It was found that effectiveness of predatory mite Phytoseiulus persimilis in control of Tetranychus urticae increased on cucumber plants cultivated with the presence of Pseudomonas fluorescens (PGPR), as compared to the plants without bacteria. Six weeks after predator introduction the spider mite population was 3 times lower on the plants cultivated with bacteria than on the plants without bacteria. The ratio prey: predator on bacterized plants was almost 3 times lower than on nonbacterized. Predatory mite Amblyseius swirskii evidently reduced the number of trips larvae in both groups of cucumber plants, untreated and treated with biostimulators, however, 3 weeks after predator introduction the highest number of trips was found on the plants treated with Siapton. These plants could be less attractive to predator than the others.
Frankliniella occidentalis is the most important pest in greenhouse crops. Successful control of this pest is very difficult. In laboratory and greenhouses studies predator mites Amblyseius swirskii and Amblyseius cucumeris showed a high efficacy used together in control of western flower thrips (83% mortality). Predators used separately were less efficacious against the pest (about 63% mortality). The studies showed neutral interaction of A. swirskii and A. cucumeris populations in control of western flower thrips.