Status of mole cricket, Gryllotalpa sp., as a pest of barley seed and seedlings together with its control

Field and laboratory trials were conducted to study the barley seed and seedling damage by mole cricket, Gryllotalpa sp. Pest activity was observed only in those areas where soil remained wet throughout the year as a result of high water table. On an average, 2.67 crickets were found/m² area up to a depth of 25 cm. The crickets damaged the barley seeds to varying extent, viz., in variety hulled DL 70, 33.67% and hulless IB 65, 28.34% in the field. In the laboratory, it was respectively 30.0% and 50.0%. Seeds were either completely or partly eaten and showed typical chewed symptoms. Dry and hard seeds, were not eaten. Only those becoming soft after absorbing water were attacked. Also, seedlings were gnawed just below the soil suface which came off with the slightest pull. The first visible symptom was the wilting of younger seedlings which became yellowish in colour and ultimately dried. In older seedlings, typical fibrous cuts were found at the base of shoot just below (1 cm) the soil surface. Sometimes, shoots remained attached with roots by a few strands which led to ‘dead-heart’ formation. Seedling mortality varying from 9.89 to 12.84/plot led to gaps in plant stand. Among the various insecticides, viz., carbofuran, isofenphos, aldrin 30 EC and 5% dust evaluated as seed treatment for its control, carbofuran 1% was the best. Isofenphos adversely affected the seed germination, and was phytotoxic to seedlings. Soil application of BHC 10% and aldrin 5% dusts @ 25 kg/ha were ineffective. Among the various granular insecticides, viz., phorate 10 G, carbofuran 3 G, disulfoton 5 G, aldicarb 10 G, carbaryl 4G, quinalphos 5G, mephospholan 5 G and fensulfothion 5 G, only carbofuran 3 G and phorate 10 G used @ 1.50 kg a.i./ha in seed furrow at the time of sowing were most effective.