Susceptibility of certain wheat varieties to the infestation by Rhyzopertha dominica (F.) and Tribolium confusum (du Val)

Abstract

Eight Egyptian flour wheat varieties were assessed in order to determine their appropriate level of susceptibility to Rhyzopertha dominica (F.) and Tribolium confusum (du Val). Free choice test for attraction insect adults was used in the first experiment at time interval ranged from 0.125 to 5 days post infestation. At days, results showed that the lowest attracted numbers of R. dominica adults were 5.00 and the highest ones were 22.67 for SAKL8 and SIDS1 varieties, respectively. The varieties can be arranged descendently according to the attracted numbers of R. dominica as follow: SAKL8, SAKL1, BACANORA, DEBEIRA, , GIZA168, GIZA164, SIDS6 and SIDS1. The descending order results were obtained for T. confusum could be the similar. Statistical analysis demoed significant differences between the numbers of the eight varieties. In the second experiment, the numbers of F1 and the duration of offspring of each stage were determined. Based on the Dobie Index (D.I.) for R. dominica, SAKL8, DEBEIRA, BACANORA and SAKL1 were found to be resistant varieties. While the SIDS1 and SIDS6 varieties have a moderate resistant. In the case of T. confusum all varieties showed a degree of resistance, except SAKL8 and SIDS1showed a moderate resistant. The BACANORA cultivar showed the lowest D.I. value in the two tested insect species.  The obtained results can give a better understanding to the stored-grain managers regarding to the prospective differences in wheat susceptibility to R. dominica and T. confusum infestation