Life Table Parameters and Consumption Rate of Cydnodromus picanus Ragusa, Amblyseius graminis Chant, and Galendromus occidentalis (Nesbitt) on Avocado Red Mite Oligonychus yothersi (McGregor) (Acari: Phytoseiidae, Tetranychidae)

Abstract

The avocado red mite Oligonychus yothersi (McGregor) is the major leaf pest in Chile's avocado orchards. It affects leaf physiology and makes it necessary to seek new natural enemies to interact with low population densities of O. yothersi. The potentiality of three predator mites: Cydnodromus picanus Ragusa, Amblyseius graminis Chant, and Galendromus occidentalis (Nesbitt) was evaluated under laboratory conditions (27 +/- 1.93 C, 87 +/- 3.61\% H. R. and 16: 8 (L: D) photoperiod) on avocado leaf disks Persea americana Mill. var. Hass (empty set = 5 cm) by separately feeding eggs, immature, and adult females of O. yothersi, and registering postembryonic development, consumption, as well as life table parameters. The postembryonic development of C. picanus was significantly lower (5.46 days) compared to both A. graminis (7.33 days) and G. occidentalis (8.69 days) which were fed with immature O. yothersi. The life table parameters of C. picanus were net reproductive rate R-0 = 25.41, finite rate of increase lambda = 1.29, and mean generation time T = 12.46. The net intrinsic rate of increase (r(m)) was significantly higher for C. picanus (r(m) = 0.25) in contrast with G. occidentalis (r(m) = 0.19), while A. graminis showed r(m) = -0.06 indicating that its population didn't have descendants. Under laboratory conditions, rm registered by C. picanus is an indicator of its predatory potential to control O. yothersi. It can be assumed that the pest population reduction pattern could be maintained under field conditions.