Leaf miner (phytomyza spp.) infestation on som plant (machilus bombycina king) and plant based formulation for their sustainable management

Abstract

Muga silk worm (Antheraea assama West wood) is reared on leaves of som plant (Machilus bombycina King) because of their high nutritional value. Rearing becomes difficult due to attack of large number of insect-pests on som plant. Leaf miner (Phytomyza spp.) (Diptera: Agromyzidae) is a major pest and very harmful to som plant leaves. From observation it is found that leaf miner was found active throughout the year on som plant leaves. Higher population level was maintained during 27th standard week to 34th standard week that is during 1st week of July to last week of August with highest population (20.42 larvae/5 leaves) recorded on 32nd standard week that is on the 2nd week of August. Leaf miner population had a significant positive correlation with temperature and relative humidity. A mixed formulation of imidacloprid with azadiraction was found to be the most effective against leaf miner showing 79.24% mortality with imidacloprid 76.25% and in the mixed formulation imidacloprid+polygonum 73.74 %. It is concluded that lower dose of imidacloprid mixing with azadiractin/polygonam/spilanthes extracts will be environmentally sound and eco-friendly and is recommended for leaf miner control to promote organic farming.