Pirates to the rescue: Biological control of thrips and food web interactions in horticulture using omnivorous predators

Summary

Global trade has increased the spread of invasive pests, damaging crops and ecosystems. Thrips are particularly problematic, damaging plants directly and spreading plant viruses. This PhD research focused on identifying biological control agents against leaf-dwelling thrips such as Echinothrips americanus and Scirtothrips, studying interactions among multiple pests and predators, and assessing plant characteristics that affect predator efficacy. Furthermore, a novel deep-learning algorithm was developed to assess predation activity accurately on sentinel prey. Experiments revealed that Orius predators vary in their reproductive success, plant preferences, and effectiveness against flower or leaf-dwelling pests. Combining different Orius species was further found to improve overall pest control on gerbera. Preventive predator releases supplemented with alternative food were shown to effectively suppress Scirtothrips on strawberry. Overall, this research provides insight into the behaviour and efficacy of important biological control agents, as well as strategies to enhance biological control of thrips and other pests.