PEST ON RICE
Swarming caterpillar – Spodoptera mauritia Noctuidae : Lepidoptera
- It is a serious pest on nurseries and early stage of the crops.
- During night hours, larvae cut the seedlings in large scale and present a cattle-grazing appearance to the field.
- Gregarious feeders and march from field to field.
- Damage is severe in July-September.
- It feeds on a variety of grasses
- Adult is medium sized moth, stout, dark brown with prominent triangular spot on fore wings. Eggs laid in masses on leaves and covered with grey hairs.
- Caterpillar is dark to pale green with lateral lines along the body. It pupates in earthen cocoon in soil.
Leaf folder– Cnaphalocrocis medinalis Pyraustidae: Lepidopetera
- Sporadic pest
- Chlorophyll feeders
- Young larvae feed on tender leaves without folding them.
- The older larvae fold the leaf together with a sticky substance and scrap the Chlorophyll by presenting inside the fold.
- The scraped leaves become membranous, turn white and finally wither.
- ETL: 10% damaged leaves in vegetative stage and 5% damaged leaves during flowering stage.
- The moths are golden or yellowish brown, wings have 2-3 wavy lines characterized by dark bands. Single eggs, Larva- green with a brown head, Pupation -in loose silken webs.
Skipper– Paranara mathias Hesperiidae: Lepidoptera
- Larva is pale green with constricted neck, Red ‘V’ mark on the head.
- Adult – brown coloured wings with white markings and curved antennal tip.
Caseworm– Parapoynx stagnalis Pyraustidae: Lepidoptera
- Leaves are eaten by the larvae, which remain within small cylindrical cases and are seen hanging from the plant.
- Adults are delicate white moth with pale brown wavy markings. larva – pale green with a brownish-orange head. It has filamentous gills on the sides of the body. It pupates inside the case.
Green horned caterpillar –Melanitis leda ismene Satyridae: Lepidoptera
- It is a foliage feeder. Adult is a dark brown butterfly with large wings having black and yellow eyespots on fore wings. Caterpillar is green with ridges on body and a pair of horns on the head
Yellow hairy caterpillar– Psalis pennatula Lymantriidae: Lepidoptera
- Adult moth is stout and straw-coloured with longitudinal dark band on fore wings. Larva is yellow brown with red stripes and orange head and tuft of hairs all over body. It pupates in a pale white cocoon, attached to the leaf.
Grasshoppers – Hieroglyphus banian; Oxya nitidula; Acrididae: Orthoptera
- Polyphagous pest
- Nymphs and adults feed on the leaves leaving the midribs.
- They even nibble the inflorescence
- Eggs laid in the soil. Complete their development within 3 weeks.
Whorl maggot – Hydrellia sesakii Ephydridae: Diptera
- Yellowish white longitudinal blotch on the emerging leaves. Leaves shriveled, plants stunted and maturity delayed.
- It breeds on Cynodon dactylon and Echinochloa crusgalli.
- Adult is small dull grey fly. Yellowish white Maggot feeds on the tender tissue inside the whorl.
Spiny beetle (Hispa)- Dicladispa armigera Chrysomelidae: Coleoptera
- Grubs mine into the leaf blades causing formation of white blotches, adults scrap the green matter and produce parallel whitish streaks on the leaves
- Breeds actively from May to October and hibernates during winter probably in the adult stage.
- The adult is a small bluish black beetle with numerous short spines on the body. The legless, creamy-white larvae are concealed inside the leaf tissue
Blue beetle– Altica cyanea Chrysomelidae: Coleoptera
- Steel blue beetle
- Feed on the chlorophyll
Thrips– Stenchaetothirps biformis Thripidae: Thysanoptera
- They are primary pests of nurseries and early-transplanted crops.
- Nymphs and adults lacerate tender leaves and suck oozing sap.
- Affected leaves show yellow and white streaks initially and later curl longitudinally. Terminal rolling and drying of leaves from tip to base are also seen.
- Adults are dark brown with fringed wings.
Yellow rice borer– Scirpophaga incertulus Pyraustidae: Lepidoptera
- It is a specific pest on rice.
- The plants attacked in vegetative stages result in drying of central leaf (DEAD HEART)
- The plants attacked in the ear bearing stages, produce white colour ears that are devoid of grains (WHITE EARS).
- Adults have orange yellow fore wings. The female moth has a centrally situated black spot on each of the forewings and a prominent tuft of brownish yellow hair at the tip of their abdomen. The eggs covered with the hair of the female.
- Caterpillars are dirty white, having brown head and pronotum.
- Pupate inside the stem.
Gall fly/ Gall midge– Orseolia oryzae Cecidomyiidae : Diptera
- Presence of silver shoot (onion leaf) in the place of central leaf is the typical symptom.
- Due to the feeding of maggot central leaf ultimately turns into a hollow, shiny and silvery outgrowth that is called ‘silver shoot’. The infested tillers do not bear ears.
- However, silver shoots are not expressed always in very young seedling. Instead, a swelling at the basal portion and excess tillers seen.
- Adults are mosquito like pink flies, female has a bright red abdomen. Lay eggs on the ligules of the leaf blade. Maggot is pale red, pupates at the base of the gall. Pupate at the base of the gall.
Leaf Hoppers & Plant Hoppers
Brown plant hopper Nilaparvata lugens (Delphacidae : Hemiptera)
Green leaf hopper Nephotettix nigropictus (Cicadellidae : Hemiptera)
White leaf hopper Cofana spectra
Zigzag leaf hopper Recilia dorsalis
Blue leaf hopper Zygina maculifrons
White striated plant hopper Nisia nervosa (Meenoplidae : Hemiptera )
White backed plant hopper Sogatella furcifera
Brown plant hopper –Nilaparvata lugens Delphacidae : Hemiptera
- Hopper-burn is the symptom. At early infestation, round yellow patches appear which soon turn brownish. The patches of infestation spread and cover the entire field.
- Suck the phloem sap from the stem and excrete a large amount of honeydew.
- Nymphs and adults are brown insects with large eyes. In adults Brachypterous (rudimentary wings; when plenty of food) and Macropterous (fully developed wings; when food is scarce) forms are seen.
- Transmit the grassy stunt virus disease of rice.
- ETL: One BPH/tiller or two BPH/tiller when one spider/hill presents
Green leafhopper Nephotettix nigropictus, Cicadellidae : Hemiptera
- Nymphs and the adults suck sap from the leaves, turning them yellow and ultimately brown.
- It is a green insect with black spots and markings.
- Act as vector of the diseases viz., Rice tungro virus, rice yellow & transitory yellowing.
- ETL: 60 Nos./25 sweepings in the nursery; 5 Nos./hill in the vegetative stage; 10 Nos/hill during flowering stage; and 2 Nos/hill in the tungro disease endemic areas.
Striped bug– Tetroda histeroides Pentatomidae : Hemiptera
Red spotted bug –Menida histrio Pentatomidae : Hemiptera
Black bug– Scotinophara lurida, Podopidae : Hemiptera
Mealy bug– Brevennia rehi Pseudococcidae: Hemiptera
Ear head bug–Leptocorisa acuta Coreidae : Hemiptera
Green bug– Nezara viridula Pentatomidae: Hemiptera
Tingid bug- Bako malayanus Tingidae : Hemiptera
- Nymphs and adults suck plant sap from leaf sheaths/leaves/panicles. Affected plants/ portion turn to brown or yellow followed by drying, stunted growth with reduced tillers and cause individual grain chaffy.
- Striped bug is brown with a prominent “V” shaped mark on its back.
- Red spotted bug is reddish orange comparatively small.
- Black bug is dirty black in colour with a prominent scutellum and pronotum having a spine on either side.
- Mealy bug occasionally causes heavy damage to the rice crop. Affected plants dry in circular patches (Soorai disease). The damage is particularly intense during drought conditions. They can also survive on various graminaceous weeds. Soft bodied insect and have a distinct powdery coating on their body. Nymphs and the adult females; being wingless, look alike.
- Ear head Bug sucks the sap from the ears of rice in milky stage. Affected grains become chaffy and the yield loss may be 10-40%. Black spots are seen on the grains. Adults are slender, about 20 mm long and greenish brown. They have long legs and antennae with four joints. Obnoxious odour emanates on disturbing the bugs. ETL: 5 bugs/100 panicles during flowering stage; 16 bugs/100 panicles during milky stage.
Rats Muridae: Rodentia
Mole rat Bandicota bengalensis
Bandicoot Bandicota indica
Grass rat Millardia meltada
Gerbil rat Tatera indica
Field mouse Mus booduga
- Patches of depressions in the early stages
- Cut tillers
- Cut seedlings
- Nibbled seeds and Cut ear heads
Rice Mite Oligonychus oryzae Tetranychidae : Acari
- White spots on lower surface of leaves which coalesce leading to development of white or silvery patches
- Nymph and male mite are yellowish green.
- Female is green.