SUITABILITY OF MASS MULTIPLICATION OF Trichogramma ON EGGS OF ERI SILKWORM Philosamia ricini

Abstract

newline The present investigation titled, SUITABILITY OF MASS MULTIPLICATION OFTrichogrammaON EGGS OF ERI SILKWORM, Philosamiaricini, was undertaken to explore a novel, sustainable, and value-added approach for augmentative biological control by leveraging the underutilized resources of the sericulture industry. Recognizing the limitations associated with the conventional host Corcyra cephalonica, the study systematically evaluated the biological and functional potential of Philosamiaricini (eri silkworm) eggs as an alternative and superior host for the mass multiplication of three Trichogramma species viz., T. chilonis, T. japonicum, and T. embryophagum across four major objectives: host preference, host egg age suitability, functional response and optimization of host:parasitoid ratio of T. embryophagum at different exposure levels. In host choice tests, although all three species initially preferred C. cephalonica in the initial generations, P. ricini eggs demonstrated significantly superior suitability for parasitoid development. T. embryophagum achieved the highest biological performance on eri eggs in dual-choice test, with adult emergence of 8.20±and#8239;0.20 adults/egg, female emergence percentage of 66.51±0.22 per cent and adult longevity of 8.60and#8239;±and#8239;0.40 days compared to only 1.00and#8239;±and#8239;0.00 adults/egg, 56.92±0.35 per cent female emergence, and 5.20and#8239;±and#8239;0.70 days on Corcyra. Host egg age trials revealed that P. ricini eggs retained parasitism potential up to 52 days, with T. embryophagum recording 70.00and#8239;±and#8239;1.64 per cent parasitism on 16-day-old eggs and 02.22±1.71 per cent even at 52 days followed by T. chiloniswith 67.40±1.60 per cent parasitism on 1-day-old and 1.81±1.84 per cent on 52-day-old eggs. In contrast, all species showed a rapid decline in parasitism on Corcyra beyond 10 12-day- old eggs. Adult emergence from aged eri eggs also remained higher (T. embryophagum: 65.77and#8239;±1.30 per cent on 16-day-old eggs). Functional response analysis confirmed a Type II response across species, with T. embryophagum de