Quality control of the parasitoid Aphidius colemani (Hym., Aphidiidae) used for biological control in greenhouses

Since several years the aphid parasitoid Aphidius colemani is used in greenhouses to control Myzus persicae and Aphis gossypii. Aphidius is reared by different commercial producers under artificial conditions and due to inbreeding runs the risk of losing some of its quality. The IOBC (International Organisation for Biological Control) designed quality control tests and guidelines to maintain products of high quality and to avoid negative advertisement against biological control. This study was set out to determine the quality of A. colemani from four commercial producers using tests proposed by the IOBC in conjunction with additional parameters. Quality control was performed after all packaging procedures and transport. Quality of the following parameters was assessed under laboratory conditions: parasitoid species, quantity, adult mortality, sex ratio, longevity, flight capacity, parasitation rate and number of hyperparasitoids. Eleven shipments of 1000 parasitoids each were used for the tests. The results showed that the quality of A. colemani was frequently unsatisfactory. Quality of products from the same producer often differed as much as products between producers. Conditions during transport had a great influence on the quality of the parasitoids. Different parameters to improve the present lack of quality are discussed.