SHARMA, P LNIDHI2023-06-122023-06-122023-04https://krishikosh.egranth.ac.in/handle/1/5810197574ABSTRACT The present study entitled “Effect of host plants and pesticides on the performance of Neoseiulus longispinosus (Evans) against Tetranychus urticae Koch” was conducted during the year 2019-2022 in the Department of Entomology, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni, Solan, Himachal Pradesh. The predatory potential of N. longispinosus was evaluated on five host plants with and without the effect of recommended insecticides. The biology and demographic parameters were highest on bean followed by cucumber and the least on tomato and brinjal. The highest fecundity of the predatory mite was observed when T. urticae protonymphs were provided as prey on bean leaves (48.78 eggs/ female), followed by eggs (48.3 eggs/ female) and deutonymph (41.12 eggs/ female). The feeding potential of predatory mite was higher on prey eggs than proto- and deutonymphs. During the lifetime highest feeding was recorded for adult female predatory mite against prey egg on bean, brinjal, cucumber, okra and tomato were 139.50, 37.22, 62.90, 50.78 and 31.63 eggs, respectively. The predatory mite exhibited a type II functional response to all stage of prey mite on each tested host plant with or without the influence of insecticides. Mutual interference was observed when the number of foraging predators per arena increased from 2 to 8; as a result, more prey was consumed overall, but per-capita predation rate and searching efficiency declined with the increase in predator density. Among evaluated insecticides, thiacloprid, thiamethoxam and lambda-cyhalothrin reduced the predatory potential of N. longispinosus. The release rate of predatory mite, N. longispinosus, was found to be effective against T. urticae when released twice at predator: prey ratio of 1:7.5. Among host plants, bean proved to be better than the other tested hosts to raise T. urticae for mass production of N. longispinosus. Overall, N. longispinosus is a promising biocontrol agent of T. urticae, and can be integrated with insecticides like, chlorantranilirole on the day of application. However, a gap of 3-5 days is required between the application of the other tested insecticides and the predator release.EnglishThesis