Relative resistance of maize varieties against maize weevil, Sitophilus zeamais (Motschulsky), (Coleoptera: Curcolionidae)

The maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), is one of the most damaging pests of stored cereals causing severe damage to stored grains. In current investigation, six open pollinated maize varieties viz. JALAL (white), AZAM (white), SADAF (yellow), ZARD LOCAL (yellow), KASHMIRI (yellow) and PAHARI (white) were screened out in the laboratory of Entomology Department, Faculty of Agriculture, Gomal University, Dera Ismail Khan, Pakistan for their relative susceptibility/resistance to maize weevil. The experiment was laid out following completely randomized design (CRD) with 5 replicates. Results revealed that minimum (23.8) days to adult emergence of maize weevil were recorded when it was reared on variety Azam; whereas; maximum (34.2) days were recorded on variety Sadaf. Total number of F1 adults emerged were maximum (91) in Azam while minimum (62) in variety Sadaf. Percent infestation of maize kernels was maximum (39.01%) in Azam while minimum (25.80%) was recorded in variety Sadaf. Percent weight loss was maximum in Azam i.e. 26.12% while minimum percent weight loss (16.88%) was recorded in Sadaf. Maximum longevity (68.4 days) of adult weevils was recorded on Azam while minimum (53.4 days) was recorded on variety Sadaf. All the tested varieties had no significant effect on the sex ratio of emerged weevils. High germination percentage was recorded in Sadaf (90%) whereas; low germination was found in Azam (57%). The grain hardness test indicated that yellow varieties including Sadaf, Zard local and Kashmiri had maximum hardness having 317, 302.33 and 296 N grain hardness, whereas; white varieties i.e. Pahari, Jalal and Azam had minimum values of grain hardness i.e. 264.33, 251.66 and 238.33 Newton. The present work has shown that Azam is the most susceptible variety and should not be stored for longer periods whereas; Sadaf is the resistant variety against maize weevil.