Ecology, Environment and Conservation Paper

INVESTIGATION ON INFECTIVITY OF STEINERNEMA CARPOCAPSAE RECOVERED FROM DIFFERENT HOSTS AGAINST SPODOPTERA LITURA INFECTING GREEN GRAM

S.S. Bhati, A.U. Siddiqui and B.S. Chandrawat

Abstract

Green gram (Vigna radiata) also known as moong bean, is most important legume crop grown by farmers since millennia providing nutritionally balanced food to the people. Green gram is an important source ofeasily digestible high quality protein for vegetarians. It contains 24 per cent protein, 0.326 per cent phosphorus, 0.0073 percent iron, 0.00039 per cent carotene, 0.0021 per cent of niacin. The green gram is attacked by number of insect pests but Spodoptera litura is more serious pest. Realizing the role of these pests as limiting factor in agricultural productivity, several methods were developed and incorporated in to management program of the economically important pest. Use of insecticides although found effective however, looking into the adverse effect of chemical insecticides, several bioagents have been tried time to time to manage this pest but none of them could give desirable results. The uses of entomopathogenic nematodes as a biological control agent of insect pests are more effective. In general EPNs are environmentally more suitable than the latter and, although currently more expensive in monetary terms are in the long run less expensive in terms of deleterious side effects such as human health hazards and destruction of nontarget organism. The fact that many of these organisms being at low densities also makes them more attractive to use than conventional insecticides. Entomopathogenic nematodes have been found effective for the management of tobacco caterpillar and are used as bio insecticides against a number of lepidopteran pests. Infectivity of entomopathogenic nematode, Steinernema carpocapsae against tobacco caterpillar was studied in pot conditions on greengram and observation was recorded after every day up to 10 days with different inoculum levels viz., 10000, 15000 and 20000 IJs/plant of S. carpocapsae. carpocapsae produced on natural hosts.The experimental results revealed that maximum (82.50) per cent mortality of S. litura was observed at 20000 IJs of S. carpocapsae recovered from S. litura after 9th days followed by 80.00 per cent mortality at 20,000 IJs recovered from C. cephalonica, G. mellonella and H. armigera. While, minimum 72.50 per cent mortality was recorded at 10,000 IJs recovered from H armigera. Therefore, it was concluded that the mortality of insect larvae increased with an increase in the inoculum levels and period of exposure.