Journal mondial de la biologie, de l'agriculture et des sciences de la santé

Abstrait

IMPACT OF INSECT PEST ON YIELD OF RICE: CASE OF VARIETIES IR 46 AND NERICA 3 IN AGROECOSYSTEME OF MAGA FAR NORTH OF CAMEROON

SADOU Ismaël, WOIN Noé, DJONWANWE, MBONGAYA Samy Eware & BOUBAKARY NASSOUROU BADAI

This present study which is base on the effect of pest insects on the production of rice was done in the Far North Cameroon in the irrigated rice ecosystem of Maga. On one part, it consisted of the determination of the biological diversity of pest insects of rice in the rice ecosystem of Maga, to evaluate the damages and the dynamism of pest insects on the phenologic stage of rice and on the other part and to evaluate the effect of insecticide lynx on the pest insects and the production of rice. A split plot disposition of two rice varieties (irrigated rice variety IR 46 and the rainy season rice variety NERICA 3) and two treatments (control and chemical treatment) were adopted. The insects were captured with the help of a sweep net on every portions on the phenologic stages of rice, from the 15th day after planting to harvesting. This method of collecting insects consists of sweeping insects, on the portions or 50 sweeps per portion. These collections of pest insects on the two rice varieties have permited us to see the dynamism of pest insects on the different phenological stages of rice, and a knowledge on their abundance. The results obtained on the biological diversity have shown that 2465 pest insects of rice were collected on the IR 46 variety and 3264 on the NERICA 3 variety. Concerning the dynamism of the pest insects, we have observed a variation of the number of pest insects following the different phenological stages of rice. Concerning the damages due to the pest insects, lose due to these pest insects was evaluated at 49.98% total, 26.30% lose at the talling stage and 23.68% at the harvest on the two varieties. The chemical insecticide lynx have reduced the pest at a rate of 12.585% in the nursery, 20.4725% at the talling stage, 9.305% at the ear and 8.7325% at maturity. The output was obtained at 2.13 t/ha for the IR 46 variety and 1.91 t/ha for the NERICA 3 variety. This result permits us to say that many pest insects occupies the irrigated rice ecosystem of Maga, they are dynamic and leads to the damages on the rice production. The insecticide lynx used permit the reduction of the pest insects and hence increasers production.