author(s)
P Bhavana and Dr. Sasya Nagar

abstract
Repeated application of synthetic insecticides has resulted into the pest resistance and resurgence of minor pests. Thus, aroused the quest for the search of highly selective and bio-degradable pesticides to solve the problem of long-term toxicity to mammals and techniques to be developed to reduce pesticides use while maintaining crop yield. The present investigation entitled “Comparative bio efficacy of weed extracts against tomato fruit borer (Helicoverpa armigera) on tomato (Lycopersicon esculentum)” was carried out in Department of Entomology, SHUATS, Naini, Prayagraj (211007) U.P during the rabi season 2018-2019. Field studies were conducted by incorporating 10% aqueous extracts of some weeds and weed parts viz. Parthenium hysterophorus, Lantana camera, Ageratum conyzoides, Calotrophis gigantea, Argemone mexicana, Acyranthes aspera and Emamectin benzoate 5 SG. The plant extracts were found effective in reducing the percentage of infestation of target pest (Helicoverpa armigera) with the least (5.19%) in C. gigantea and highest (15.04%) in Acyranthes aspera extracts. Apart from reducing the H. armigera’s percentage infestation, weed leaf extracts also proved to yield higher cost benefit ratio, highest (1:2.38) in Calotropis leaves and lowest (1:1.51) in Acyranthes aspera. Reduced percentage infestation of H. armigera in plots treated with leaf extracts were reflected in their resultant parallel action of significantly lower fruit damage (5.19 to 15.04%) than untreated control (35%). Subsequently, the impact of reduced fruit damage by H. armigera larvae was observed in proportionate increase in fruit yield of tomato (35 to 55.60 q/ha), significantly higher than untreated control (6.6 q/ha).