Efficacy of Echium spp. water extracts as post-harvest grain protectants against Plodia interpunctella

Abstract

Water extracts of three plant species of the genus Echium (E. italicum L., E. vulgare L. and E. rubrum Jacq.) were tested under laboratory conditions for their activity as potential post-harvest grain protectants against Plodia interpunctella (Hubner, 1813) (Lepidoptera: Pyralidae) larvae. Antioxidative activity and total phenolic, flavonoid and tannin contents in plant extracts were determined. The larvicidal assays were conducted with the local population of P. interpunctella from Central Serbia on kernels of Takovoanka winter wheat cultivar. The experiment was set as factorial 3x3x3x3 block design type. Three groups of larvae of different maturity were used. The larvae were exposed to three different concentrations of water extracts (1%, 2% and 5%) of three listed plant species. Mortality was registered daily during 96 hours and the efficacy was calculated using Schneider-Orelli's formula. The largest number of dead larvae was recorded in the treatment of 1% extract of E. italicum on youngest group, after 72 and 96 h. Extracts of E. vulgare and E. rubrum did not show high larvicidal effect.