Efficacy results of insecticides against Cydia pomonella, the codling moth, in Belgium during the last decade (1998-2007).

The codling moth is an economically important top fruit pest, with its major flight from May till August. We give an overview of ten years of results of efficacy field trials against the codling moth Cydia pomonella, with a number of commonly used products (diflubenzuron, fenoxycarb, flufenoxuron, indoxacarb, granulosis virus, methoxyfenozide and tebufenozide). All trials were executed according to EPPO guidelines. Trials were performed in the Belgian fruit growing area nearby Sint-Truiden, on apple or pear. Each product was sprayed repetitively at registered dose rates to cover the whole flight period of the codling moth, as monitored with pheromone traps. Applications were repeated at strict intervals (7, 14, 21 or 28 days). We show that the different active ingredients had diverse mean efficacies, ranging from 49% to 98%. In general low mean efficacies could be attributed to high variability between trials. Maximal efficacies were indeed high (80%-100%) for all except one "product-interval" combinations, whereas minimal efficacies ranged from 0% to 92%. Belgian fruit growers can thus choose from a large set of active ingredients for resistance management, but have to take variability in efficacy into account. The best and most constant efficacies were reached with Cascade 100 DC (flufenoxuron) at a dose rate of 44 to 50 g a.i./ha leaf wall area and with an application interval of 14 or 21 days.