SUSCEPTIBILITY OF MAIZE SEEDS SPEICES TO INFESTATION BY KHAPRA BEETLE (Trogoderma granarium Everts, Coleoptera, Dermestidae)

Abstract

The present study included the effect of corn seeds species (Forage corn, Popcorn and Sorghum) and the effect of storage period (2 and 4) months on the population density and growth rate of khapra beetle in addition the effect of population density on the loss of weight and some of physical characteristics, germination percentage, (volume of 100 seed and weight of 1000 seed), The results indicated that the sorghum seed was more susceptible to infestation by Khapra beetle of all insect stage 61.67 and 215.67 insects for two storage periods 2 and 4 months respectively, followed as the forage corn (45 and 56.76) individuals, Then the pop corn (29.67and 46.67) individuals for two storage periods, respectively too, and the general mean of insect numbers for two storage periods were 45.45 and 106.37 insect. The results showed that the individuals growth rate was between 1.48 on pop corn seed at 2 months of storage period and 5.39 on sorghum seed at 4 months of storage period, the lower loss of seed weight reached (0.51) gm. at 2 months of storage period on the pop corn with the loss percentage 2.04%, and approached to higher loss on the sorghum (4.24) gm. with the loss percentage 16.95% at 4 months of storage period. The effect of insect infestation and storage period was greater on the physical characteristics under study, which the general mean of germination percentage for the two storage period decreased from 83.33% before infestation to 12.94% after infestation, and volume of 100 seed decreased from 11.65 to 8.88 ml. then the weight of 1000 seed reduced from 121.62. to 101.79 gm.