Life history and population growth parameters of the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae) fed on 10 rice cultivars and lines

Abstract

AbstractThe rice weevil,Sitophilus oryzaeL. (Coleoptera: Curculionidae), is one of the most destructive pests of stored cereal grains globally. In this study, we evaluated the grain resistance of different rice cultivars (Anam, Gilar, Hashemi, Keshvari, Rash, and Tisa) and lines (8608, MN-7, TH-1, and TH-2) using life history and life table parameters ofS. oryzaeunder laboratory conditions (28 ± 1°C, 70 ± 5% relative humidity, and complete darkness). The immature survival ofS. oryzaedecreased significantly when it was reared on Rash. Among tested grains, developmental time was the longest on Rash and the shortest on Hashemi. Compared with the other cultivars and lines, the fecundity (number of eggs laid) was significantly lowest on Rash. The highest intrinsic rate of increase (rm) was recorded inS. oryzaereared on Hashemi and the lowest was on Rash. The grain weight loss (%) was the highest whenS. oryzaewas fed on Anam and TH-1, and lowest when it was reared on Rash. Significant negative correlations were recorded between the starch, protein and total phenolics content of tested grains and fecundity,rm, net reproductive rate (R0), and finite rate of increase (λ) ofS. oryzae. The present research revealed that Rash cultivar was more unsuitable toS. oryzaethan the other cultivars and lines because of slow developmental time, poor fecundity, low grain weight loss and lowrmvalue on this cultivar. Our results could help to select resistant rice cultivars toS. oryzaefor production of transgenic grains.