Efficiency of Orius minutus for control of Tetranychus urticae on selected potato cultivars

Abstract

The influence of host plant traits of five potato cultivars: Savalan, Agria, Morene, Kondor and Diamant on the population density of two-spotted spider mite (TSM) Tetranychus urticae Koch, and ovipositional preference, predation rate and life history parameters of its predator Orius minutus L. were studied under laboratory conditions (23 ± 1°C, 50 ± 5% RH and 14L:10D). The density of TSM adults on Savalan, Agria and Morene was significantly lower than on Kondor and Diamant. In both no-choice and free-choice experiments, the females of the predator laid more eggs on TSM-infested leaves of Savalan (6 eggs/leaf and 24 eggs/plant) than on Agria, Morene, Kondor and Diamant. In predation rate experiments, the females of O. minutus consumed more TSM on the infested leaves of Savalan (32 TSM/predator during 48 hours) than on Agria, Morene, Kondor and Diamant. In performance experiments, the predator nymphs developed faster when reared on TSM-infested leaves of Savalan (16 days) than on Kondor and Diamant. Moreover, the survival rate, from egg to adult, of O. minutus on TSM-infested leaves of Savalan (52.8%) was better than on Kondor and Diamant. The fecundity of O. minutus reared on TSM-infested leaves of Savalan (11.7 eggs/female) was significantly higher than on Agria, Morene, Kondor and Diamant. The intrinsic rate of natural increase and the population growth rate of O. minutus were highest when reared on TSM-infested leaves of Savalan (rm = 0.089 day−1 and λ = 1.094 day−1). These results suggest that using Savalan cultivar integrated with O. minutus could result in improved efficacy of this predator and lead to effective and more sustainable management of T. urticae in potato fields.