FUNCTIONAL RESPONSE AND EVALUATION OF Neoseiulus californicus AS BIOLOGICAL CONTROL AGENT OF Tetranychus urticae

Abstract

The research work was conducted in the laboratory of the Department of Entomology, Hajee Mohammad Danesh Science and Technology University (HSTU), Dinajpur during May to December 2023. The functional response of Neoseiulus californicus (Mesostigma: Phytoseiidae) to five densities of TSSM Tetranychus urticae (Trombidiformes: Tetranychidae) was investigated in the laboratory conditions. The research work was carried out on leaf disc in petridishes with 5 replications. The rate of searching efficiency and handling time of predator were estimated as 0.588 d-1 and 0.0052 min for egg, 0.593 d-1 and 0.0052 min for larva, 0.626 d-1 and 0.0197 min for protonymph, 0.0504 d-1 and 0.0283 min for deutonymph. The handling time increased as the prey progressed to the next stage. The model forecasts a maximum prey consumption on egg and larval stages were 192.30 while minimum on deutonymph 35.33 based on the functional response. Biological control of two spotted spider mite by N. californicus was also conducted in the potted bean plants. Four treatments were setup with a control group (no release of predator) and each treatment were replicated with five times. The effectiveness of the predatory mite, N. californicus, as a suppressive agent of the two spotted spider mite was evaluated at predator: prey ratio of 1:10, 2:10, 3:10, 4:10 and a control group. At ratios 4:10 N. californicus significantly reduced T. urticae population about 85.63% and 1:10 ratio shown the lowest reduction of prey populations 72.09% one week after release of predator. The average motiles number of predator were found maximum on T4 (0.78) and minimum in T1 (0.04). N. californicus significantly reduced TSSM in treatments with high predator: prey ratio. All treatments significantly reduced TSSM compared with the control groups (no releases). Results indicated that release of N. californicus is able to sustained control of TSSM populations.