Life history of the predatory mites Amblyseius swirskii and Neoseiulus cucumeris (Acari: Phytoseiidae), candidates for biological control of the date palm mite, Oligonychus afrasiaticus (Acari: Tetranychidae)

Abstract

The date palm mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae), is a serious pest of dates in the Middle East and North Africa, inflicting severe economic damage if not controlled. As predaceous mites are known as potential biocontrol agents against several pests, predation capacity, life table, reproduction and survival of Amblyseius swirskii Athias-Henriot and Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae), collected from date palm farms, were studied in a laboratory setting (25, 30, 35°C and 50 ± 5% RH) against all motile stages of O. afrasiaticus. For both predators, mean developmental time, oviposition period and longevity were inversely related to temperature from 25 to 35°C. The following parameters were obtained for A. swirskii and N. cucumeris at 25, 30 and 35°C, respectively: Female developmental time, 9.37, 7.29, 5.56, 10.67, 8.38, 6.45 d; oviposition period, 19.77, 16.18, 13.94, 15.90,13.84,10.64 d; longevity, 29.39, 24.79, 20.64, 25.42, 21.94, 17.39 d; fecundity, 31.91, 37.10, 42.16, 21.75, 26.84, 30.56 eggs per female. For both predators, the maximum daily predation rate was recorded at 35°C and occurred during the oviposition period. Total predation of A. swirskii and N. cucumeris female was 370.86, 387.54, 405.83, 232.14, 263.32, 248.85 prey at 25, 30 and 35°C, respectively. The maximum reproduction rate of A. swirskii and N. cucumeris (3.02, 2.87 eggs/♀/day) was recorded at 35°C while the minimum one (2.00, 1.36 eggs/♀/day,) was recorded at 25°C. Life table parameters were estimated as net reproductive rate (Ro) 21.68, 25.94, 29.52,18.95, 20.25, 22.78, Mean generation time (T) 24.92, 21.82, 18.24, 26.30, 23.60, 20.56 d, intrinsic rate of increase (rm) 0.181, 0.232, 0.248, 0.170, 0.185, 0.196, finite rate of increase (λ) 1.365, 1.551, 1.706, 1.126, 1.324, 1.428 for A. swirskii and N. cucumeris at 25, 30 and 35°C, respectively. The results of this study suggested that the two phytoseiid species are promising biological control agents of O. afrasiaticus at a wide range of temperatures.