Predatory mites as potential biological control agents for tomato russet mite and powdery mildew on tomato

Tomato plants are attacked by numerous pests and diseases, including the tomato russet mite Aculops lycopersici and powdery mildew, Oidium neolycopersici. Natural enemies of tomato pests are often hindered by the tomato trichomes, while russet mites live under and among these leaf hairs and are therefore protected from these enemies. To find natural enemies that are adapted to tomato and its trichomes, we collected a predatory mite, Amblyseius herbicolus, and an iolinid mite, cf. Homeopronematus anconai sp. nov., from tomato plants in the field. We investigated their potential as biological control agents for pests in this crop. We show that both predators were able to feed and reproduce on russet mites. Subsequently, we show that the iolinid effectively controlled tomato russet mites and powdery mildew on isolated tomato plants, whereas A. herbicolus disappeared from the plants. Altogether, our results show that cf. H. anconai sp. nov. is an efficient biocontrol agent of two key pests on tomato plants. Our results thus contribute to the recent trend of using predators that are effective in controlling both a pest and a pathogen, a promising new strategy for biological crop protection.