Inventaire Des Insectes Ravageurs et Vecteurs du Virus De La Panachure Jaune du Riz Dans Les Ecosystemes Rizicoles De La Region De L'extreme-nord du Cameroun

Insect vectors of the Rice Yellow Mottle Virus (RYMV) were studied in 2010 in the major irrigated rice ecosystems of Maga and Yagoua and in upland rice fields of Maroua in the Far-North province of Cameroon. Sampling of the insects vectors was carried out every forth night in upland rice fields and irrigated rice fields using a special sweep net and a D-VAC. From the samples collected in the various sites, the population of dominant insect vector, were analysed in relation to the phenological stage of the rice plant. The diversity and the frequency of the major groups of potential predators and parasitoids were also analysed. The following vectors of the Rice Yellow Mottle Virus were identified at different stages of growth of rice in irrigated rice fields and in upland rice fields: Chnootriba similis (Coleoptera: Coccinellidae), Chaetocnema pulla (Coleoptera: Chrysomelidae), Trichispa sericea (Coleoptera: Chrysomelidae), Locris rubra (Hemiptera: Cicadellidae), Nephotettix nigropictus (Hemiptera: Cicadellidae), Sogatella furcifera (Hemiptera: Delphacidae), Cofana spectra (Hemiptera: Cicadellidae), Recilia dorsalis (Hemiptera: Cicadellidae), Niparvata lugens (Hemiptera: Delphacidae) and Diopsis thoracica (Diptera: Diopsidae). The populaton size of these vectors was particularly important at the vegetative stages of the rice plant. The irrigated rice ecosystems were infested mainly by the insect vector of the Rice Yellow Mottle Virus. Nephotettix nigropictus (Hemiptera: Cicadellidae) which was the most abundant specie was collected at the vegetative stages of growth of the upland and irrigated rice fields. The predators sampled in the field included: Araneus sp. (Araneae: Araneidae), Tetragnatha sp. (Araneae: Tetragnatidae), Pardosa injucunda (Araneae: Lyconidae), Xanthadalia effusa (Coleoptera: Coccinellidae). The parasitoids that were sampled included Hydrellia griseola (Diptera: Ephydridae), Bracon sp. (Hymenoptera: Braconidae), Xiphosomella sp. (Hymenoptera: Braconidae) and Platygaster sp. (Hymenoptera: Platygasteridae). The parasitoid Hydrellia griseola (Diptera: Ephydridae) and the predator Araneus sp. (Araneae: Araneidae) were the most abundant natural enemies of the insect vector in upland rice fields in Maroua and irrigated rice fields in Maga and Yagoua.