IPM Packages for Crops

insect pests

INSECT PESTS

Stem borers [(yellow stemborer ( Scirpophaga incertu- las ), white stemborer ( Scirpophaga innota- ta ), striped stemborer ( Chilo polychrysus ), dark-headed stemborer ( Chilo suppressalis ) (Lepidoptera: Crambidae); pink stemborer ( Sesamia inferens ) (Lepidoptera: Noctuidae)] Damage caused by these stem-boring species is similar. Early instars do not cause severe damage when they feed on leaves and within leaf sheaths. However, when caterpillars feed within the culm on growing point and vascular tissue, they cut off the growing portion of the plant from the base. At the vegetative stage of plant development, feeding of larvae results in plants failing to produce panicles (dead hearts). Even after damage, rice is capa- ble of partly or fully compensating for losses of tillers by putting forth additional tillers. Several native predators, parasitoids (braconid, eulophid, mymarid, scelion- id, chalcid, pteromalid, trichogrammatid wasps, ants, lady beetles, staphylinid bee- tles, gryllid, green meadow grasshopper, and mirid, phorid and platystomatid flies, carabid and lady bird beetles, chloropid fly, gerrid and pentatomid bugs, ants, and mites, earwigs, birds, asilid fly, dragonflies, damselflies, and spiders) and entomopatho - gens ( Steinernema carpocapsae, Heter- orhabditis bacteriophora, Metarhizium anisopliae and Beauveria bassiana ) are known to manage stemborers.

Rice gall midge [ (Orseolia oryzae) (Diptera: Cecidomyii- dae)] Infestation leads to silver shoot or induc- tion of gall, which causes an onion leaf appearance. Newly hatched grey-white maggots move between the leaf sheath and the stem and approach the opening point of the apical or side bud at a node. Next, the maggot feeds inside the developing bud, which is a zone of differentiation for new tillers. A hollow chamber (gall) formation happens around the maggot and as the maggot feeds, gall enlarges at base and elongates. Instead of development of pan- icle, gall development occurs. Crop loss is ranges from 10-100 percent. Predatory mite Amblyseius imbricatus (Parasiti- formes) attacks eggs. Maggot parasitoids Platygaster oryzae and Obtusiclava oryzae (Hymenoptera) and pupal parasit- oids, Neanastatus oryzae and N. cinctiventris (Hymenoptera) are known. Brown planthopper [ Nilaparvata lugens (Homoptera: Delpha- cidae)] This pest is polyphagous and distributed throughout Asia. The weed Leersia hexan- dra functions as a primary alternate host. It infests all stages of plant growth. Both nymphs and adults of this pest damage rice plants by sucking sap and removing trans- locating nutrients, hence, reducing net photosynthesis. At early infestation, round yellow patches appear, which soon turn brownish on the plants. This condition is called ‘hopperburn.’ Feeding and egg-lay - ing sites expose plants to fungal and bacte - rial infections. Honeydew excreted by the nymphs and adults at the base of the plants induce growth of sooty mold. Nilaparvata lugens also transmits the virus diseases, such as Rice ragged stuntvirus (RRSV) and Rice grassy stunt virus (RGSV). Increased nitrogen fertilizer use has been suggested to benefit N. lugens’s population growth.

Rice mealybug [ Brevennia rehi (Hemiptera: Pseudococci- dae)] This pest is a foliar feeder on rice in Asia. Severe drought, bad drainage, and poor soil increase infestation. Presence of alternate hosts in fields or on field bunds, presence of ants, and irrigation water helps migration of the bug. Nymphs and adults suck sap from the rice stem, which results in smaller leaves, yellowing, abnormal tillering, and stunted plants. When heavily infested, either no panicles are formed, or they do not fully emerge from the boot and may dry off. Lady beetles Coccinella repanda, Menochilus sexmaculatus , and Harmonia octomaculata (Coleoptera); parasitoids Cerapkron sp., Adelencyrtus sp., Cheiloneurus sp., Doliphocerus sp., Gyranusa sp., Mayeridia sp., Parasyrpho- phagus sp., Xanthoencyrtus sp., Aprostoce- tus sp., Chrysocharis sp., Desostenus sp., Tetrastichus sp., Lymaemon sp., Callitula sp. Diparini sp., and Thysanus sp. (Hyme- noptera); Anatrichus pygrnaeus and Mepa- chymerus ensifer (Diptera) are reported to attack this mealybug.

Rice gall midge damage