Ringed micro-habitats as supplementations for predatory mites

Abstract: In augmentative biological control, the reproduction, survival and efficiency of
predatory mites can be improved by providing supplementations such as artificial microhabitats and alternative food sources. Building on previous results on food and micro-habitat supplementations for Neoseiulus cucumeris, the present study aimed to i) design a prototype of Ringed Micro-habitats (RM) easily usable in agricultural cropping systems and optimise its position on the plant; ii) test the effect of this RM on the reproduction of three predatory mite species: two generalists (Neoseiulus cucumeris and Amblyseius swirskii), and one specialist (Neoseiulus californicus); iii) test the effect of this RM on the reproduction of two phytophagous mite species: Polyphagotarsonemus latus and Tetranychus urticae.
We evidenced that A. swirskii preferred to lay eggs in the RM prototype when it was
installed in direct contact with the underside of a rose leaf instead of being suspended on the
plant. We also demonstrated that leaves bearing RM prototypes significantly increased the
reproductive output of both generalist predatory mite species, but they had no impact on the
reproductive output of the specialist species. In addition, the presence of RM on plants had no effect on the reproductive output of the studied pest species. Results indicate that the provision of supplementations such as the RM can favour generalist predatory mite reproduction with no risk on pest promotion, opening new avenues for more efficient biological control with predatory mites.