Complementary diets for predatory mites to improve biocontrol on vegetable crops

Abstract: Several strategies have been developed to improve the establishment and maintenance of predatory mites on vegetable crops. Some alternative foods have been implemented like pollen and Artemia cysts, although the major step has been the formulation of sachets that can release populations ‘á la carte’. This has contributed to favor the biocontrol but there are still circumstances where successful control of pests is not yet achieved due to low ratios of predators to prey. A good example is the cucumber protected crops in Spain, where high infestations of thrips damage the fruits on winter.In the present work, the application of factitious astigmatid mites at the top of plants has been evaluated as an alternative food to favor the development of Amblyseius swirskii. Trials have been conducted in a cucumber crop in an experimental greenhouse during two different seasons, winter and spring of 2015. Additional trials were conducted in 6 cucumber and 2 melon crops in commercial greenhouses during the spring of 2015.The results showed that A. swirskii can increase up to 4-5 times compared to standard releases when complementary food is not added. This allowed guaranteeing a preventive control of the main pests on cucumbers and melon. A strategy for winter and spring conditions is discussed.Abstract only