Green Challenges: Systeemaanpak biologische plaagbestrijding met gebruik van functionele biodiversiteit : Deel 1: Chrysant

The goal of the research described in the report was designing and testing a systems approach for pest control in chrysanthemum on the basis of functional biodiversity. The low pest tolerance, harvest of the complete plants and the short cropping cycle of chrysanthemum form a challenge for biological pest control. They imply respectively that there are naturally no or only little food sources in the crop for natural enemies, that natural enemies are eliminated with the crop at harvest, and that there is only a short time period for the establishment of a so-called ‘standing army’ of natural enemies. As a first step, an overview was made of the most important pests and natural enemies, and the potential chances and bottlenecks for a systems approach of pest control in chrysanthemum. Subsequent research was focused around a strategy based on a biological start with generalist predatory bugs (Orius sp.) and predatory mites (Transeius montdorensis) combined with several additional food sources and the elicitation of induced crop defenses through enrichment of the microbiome of the soil. In a series of greenhouse experiments the effect of this strategy on the control of Western flower thrips (Frankliniella occidentalis) and the cotton aphid (Aphis gossyppi) was investigated. The inoculation of rooted chrysanthemum cuttings with a relatively high density Orius laevigatus predatory bugs, and full-field application of high-quality Artemia (Biobee Biological Systems) as an additional food source, resulted in a good establishment of Orius in the crop and a good control of Western flower thrips and cotton aphids. No effects of the tested soil microbiome enrichment treatments on thrips and aphids were observe