ENTO-037 12/17 Cockroch Biology nd Mngement Wizzie Brown 1, Michel Merchnt 2, nd Kerry Siders 3 Cockroches re mong the most common insect pests in homes, schools, nd usinesses. They like to et mny of the sme foods we do nd re especilly troulesome wherever food is prepred or served. They lso my trnsfer disese-cusing orgnisms. Fortuntely, cockroches cn e controlled with little knowledge out their iology nd ehvior, ttention to snittion, nd effective use of commercilly ville insecticides. Identifying cockroches Cockroches hve flttened odies nd heds tht, when viewed from ove, re conceled y plte like structure clled pronotum. They move surprisingly fst with their elongted, spiny legs. Their long, thin ntenne help them find food nd feel their wy in the drk (when they re most ctive). Cockroches cn e rown, lck, tn, reddish ornge or ple green. Most hve wings, which in some species, re short nd nonfunctionl. The most common types of cockroches in Texs re the Americn cockroch, Periplnet mericn; Germn cockroch, Blttell germnic; orientl cockroch, Bltt orientlis; nd smokyrown cockroch, Periplnet fuliginos. Germn cockroches spend their lives indoors. Americn, orientl, nd smokyrown cockroches live mostly outdoors ut my move indoors in serch of food or wter. Cockroches cn infest homes when rought in with groceries or oxes, nd, once estlished, cn redily move within structures such s from prtment to prtment. Americn cockroches, lso known s wterugs or plmetto ugs, re more common in commercil uildings nd re one of the most common cockroches in sewer systems. The lrgest cockroch in Texs, it cn grow 1½ to 2 inches long. Both the dult mle nd the femle cn fly. Adults re reddish rown (Fig. 1), with tn to lightyellow nds outlining the pronotum. Young nymphs re gryish rown, ut fter the first few molts, they ecome more reddish rown (Fig. 1). Americn cockroches re long lived, reching dulthood nd sexul mturity in n verge of 600 dys. As dults, they usully live 1 to 2 yers. 1 Extension Progrm Specilist-IPM, 2 Professor nd Extension Urn Entomologist, nd 3 Professor nd Extension Agent-IPM, The Texs A&M University System Figure 1. Americn cockroch dult () nd nymph (), lso known s the plmetto ug or wterug.
outdoors, especilly in the more humid res of Texs nd other southern sttes. They prefer protected, moist, wrm sites, wy from moving ir. Common hitts re ground cover, mulch, plm fronds, soffits, eves of ttics, nd tree holes. Smokyrown cockroches rech mturity in n verge of 600 dys, nd dults typiclly live 3 to 9 months. Orientl cockroches re drk rown to lck nd grow to out 1¼ inches long. They do not fly nd their wings remin short, even s dults. The femle s wings re smller thn the mle s, which extend only slightly over hlf of the ody (Fig. 5). Nymphs re uniformly reddish rown to lck. DevelFigure 5. The dult orientl opment from egg to cockroch is nerly jet lck dult verges 575 to with short wings. (Imge from Clemson University, ugwood.org.) 600 dys nd dult orientl cockroches live 1 to 6 months. They prefer cooler, ground-level sites such s sements, crwl spces, nd wet res. Turkestn cockroches, Bltt lterlis, re ecoming more common in Texs, especilly in western prts of the stte. Mles nd femles look strikingly different (Fig. 6). The rownish yellow dult mles re 1/2 to 7/8 inch long. The pronotum hs ple mrgin, s do the upper corners of the front wings. The femle Turkestn cockroch is similr to the orientl cockroch shiny, drk reddish rown with short wings. However, the outer ses of the wings re ple like the mle Turkestn cockroch. This species is ntive to Asi ut ws introduced to Cliforni nd is expnding its rnge into Texs. It hs ecome one of the most common outdoor cockroches in El Pso, where it is found in compost, lef litter, nd potted plnts; in expnsion joints of sidewlks; nd round wter meter oxes. Figure 2. Adult () nd nymph () Germn cockroches. The dult femle in this picture crries n egg cse (oothec) tht will produce 30 to 40 smll nymphs. Germn cockroch dults re ½ to ⅝ inch long nd re light rown with two drk stripes on the pronotum (Fig. 2). Both mles nd femles hve wings extending to the end of their domens ut they do not fly. Nymphs hve wing pds nd two drk stripes extending down the entire thorx nd domen (Fig. 2). Germn cockroches re the most prolific of indoor cockroches nd cn produce genertion in out 100 dys. They re one of the most widespred insect pests to pulic helth in urn homes, prtments, nd resturnts. They trnsport germs nd re ssocited with llergies nd sthm. Germn cockroches do not live outdoors in Texs. The Asin (Blttell shini) nd field (Blttell vg) cockroches look very similr to Germn cockroches nd my e found outdoors in some res of the stte. Figure 3. Smokyrown cockroch dult () nd lrge nymph (). Smokyrown cockroches re lso lrge. Adults rech 1¼ to 1½ inches long. They re drk rown to lck nd their wings extend eyond the domen in oth sexes (Fig. 3). Their ntenne re s long s thn their odies or longer. Younger nymphs re lck with two white nds on the ody nd white-tipped ntenne (Fig. 4); older nymphs re uniformly reddish rown (Fig. 3). Figure 4. Very young smokythe smokyrown rown cockroch nymph. cockroch is common Figure 6. Mle () nd femle () dult Turkestn cockroches. (Imges y Roin McLeod.) 2
Cockroch iology Cockroches hve three-stge life cycle: egg, nymph, nd dult. Mture femles produce 12 to 36 eggs t time, depending on the species. The eggs re protected in en-shped cpsule, or oothec (oh-oh-thee-kh). The numer of oothece tht femles produce depends on the species. The femle cockroch crries the egg cpsule until it is mture or she finds secluded spot to glue it to surfce or drop it. Some femles crry it until just efore the eggs egin to htch. After htching, nymphs tend to sty in drk, protected crcks nd crevices, which they often shre with dult cockroches. At verge indoor tempertures, it tkes Germn cockroch nymph 50 to 60 dys to develop into n dult. The optimum temperture for Germn cockroches is round 80 degrees F. Wrmer tempertures shorten their development time nd increse the potentil for popultion growth. Most cockroch species re nocturnl they hide during the dy nd come out t night to look for food. For exmple, the Germn cockroch spends out 75 percent of its life in nrrow crcks nd crevices, from 1/32 to 3/16 inch wide. From these hrorges, dults emerge t night to serch for food nd wter. If you see cockroches during the dy, it usully mens there re lot of them round. They tend to congregte ner sources of het nd moisture, which ccelerte their growth nd reproductive rtes. Figure 7. Sticky crd plced within cupord for monitoring cockroches. Germn cockroch control Cockroches re est controlled through n integrted pest mngement process of inspection, snittion, exclusion, nd the use of low-toxicity insecticides. Inspect First, determine where cockroches enter the home nd where they live. The lrger types, such s Americn nd smokyrown cockroches, often enter home or usiness through poorly seled doors, roof soffits, or floor drins. If you re unsure where cockroches re entering, plce sticky crd monitors, lso clled roch hotels or glue ords, next to doors, ehind lundry pplinces, under stoves nd refrigertors, or in other loctions where cockroches my trvel or hide. Sticky crds trp cockroches nd other crwling insects (Fig. 7). They re most useful for monitoring nd less effective for controlling cockroches. Nevertheless, they cn provide some control, especilly for low numers of lrger cockroches. Figure 8. Dots showing possile sticky crd plcement for monitoring cockroches. To mke home less hospitle for cockroches, reduce clutter, keep mops nd wet items off of floors, nd eliminte food nd wter (such s empty pet owls ech night). Sticky crds (Fig. 8) plced long wlls nd cinet edges in utility rooms nd ner exterior doors help monitor cockroches nd provide some control, especilly for outdoor species. When Germn cockroches re the prolem, look for fvored hrorges or dytime hiding plces. Germn cockroches prefer crcks nd crevices in wrm loctions ner wter nd food. Look for tiny droppings deposited round cockroch hrorges. The drop- 3
pings look like crushed pepper nd stick to surfces where cockroches congregte. A good flshlight is essentil for spotting cockroches nd their signs. Use household hir dryer to flush cockroches out of hidden res. Cockroches dislike high tempertures nd moving ir nd will flee when hot ir is directed into hrorge. Once you identify hrorges, tret or sel them to prevent further use. Remove food, wter, nd hrorge Good clenup nd snittion prctices re essentil to effective cockroch control. When food or wter is scrce, cockroches must serch frther ech night to survive. Good snittion puts stress on cockroch popultions nd increses the effectiveness of its nd other insecticides. Clen the floors nd counters nd fix wter leks to remove moisture sources. Sel crcks nd crevices where cockroches hide or enter uildings. Use good-qulity culk or selnt to close the gps round sinks nd pluming, in wlls, nd long kitchen splsh gurds. Control indoor cockroches sfely Trps lone do not provide sufficient control of wellestlished cockroch infesttions. For them, you will need to use vcuum clener, it, dust, or spry. Vcuums. Vcuum cleners cn e useful in removing oth cockroches nd their food sources under stoves nd ehind refrigertors. In ddition to removing cockroches, vcuum clener helps remove crums nd other food tht cockroches depend on. Mke sure the vcuum hs HEPA filter tht cn filter out the finest dust prticles ecuse cockroch hrorges often contin llergens tht cn cuse sthm or mke rething difficult for some people. Bits. A food mixed with n insecticide, its re mong the most effective insecticides for controlling cockroches in homes. Cockroches feed on the it nd return to their hiding plces to die. Bits re most effective when few food lterntives re ville. The most common consumer it formultions come in redy-to-use plstic it sttions or tues contining gel its. When using preited continers, lwys use enough sttions to effectively tret infested rooms t lest one it sttion within 1 to 2 feet of every suspected cockroch hrorge. Follow the pckge directions. Plce the it sttions ner grge cns, under sinks, long cinet edges, ner crcks, in corners, or under dishwshers, refrigertors, or stoves (Fig. 9). Plce them horizontlly or glued to verticl loction, (Fig. 10). When using gel its, it is more effective to use mny smll plcements (idelly, no lrger thn pesized) thn few lrge ones. Avoid over-ppliction of the it so it is not esily seen nd does not drip from the ppliction site. Figure 9. Plcing cockroch it sttion under stove. Sttions re most effective if plced long wll or cinet edge. Exmine the its regulrly nd replenish them s needed to keep them fresh nd in supply for the cockroches to et. Bits work most effectively when cockroches cn feed freely nd return to their hrorges to die. Remove old, dried-up it y removing the it sttion or scrping off the it with putty knife. Avoid pplying other pesticides such s dusts or sprys close to it sttions ecuse cockroches will void contminted its. If it does not control the cockroch popultion within 2 to 3 weeks, try different it with new ctive ingredient. Switch ctive ingredients regulrly to void creting resistnt cockroch popultions. Dusts. Some insecticides re sold in dust form tht cn e pplied into wll voids tht re difficult to tret with other forms of insecticides. Dusts lso cn e trnsferred esily from one treted insect to nother during contct in hrorge res. Effective dusts for cockroch control include some plnt-sed insecticides nd oric cid, which remins Figure 10. Plce its in crcks nd crevices where cockroches hide. Mny smll, pe-sized plcements re more effective thn fewer, lrger ones. 4
If you use sprys or ug oms, follow the directions crefully nd remove or cover ll dishes, cookwre, nd utensils. Over-ppliction of ny pesticide is not only ineffective, ut cn e dngerous to you nd your fmily. Figure 11. Applying dust to wll void where pluming pipes enter the wll. one of the more effective cockroch control insecticides, especilly when used properly. Do not pply oric cid or other dusts in the open or on countertops or shelves where they cn contminte surfces contcted y dishes, food continers, people, or utensils. Good sites for using dusts include voids round pluming (Fig. 11); under the dishwsher, refrigertor, nd stove; nd in crcks nd crevices where its cnnot e pplied. Dusts re most effective when pplied lightly so tht the residues re rely visile. Cockroches will void hevy dust deposits. The est wy to pply dusts is to shke the continer with the lid or cp on, remove the lid, nd puff the dust lightly into the void spce. Applying dusts with spoon is ineffective nd will lwys use too much insecticide. Use dmp cloth to immeditely clen up ny visile residues fter dust ppliction. Totl-relese erosols nd sprys. While efficient for killing flying insects nd insects on exposed surfces, totl-relese erosols (ug oms) generlly do not eliminte cockroches ecuse they do not penetrte the crcks where most cockroches hide. Likewise, insecticide sprys re not nerly s effective s its re for eliminting Germn cockroch infesttions. Controlling other cockroches outdoors Americn, orientl, nd smokyrown cockroches re usully found outdoors nd in nonfood res of homes nd commercil uildings. They ecome pests when they enter home or usiness. If you re unsure where cockroches re getting in, use sticky crd monitors. Outdoors, look for drk, moist res close to decying orgnic food sources. Cockroches cn live in compost piles, ground cover plnts, hollow trees, mulch, old stumps, plm fronds, woodpiles, sewer mnholes, nd underground wter meters. Americn nd orientl cockroches use floor drins s common points of entry into uildings. To minimize this risk, keep P-trps filled with wter to crete rrier etween the sewer nd the home or usiness. Check the threshold sels under doors nd ensure tht roof soffits re screened to keep cockroches outdoors. Bits Grnulr its for cricket nd cockroch control work well, especilly outdoors in ground covers nd mulched plnt eds. Lightly sprinkle the it ccording to the lel directions. Avoid pplying visile mounds of it tht might ttrct dogs or cts. Continerized it sttions re ville for lrge cockroches. Plce the sttions ginst wlls, especilly round doors nd other suspected entry points. Insecticide sprys cn lso help mnge outdoor cockroches or tret them in grges nd home utility res. Spry suspected cockroch hrorges nd entry points such s uilding perimeters, doors, soffits, nd wter oxes. In grges nd utility rooms, spry the room edges nd plces tht re unlikely to e contcted y children or pets. 5
Tips for professionls Vry the type of insecticides used ginst Germn cockroches. Rotting oth its nd sprys 1 or 2 times yer reduces the risk of insecticide resistnce, especilly in prtments tht re treted regulrly for cockroches. When rotting insecticides, switch etween insecticides with different modes of ction. See http://www.irc-online.org/tems/mode-of-ction/ for more informtion out insecticide resistnce mngement. Pyrethroid insecticides re highly repellent to Germn cockroches. Using its nd nonrepellent insecticides such s chlorfenpyr or oric cid my improve control in difficult cses. Alwys crry clen rg nd putty knife for clening up old it residues nd oversprys from liquid or dust pplictions. A good monitoring progrm cn help you identify res of cockroch ctivity s well s document the effectiveness of your control progrm. Recording the numer of cockroches in trps cn e time consuming, ut my e useful, especilly in sensitive ccounts or ones with mny cockroches. The informtion given herein is for eductionl purposes only. Reference to commercil products or trde nmes is mde with the understnding tht no discrimintion is intended nd no endorsement y the Texs A&M AgriLife Extension Service is implied. Texs A&M AgriLife Extension Service AgriLifeExtension.tmu.edu More Extension pulictions cn e found t AgriLifeBookstore.org Texs A&M AgriLife Extension provides equl opportunities in its progrms nd employment to ll persons, regrdless of rce, color, sex, religion, ntionl origin, disility, ge, genetic informtion, vetern sttus, sexul orienttion, or gender identity. The Texs A&M University System, U.S. Deprtment of Agriculture, nd the County Commissioners Courts of Texs Cooperting. Revision 6