The Relative Susceptibility of Some Rice Varieties to Sitophilus oryzae in Edo State, Nigeria

Rice is an important food cereal grown and consumed by many people the world over. In Edo State, Nigeria,rice is produced predominantly in Ekpoma, Irrua, Illushi, Agbede and Agenebode. This consists of both upland and lowland varieties. Its production is however- limited largely by weevil infestation particularly Sitophilus oryzae (L.) which is an economically important pest. This weevil affects stored rice by reducing its quality and causing a weight loss of the grains. Five new varieties – ITA 150, ITA 306, OS6 (Faro 11), Malong and American lamount were exposed to S. oryzae infestation at an average temperature of 28. 5 ± 0.2% and 78.0 ± 4.4% r.h. in a simulated warehouse condition. The measurement of the effect of the weevil was based on parameters such as loss of weight in the varieties, percentage of adult mortality, number of emerged progeny and number of damaged grains. ITA 150 was the most susceptible while ITA 306 was the most resistant 49 days after weevil infestation. More production of var. ITA 306 is suggested after further research