Orius laevigatus and O. majusculus as biological control agents for leaf-dwelling thrips pests
The leaf-dwelling thrips Echinothrips americanus and Thrips setosus (both Thripidae and formerly EPPO Alert List) can be pests of ornamentals and vegetable crops. Some control of these thrips can be achieved by applying insecticides to the leaf surface, but this can also disrupt biological control strategies that have been developed for other thrips species such as the flower thrips, Frankliniella occidentalis (EPPO A2 List). Generalist predatory mites that are widely used in horticulture for the control of several pests including F. occidentalis, have not proven to be very effective against E. americanus. The two predatory mirids (Hemiptera: Anthocoridae), Orius laevigatus and O. majusculus (both EPPO Augmentative BCA (PM 6/3)) were assessed for their behavioral interactions, predation, reproduction and development on F. occidentalis, E. americanus, and T. setosus. The biocontrol agents were more successful in consuming sedentary leaf-inhabiting thrips adults compared to the highly mobile F. occidentalis. Furthermore, O. laevigatus was more successful in subduing prey compared to the bigger predator O. majusculus. Female adults of O. laevigatus and O. majusculus killed 18 and 20 F. occidentalis adults, respectively, in 24 h, while the kill rate was two times higher when the biocontrol agents were offered E. americanus or T. setosus. Developmental and reproductive parameters of both biocontrol agents were more favourable when feeding on the leaf-inhabiting thrips compared to F. occidentalis. These results highlight that O. laevigatus and O. majusculus are both successful in capturing and killing E. americanus and T. setosus compared to the more agile F. occidentalis.
Sources
Mouratidis A, de Lima AP, Dicke M, Messelink GJ (2022) Predator-prey interactions and life history of Orius laevigatus and O. majusculus feeding on flower and leaf-inhabiting thrips. Biological Control 172, 104954. https://doi.org/10.1016/j.biocontrol.2022.104954