Study of insects vectors of rice yellow mottle virus in the far north region of Cameroon.

The present study was carried out in the research framework conducted by the Regional Center of Agricultural Research of Maroua. This investigation aimed at making an inventory of insects vectors of rice yellow mottle virus (RYMV) in the Far-North of Cameroon. The insects vectors of rice yellow mottle virus was studied in the rainfed rice ecosystem of Maroua and in the main irrigated rice ecosystems of Yagoua and Maga in the Far North Region, Cameroon. In order to attain this objective, two collection methods were used. These included collection by D-VAC (vacuum trap) and collection by the Sweep net. The collection of the insect species with the two methods was done at the different phonological stages of the rice plant (nursery, heading, booting and maturity). The insect identification key of Heinrich and the family recognition key of Delvare and al., were used to identify the different species collected. From the samples obtained in the different rice-growing sites, the dominant structure of insect vectors of rice yellow mottle as well as their natural enemies was analyzed according to the phenology of rice. It appears from the inventory of insects in irrigated rice (Maga, Yagoua) and rainfed rice (Maroua) that this crop harbors many vectors of the rice yellow mottle virus. In the different rice-growing sites, we have numbers of vector insect individuals captured of 267, 286 and 385 respectively in Maroua (rainfed rice), Maga and Yagoua (irrigated rice). The vector insects captured are distributed as follows, eight species of vector insects in irrigated rice in Maga belonging to five families divided into three orders. In irrigated rice in Yagoua, eleven species of insects vectors of RYMV belonging to seven families divided into three orders were collected. As for rainfed rice in Maroua, thirteen vector insect species belonging to seven families and three orders were collected.