open access

Abstract

The damage caused by Noorda blitealis Walker (Lepidoptera: Crambidae) on Moringa, Moringa oleifera (Capparales: Moringaceae), a very important leafy vegetable in Niger, pushes producers to excessively use synthetic chemical pesticides. The present study was carried out in the laboratory for the parasitism test and at the station for the evaluation of the dynamics of predatory arthropods. The work aims on the one hand to test the parasitic capacities of two Trichogrammatoidea parasitoids sp. and Habrobracon hebetor respectively on the eggs and on the caterpillar of N. blitealis and on the other hand to evaluate the dynamics of the abundance of predator colonies in a Moringa plot, from a biological control perspective. At the end of these activities, the results obtained made it possible to determine that the average rate of emergence of individuals from a female of Trichogrammatoidea sp., on C. cephalonica eggs is 82.3% per day of infestation, or 13.6 individuals emerged per day of infestation. While the number of adults emerged from N. blitealis eggs is 4.1 individuals emerged per day of infestation (with a rate of 62.2% per day), significantly lower compared to the emergence rate obtained eggs of C. cephalonica. We observe that a total of 32.8 individuals on average emerged from a batch of ten larvae of C. cephalonica, from a female of H. bracon significantly higher than the nine individuals emerged from a batch of ten larvae of N. blitealis. In short, H. hebetor and Trichogrammatoidea sp. do not appear to be good candidates for biological control agents against N. blitealis. The study of the dynamics of insect colonies predatory on the larvae and eggs of N. blitealis, namely, ants, spiders and mantises, shows that their populations are present on the plants of two varieties of M. oleifera almost all during the year, with abundances varying greatly from one season to another.

Keywords: Noorda blitealis, Trichogrammatoidea sp, Habrobracon hebetor, Moringa oleifera, biological control, Niger