Abstract
The old world date mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae) is a severe spider mite pest of date palm in most of the Middle East and North Africa. Considering that nothing is known about the performance of phytoseiid predators against O. afrasiaticus, biology, predation, and life table parameters of Cydnoseius negevi (Swirski and Amitai) and Neoseiulus barkeri Hughes (Acari: Phytoseiidae), collected from date palm orchards, were studied under laboratory conditions (25, 35(degrees)C and 35 +/- 10% RH) as a first step to understand their effectiveness against all mobile life stages of O. afrasiaticus. For both predators, oviposition period was significantly shorter at 35(degrees)C than at 25(degrees)C. The following parameters were obtained for C. negevi and N. barkeri at 25 and 35(degrees)C, respectively: female longevity, 31.8, 20.1, 35.7, 27.4 d; fecundity, 21.6, 38.0, 18.8, 34.8 eggs per female; oviposition period, 23.9, 13.7, 25.9, 18.1 d. Total predation of C. negevi and N. barkeri female was 246.0, 270.0, 227.6, 205.3 prey at 25 and 35(degrees)C, respectively. Rectal plugs were observed attached to the opisthosoma of some adult females of N. barkeri, which often cause the mite to stick to the surface. Life table parameters were estimated as net reproductive rate (R-0) 10.44, 17.35, 10.19, 13.84, intrinsic rate of increase (r(m)) 0.14, 0.19, 0.13, 0.16 d(-1), finite rate of increase (lambda) 1.15, 1.21, 1.12, 1.17 d(-1), generation time (T) 17.03, 15.17, 17.83, 16.61 d, doubling time (DT) 04.95, 03.64, 05.33, 04.33 d for C. negevi and N. barkeri at 25 and 35(degrees)C, respectively. The values of intrinsic rate of increase and net reproductive rate were higher in C. negevi than N. barkeri at both temperature regimes. Therefore, it could be concluded that C. negevi performance was better than N. barkeri against O. afrasiaticus and can be considered as a valuable addition to the existing methods for spider mites control.