Comparative susceptibility and weight loss of Wheat grains and flour due to Tyrophagus putrescentiae (Schrank)

Investigations on the comparative susceptibility of wheat grains and flour due to Tyrophagus putrescentiae showed that the number of eggs and mobile population of T. putrescentiae was statistically more on wheat flour (1742.73 eggs, 2517.73 mites/100g flour) than the number of eggs on wheat grains (519.87 eggs, 643.16 mites/100g grain). During six months study period, monthly observations showed significant increase in fecundity and number of mites from 257.50 eggs, 301.56 mites/100g wheat after 30 days to 2117.30 eggs, 3605.53 mites/100g wheat after 180 days of infestation. Amongst the two forms of wheat, % weight loss was significantly more (1.9%) on wheat flour, corresponding to high population as compared to wheat grain (0.7%). Per cent loss was 0.1, 0.2, 0.4, 0.8, 1.2 and 1.4 for wheat grains at 30, 60, 90, 120, 150 and 180 days. Corresponding values for wheat flour were 0.4, 1.3, 1.7, 1.9, 2.2 and 3.6% weight loss.