A LIFE TABLE ANALYSIS TO EVALUATE BIOLOGICAL CONTROL OF FOUR MITE SPECIES ASSOCIATED WITH OLIVE TREES USING THE PREDATORY MITE Phytoseius plumifer (ACARI: PHYTOSEIIDAE) IN SAUDI ARABIA.

The predatory phytoseiid mite, Phytoseius plumifer (Canestrini & Fanzago) (Acari: Phytoseiidae), has shown promising traits for biological control of four mite species, Aceria olivi, Oxycenus niloticus, Tegolophus hassani (Acari: Eriophyidae) and Tetranychus urticae (Acari: Tetranychidae), the major pests of olive trees in Saudi Arabia. In the present study, reproduction and population growth parameters of P. plumifer on moving stages of four mite species were studied in the laboratory at 35±1°C, 55±5% RH and a photoperiod of 12: 12 (L: D) hours. The predatory mite, P. plumifer demonstrated that it is capable of developing successfully from egg to adult stage throughout its entire life history consuming only four preys. The total immature developmental time was 5.67, 5.87, 5.92 and 5.77 days for females and 5.18, 5.32, 5.49 and 5.50 days for males when the predator consumed A. olivi, O. niloticus, T. hassani and T. urticae, respectively. The sex ratio of P. plumifer was 0.73, 0.70, 0.70 and 0.60 (females/females + males). Mated females laid on average 2.83, 2.70, 2.38 and 1.72 eggs per day and 57.46, 50.80, 50.02 and 33.95 eggs during their mean ovipositional period of 20.25,18.77, 20.95 and 20.88 days, respectively. The net reproductive rate (R0) was 37.65, 35.18, 33.59 and 26.38 females/female/generation, the intrinsic rate of increase (rm) was 0.298, 0.288, 0.277 and 0.179 females/female/day, the finite rate of increase (λ) was 1.937, 1.861, 1.785 and 1.212 population multiplication/day, and the mean generation time (T) was 14.25, 15.78, 15.22 and 16.56 days when a predator consumed A. olivi, O. niloticus, T. hassani and T. urticae, respectively. The adult predatory female consumed an average of 110.66 A. olivi, 103.71 O. niloticus, 99.75 T. hassani and 14.35 T. urticae/day. These findings imply that the four mites, especially A. olivi, proved to be acceptable nourishment for P. plumifer, as a facultative predator, where P. plumifer does well and is widely and successfully used for biocontrol of A. olivi, O. niloticus, T. hassani and T. urticae associated with olive trees. [ABSTRACT FROM AUTHOR]