Predatieproeven met nieuw ontdekte natuurlijke vijanden van weekhuidmijten

Tarsonemids (Fam. Tarsonemidae) are an increasing problem in the cultivation of ornamentals. In Bromelia, they cause dammage as necrotic spots or redish stripes in the leaves and malformations of the inflorescence. Because of their tiny size and their hidden habitat, they are difficult to be controlled by predatory mites. Upon request by the Bromelia Growers Comitee of LTO Groeiservice and financed by the Horticultural Product Board, a small laboratory research has been conducted in order to find evidence of the predation by predatory mites. Five predatory mites were selected as potential predators of the Tarsonemidae mites due to their nutrional preferences, living environment and size. Four of the five selected mites, namely Neoseiulus reductus , Neoseiulus alpinus, Typhlodromips montdorensis en Neoseiulus barkeri showed a very good predatory behaviour on the offered prey. All of them notice the prey very soon and proceeded to what resulted in a very high percentage in succesfull predation. The predatory mite isolated from infected Bromelia plants, Lasioseius fimetorum was unexpectedly totally not interested in the offered prey, often walked over it without noticing it and did no efforts at all to feed himself with the prey. The results can increase the chance of succesful control of this pest in Bromelia. A necessary condition is that the predatory mites can colonize the host plants. Therefore, it is recommended to perform tests in order to evaluate the colonization of the crop at the plant level with the succesful predatory mites.