Intensive research on leafminer fly (LMF) population dynamics, including the influence of climatic conditions and the role of natural enemies, is under way. There is evidence of diapause in endoparasitoids collected in winter and autumn. H. arduine represented 91 percent of the diapausing parasitoids in the Cañete Valley and 62 percent in La Molina, Peru. The factors that induce and terminate the diapause are not known.

Several species of weeds that host LMF may also be considered natural reservoirs of the parasitoids. It is interesting to note that the relative abundance of parasitoids varied with weed species. CIP scientists sampled a total of 25 different species of weeds. In a study on the capacity of parasitoids to survive after insecticide sprays, they found that Diglyphus sp. was able to survive insect growth regulator treatments.

Sticky yellow traps had a wide acceptance by farmers, probably because they see the flies trapped on the surface. In experimental plots, six traps captured 2.5 million flies and 154,000 parasitoids in a 1100 square meter area during the cropping season.

In experimental plots using a susceptible cultivar (Revolución), a selective insecticide, and monitoring of the timing of application, two sprayed plots yielded 1.1 kilograms per plant while the control plot yielded only one third of a kilogram per plant. The average number of sprays in the Cañete Valley experimental area was 10.

The first pilot area for LMF management was established in the Tambo Valley (southern Peru). In a two-year period, participating farmers benefited from a reduction in the number of insecticide sprays from six per season to an average of one. Farmers are increasingly asking to join the IPM program.