Biological control of thrips pests (Thysanoptera: Thripidae) under greenhouse conditions in Transylvania, Romania

Abstract

In present, vegetable cultivation faces significant challenges for two reasons: (i) cultivators have to produce healthy, first-class goods, and (ii) vegetables are allowed to contain only a specified pesticide residue. Development of insecticide resistance as a result of repeated insecticide treatments is causing difficulties to cultivators, who have paid attention to biological control methods over recent years. In Romania, pepper sprouting represents a prominent place in greenhouse vegetable production. Under greenhouse conditions, one of the most dangerous pests of peppers is the western flower thrips (Frankliniella occidentalis), which can trigger high economic losses. In recent years, several populations have been found resistant to insecticides and other active compounds, therefore, in our experiments, performed under greenhouse conditions, we used the predatory mite Amblyseius swirskii and the pirate bug Orius laevigatus against the western flower thrips. In addition to thrips, we monitored the growth and spread of introduced beneficial organisms based on collected flower samples. We also evaluated the relationships between beneficial organisms and greenhouse climate data. Introduction of natural enemies has proven a success of biological plant protection, as thrips did not cause economic losses in our experiment.