If at the end of last season the crop was not completely thrips free it is likely that the pest will again become active in January, with the arrival of the new plants. The remaining thrips will have survived disinfection and thrive when greenhouses are reheated after New Year. Growers are preventively deploying predatory mites.
Bart Elseviers, technical advisor at Biobest explains: "A successful fight against thrips should begin before the new plants are planted." He advises pepper growers in to preventively use mites in January to prevent the resurgence of remaining thrips.
"Pepper growers who were completely thrips free at the end of their previous cultivation are clearly one step ahead in this period. The best thing they can do is hang sachets with Amblyseius cucumeris (1 bag for every three stems) in combination with the deployment of Amblyseius degenerans. This is an economically beneficial strategy," Bart explains. "The sachets contain enough nutrition for at least six weeks so cucumeris mites are continuously released into the crop. The degenerans population develops slowly but will prove beneficial later in the season because it also helps combat red spider mite. In the absence of prey the development of degenerans can be accelerated by feeding them Nutrimite™, Biobest’s food supplement."
For growers who had problems with thrips at the end of the previous cultivation, Bart advises the use of Swirskii. "Preventive supplementary feeding with Nutrimite is indicated as long as there is no presence of thrips to feed the Swirski mites. Once thrips is detected, supplementary feeding becomes unnecessary."
Bart: "It is therefore increasingly important to check the presence of thrips during this period. I strongly advise growers to hang blue sticky traps - between 20 and 50 units per hectare."