The toxicity of bean flour (Phaseolus vulgaris) to stored-product mites (Acari: Acaridida)

Abstract

AbstraktHUBERT J., NĚMCOVÁ M., ASPALY G., STEJSKAL V. (2006): The toxicity of bean flour (Phaseolus vulgaris) to stored-product mites (Acari: Acaridida). Plant Protect. Sci., 42: 125-129.Legume proteins were shown to have insecticidal activity against stored-product pests. Grain enriched by bean (Phaseolus vulgaris) flour inhibits the growth of stored-product mites. In this study, we tested the toxicity of bean flour to storage mites under optimal conditions for their population growth (i.e. rearing diet, temperature 25°C and humidity optimum 85% RH). Bean flour was added to the diet in one of eight concentrations: 0, 0.01, 0.1, 0.5, 1, 2.5, 5, 10%). The population growth of Tyrophagus putrescentiae, Acarus siro and Aleuroglyphus ovatus initiating from a density of 50 mites per 0.2 g of diet was recorded for 21 days. The enrichment of grain with bean flour suppressed the population growth of the tested species. These differed in their sensitivity to bean flour. Population growth was decreased to 50% in comparison to the control (rC 50 ) by the bean flour concentration of 0.02% in T. putrescentiae, 0.04% in A. siro, and by 4.87% in A. ovatus. The concentration of 5% bean flour in diets kept populations of A. siro and T. putrescentiae at the initial level. The results are discussed in the context of applying bean flour in the integrated control of stored-product mites.

Combination of the antifeedant bean flour and the predator Cheyletus malaccensis suppresses storage mites under laboratory conditions

“…Thus, our results support the suitability of the use of bean flour, as suggested by Fields (2006). At present, this strategy seems to be the most efficient and safe measure for the protection of grain against stored product mites (Hubert et al 2006(Hubert et al , 2007a.…”

“…At low bean flour concentrations, ranging from 1 to 5 g kg -1 , an increase of the A. ovatus population compared to the control was observed. A similar effect was found when bean flour was mixed into an optimal rearing diet for A. ovatus (Hubert et al 2006). The application of bean flour had no negative effect on the predatory mite, C. malaccensis.…”

“…The exact mode of action of the bean flour has not been revealed yet. Unknown proteins present in the flour seem to suppress digestion by mites (Hubert et al 2006;2007a). Our previous research showed that a-amylase inhibitor from pea applied to A. siro neither inhibited the a-amylase nor suppressed the population growth (Kluh et al 2005).…”

“…For stored product mites, a similar effect was attained by application of bean flour (Phaseolus vulgaris). The toxic potential of this flour to pest mites has been observed in experiments where bean flour was added to the diet (Hubert et al 2006(Hubert et al , 2007a. If the bean flour is not toxic to the mite predators, then its addition could increase the biocontrol efficacy.…”

Acaricidal effects of natural six-carbon and nine-carbon aldehydes on stored-product mites

“…Similar trends in sensitivity of A. siro and T. putrescentiae were observed in previous study. T. putresecentiae was more sensitive than A. siro in experiments using bean Xour-enriched diet (Hubert et al 2006b) and the acaricide AlleroV 175 CS (Hubert et al 2007). At present, the mechanism of aldehyde toxicity is unknown.…”