BP Singh

178 Shashi Bhallatunnel into the dead wood and construct irregular and extensivegalleries inside the stem of arecanut. The caterpillars, Atherastiscirculata and Ptochoryctes rosaria, build their galleries on the trunkand branches of rubber plant filling them with feacal matter andsilk. They feed on the dead bark inside and create irregular,depre:?sed channels into stems. This interferes with latexcollection. The bark beetles, Scolytus rugulosus and Phloeotribusliminaries attack the trunk and branches of the peach tree. Galleriesof borers are found in the inner bark radiating from the main orparent gallery and terminating in sman, round exit holes throughthe bark.Root feedersThere are a number of insects which are found in the §.oil andlive by feeding on the r.99ts of plants and lrees by ch~wing, ~9ring,sy_(;}gng or fQrming galls, thus causing loss of water and nutrientabsorbing tissues. These prevent proper establishment andgrowth. These insects may include cti9s,ets, t&nnites, ~bi~~ grt,lbs,several b~es and vx~ey:ils. Though the damage caused to rootmay vary depending on the portion of root infested. Generallythe attacked plants show Shm!iPg, discoiouration, withering andin severe infe.s!£pon, death of the J?lant. The larvae may feedexternally on roots as in wireworms, weevils, grubs and whitegrubs. Grubs bore or tunnel into the root as Longitarsusbelgaumensis on sunhernp plants. Root. aphid, Tetraneuranigriabdominalis suck the sap from the roots. The woolly aphid,Eriosoma lanigera spends its life cycle in the soil and both adultsand nymphs suck the sap from the roots of apple causing theformation of root galls. The rhizome weevil, Cosmopolites sordidus,grubs bore into banana rhizome and cause death of the plant.Tuber feedersTubers are also attacked by insects. v.y:ireYY,Qrms bore thetubers by making ~els. Potato tuber moth larvae boredown the stem into the tubers by making the tunnels where rottingoccurs due to secondary infection. The tubers of sweet potato areriddled with holes by the larvae of weevil Cylas formicarius. Bothlarvae and adults of yarn beetle bore the yam tubers with widetunnels. These weevils remove the stored food from tubers andcorms and affect next season's growth.