To compare the performance of the populations of aphids and parasitoids from apple and Pyracantha, on both host plants.

1.- To determine the specifíc status based onmorphological characters of the populations of aphids of the genus Eriosoma that use Malus domestica and Pyracantha cocinea as host plants. 2.- To evaluate the performance of the populations of aphids of the genus Eriosoma that use Malus domestica and Pyracantha cocinea on both host plants. 3.- To evaluate the performance of the populations of the parasitoid A. mali that attacks Eriosoma aphids on Malus domestica and Pyracantha cocinea on both host plant. 4.- To isolate microsatellite markers for A. mali and to determine their level of polymorphism. 5.- To deteniiine the genetic structure and gene flow of the populations of A. mali on Eriosoma aphids from P. coccinea and M. domestica. 6.- To determine the genetic structure and gene flow of the populations of A. mali in apple orchards of Central Chile and compare with the genetic structure of its aphid host.