Reduced pruning and supplementary feeding in sweet pepper have a positive effect on the population development of Orius laevigatus

Abstract: Orius laevigatus is an effective biological control agent of thrips in sweet pepper.
This predatory bug has got an important role in integrated pest management strategies in sweet pepper production. In recent years it has been reported that it is increasingly difficult to build up a good population of O. laevigatus in sweet pepper in a timely manner. At the same time, sweet pepper growers have been pruning their sweet pepper plants with a greater frequency and intensity in order to enhance fruit size and thereby their profits. It is well-known that O. laevigatus lay their eggs in younger vegetative plant parts since the tissue is still soft and can be penetrated easily by their ovipositor. We hypothesized that pruning has a negative effect on the Orius population as with plant parts discarded onto the floor, many eggs will end up there, likely resulting in either the eggs drying out, or the eggs hatching but the nymphs unable to return to the crop due to great distance.
In this study, we investigated the effect of pruning of sweet pepper plants and supplementary feeding on the population development of O. laevigatus. We conducted a cage trial in a greenhouse with three different treatments: growers’ standard pruning, reduced pruning, and growers’ standard pruning plus supplementary feeding with Ephestia kuehniella eggs and Artemia spp. cysts. Our results show that the population development of O. laevigatus nymphs was significantly better in the reduced pruning and the supplementary feeding treatments, while no significant differences were found for O. laevigatus adults. The advice towards growers is to prune once every three weeks and to add supplementary food weekly to favour Orius population development.