Phenolic and lipophilic compounds of wheat grain as factors affecting susceptibility to infestation by granary weevil (Sitophilus granarius L.)

The impact of certain groups of polyphenolic (phenolic acids and alkylresorcinols) and lipophilic compounds (total lipids, fatty acids, sterols, tocols and carotenoids) on susceptibility of bread wheat (Triticum aestivum L.) kernels to Sitophilus granarius infestation was studied. In the experiments, six cultivars of spring wheat with comparable protein content, endosperm hardness and overall technological quality were used. Twenty grams of grain were infested by 10 pairs of beetles and stored for one week or eight weeks at 28±2°C and relative humidity of 60%. The intensity of growth and feeding of S. granarius varied significantly in the used cultivars. The antixenosis effect of the studied grain chemicals, observed after one week of infestation, was the lowest for Łagwa cv., which was characterized by the highest total lipid and sterol contents. Other cultivars showed a similar antixenosis effect. For antibiosis effect, the most attractive for S. granarius infestation was Ostka Smolicka cv., which was characterized by the lowest content of total phenolic acids. In contrast, the highest antibiosis effect was found for Arabella and Izera cvs. with the lowest values of sterol content and average values of other determined phytochemicals.