Screening of commercial wheat varieties against stored grain insect pests Sitotroga cerealella (Oliv.) and Sitophilus oryzae (L.)

Different wheat varieties were tested in the laboratory against Sitotroga cerelella & Sitophilus oryzae. Variety NARC-2011 was found highly susceptible. While, Faisalabad-2008 was found least susceptible in case of Sitotroga cerelella. Percent adult emergence, percent weight loss and damage grain were found highest in variety NARC-2011 and lowest in Faisalabad-2008. Size of the grain, moisture content and hardness did not individually affect the level of resistance but these along with other factors had a combined effect. Chemical composition of all six varieties was also determined and it also showed significant variations. In case of Sitophilus oryzae NARC-2009 was found highly susceptible, while Pars-09 was found least susceptible. Percent damage grains, percent adult emergence and percent Wt. loss was found highest in NARC-2009, while lower in Pars-09. Variety NARC-2011 showed maximum protein and carbohydrate content and was more damaged. The results on coefficient of correlation indicated that correlation between progeny and protein, carbohydrate was found positive. Further, the correlation between progeny, percent Wt. loss, 1000 grain Wt. and percent damage grain was found positive but it was negative with hardness. The correlation between development period, moisture, ash and fiber was found positive. The correlation of development period with protein and carbohydrate was found negative. Furthermore, the correlation between development period and hardness was found positive. Index of susceptibility was positively correlated with protein and carbohydrate. However, it was found negative with moisture, ash, fat and fiber and significantly different in case of moisture and fat. Further, the correlation between index of susceptibility, percent Wt. loss, percent damage grain and 1000 grain Wt. was positive. In case of Sitophilus oryzae, correlation between progeny, protein, fiber, carbohydrate, percent damage grain and percent Wt. loss was found positive. While, it was negative with moisture, ash and fat. Developmental period is positively correlated with moisture, ash, fat and carbohydrate. While, it is negatively correlated with protein, fiber, percent damage grain and percent Wt. loss. Index of susceptibility is positively correlated with protein, fiber, carbohydrate, percent damage grain and percent Wt, loss. While, it is negatively correlated with moisture, ash and fat.