used for feed during shelling: and (6) storing the corn in the ensuing season. Following mild tight bins suitable for fumigation. winters. the Angoumois grain moth Information regarding the pre may be destructive, so under such vention or reduction of grain conditions. it is well to shell corn in infestation is contained in other pub May and store it in tight bins. In the lications of the Department of Agri Southern States, field infestation can c u lt u rc , copies of which can be be reduced by: ( I) G rowing corn vari obtained from the Office of Govern eties with tight shucks that are semi mental and Public Affairs, U.S. resistant to field infestation: (2) dis- Department of Agriculture, Washington, D.C. 20250. '* u.s. GOVERNMENT PRINTING OFFICE: 1980 ()-313-822< c<>mpl.loo in 4 " hi~h in m"i,tur.,