a1 Imperial Bureau of Entomology.
There are three main parasitoids and one very efficient predator associated with Perrisia pyri in France. Of these, at least during July and August, the predacious Capsid, Pilophorus perplexus, achieves the greatest destruction of midge larvae.
The two species of Platygasterids differ in several points of ethology from the species of the same or adjacent genera attacking Contarinia pyrivora. They are both egg-parasites, developing very slowly in the midge larvae during the growth of the host. Their action appears to be largely complementary, corresponding to morphological differences in the organs of oviposition. Their life-history is very imperfectly known.
Torymus abbreviatus is extremely efficient. Its eggs are laid within the curled leaf among well-grown midge maggots on which the larva lives as an ectoparasitoid. The duration and location of the pupa stadium is unfortunately not yet known.
Some half a dozen other enemies were found to play a less important part than the preceding.