Résumé:
Aphids are small phytophagous insects, they cause considerable damage to protected crops. In pepper cultivation, the species Aphis gossypii and Myzus persicae are the most dominant. Our study focuses on the population dynamics of these two species and the use of predatory insects to control the aphid. The results obtained show a maximum relative abundance of 986 individuals as of May 5, under the average temperature of 35°C in Aphis gossypii and a maximum of 562 individuals for Myzus persicae at the same date. However, colonies of aphids are very important in the greenhouse, on the other side, the number as soon as predators (ladybugs, hoverflies and midges) is low. The relative abundance in predators is 60, 127 and 190 respectively by ladybugs, hoverflies and gall midges. In addition, a high predation rate is reported in ladybirds compared to midges and hoverflies. Also, we found that 1st and 2nd larval stages of aphids are very sensitive to predation with high rates of the order of 210 to 189 for ladybugs, 106 to 97 for hoverflies and finally, between 59 and 65 for gall midges.
