Management of gall midge (Orseolia oryzae Wood Mason) through plant nutrients supplied through organic and inorganic sources with emphasis on neem and karanj cakes

Abstract

Rice (Oryza sativa L.) is the most important food crop of India including the state of Jharkhand. Among the half of a dozen of major insect pests of rice prevailing in the state, gall midge (Orseolia oryzae W.M.) is one of them. Due to feeding by the maggot of the insect on the growing point (of central leaf sheath) of rice plant, silver shoot (SS) is produced, resulting failure of emergence of panicle in the affected tiller, which causes direct yield loss. The present experiment was conducted for two consecutive years, 2013 and 2014 in wet season with the sole objectives for management of gall midge through use of organic and inorganic form of plant nutrients and their appropriate and balanced combination in right quantity. The overall results of the two years experimentation revealed that neem cake @ 2.5 t ha-1 proved to be the most effective in minimizing the incidence of gall midge (incidence 0.75% SS). Result of karanj cake @ 2.5 t ha-1 remained at par (incidence 1.42% SS). It was interesting to note that neem and karanj cake applied @ 0.5 to 2.5 t ha-1 were superior over the other treatments in reducing the pest incidence. The highest incidence of gall midge (10.78% SS) was recorded in case of rice plants receiving sole application of nitrogen @ 80 kg ha-1 supplied through urea. It was almost at par with rice plants receiving all the three N, P, K @ 80, 40 and 20 kg ha-1 respectively (RDF) (silver shoot incidence of 9.78%). The highest yield (41.50 q ha-1) was obtained in treatment i.e. sole use of neem cake @ 2.5 t ha-1, which was at par with sole use of karanj cake applied @ 2.5 t ha-1 (38.60 q ha-1). Even the minimum dose of neem and karanj cake (@ 0.5 t ha-1), each separately applied, with supplementary application of N, P, K) could be able to reduce the silver shoot incidence upto appreciably lower level and higher grain yields of 35.90 and 34.20 q ha-1, respectively. The, rice plant receiving sole nitrogen @ 80 kg ha-1 through urea had lowest grain yield of rice (22.40 q ha-1).