The granary weevil Sitophilus granarius is suppressed by the parasitoid Lariophagus distinguendus Forster (Hymenoptera: Pteromalidae)

The pteromalid wasp Lariophagus distinguendus is a promising candidate for the biological control of Sitophilus granarius and other stored-product pest beetles. Therefore, the ability of L. distinguendus to suppress population growth of S. granarius was examined over a period of 7 months. Ten female weevils were released in glass jars containing 2 kg of wheat. For 5 weeks, 0, 2, 5, 10, 20 or 50 parasitoids were added to the jars weekly and the numbers of weevils emerging were counted after 12, 16, 20, 24 and 28 weeks. Regardless of the number of parasitoids added, the population size of S. granarius was reduced in the presence of L. distinguendus by 79-94% over the whole period. This indicates that L. distinguendus is able to significantly suppress the population growth of stored-product pest weevils.