Field evaluation of botanicals and fish oil rosin soap against major pests of medicinal coleus.

摘要

A field experiment was conducted at Agricultural College and Research Institute, Madurai during June-November 2009 to evaluate the field efficacy of botanicals and fish oil rosin soap for the management of major pests of coleus (Coleus forskohlii Briq.). Ten rounds of application of six botanicals and one animal origin insecticide at fortnightly interval were made and the incidence of thrips (Scirtothrips dorsalis Hood), scale insects (Orthezia insignis Browne) and defoliator (Orphanostigma abruptalis Wlk.) on coleus were recorded. Azadirachtin 0.15% EC (Neem Gold) (1.5 ml/lit.) was effective in reducing the incidence of thrips and defoliator, recording the mean leaf damage of 6.1 per cent for thrips and 6.6 per cent for defoliator. Fish oil rosin soap (FORS) (25 g/lit.) was effective against scale insects of coleus and recorded the lowest mean leaf damage of 4.8 per cent. Azadirachtin recorded the highest yield of 20,836 kg of wet tubers/ha whereas untreated control recorded only 12,451 kg wet tubers/ha.