Optimal Mechanical Exclusion Devices for Management of Khapra Beetle in Stored Wheat

Abstract

The effect of mechanical exclusion devices and its number in combination viz. probe trap (A; 1-3), two-in-one trap with 3 mm perforations (B; 1-5) and two-in-one trap with 2 mm perforations (C; 1-3) were investigated to test the efficiency of these traps for trapping larvae and adults of khapra beetle Trogoderma granarium Everts. Colour change and weight loss (%) happening in wheat stored in bins of 50 kg capacity for six months were used as the criteria. The experiments were planned using a three-factor-three-level Box and Behnken design of response surface methodology and were optimized for maximum trapping, with minimum change in colour and weight loss. Analysis of variance (ANOVA) revealed significantly (p<0.05) higher effects of quantity (number) of two in one trap with 3 mm perforations followed by two in one trap with 2 mm perforation on total trapping efficiency. Colour change and weight loss in stored wheat exhibited a negative relationship with trap capture. Among the process parameters studied, the probe trap and its number in experimental combination demonstrated a significantly lower effect on the response variables. The optimal combinations of mechanical exclusion process parameters obtained by numerical optimization technique for trapping larvae and adults were 3:4:3 and 2:5:3 (probe trap: two in one model trap 3 mm: two in one model trap 2 mm) with desirability of 0.61 and 0.63, respectively.