Study of the insect pest African rice midge Orseolia oryzivora in the far north Cameroon

The objective of the study was to increase rice production by screening three (03) varieties of NERICA (New Rice for Africa) rice in the face of attacks from the African rice midge (Orseolia oryzivora) and to integrate efficient biological control in rainfed rice cultivation. During the rice crop cycle, each phenological stage of the plant is sampled every two weeks using the D-VAC vacuum cleaner and sweep net throughout the crop season given that this sampling frequency corresponded at a specific phenological stage. White hearts are sampled during the bolting stage of the plant. It consisted of randomly taking 20 plants of white hearts from each plot. The NERICA 3 variety is more sensitive than the other two varieties because it has more African rice midge population. African rice midge population abundance varies depending on the collection method (Sweep-Net and D-VAC). Collection using the D-VAC motor vacuum cleaner was found to be more efficient than that carried out by the Sweep-Net. Only 5 live African rice midge individuals were recovered out of the 38 observed. Mortality rates of 70% and 95% are observed respectively on NERICA 1 and NERICA 3. On NERICA 1, of the 14 dead pupae, 5 had Aprostocetus sp larvae while on NERICA 3, 8 Aprostocetus sp larvae were extracted of the 11 dead pupae. This high mortality rate is largely due to parasitism by Aprostocetus sp larvae and unfavorable environmental conditions during the migration of African rice midge larvae from the leaf blade to the base of the stem.