Ultrasonic extraction for preparation of plant extracts with bioinsecticidal effects on pest from seed deposits

Abstract

This paper describes the preparation of plant extracts using solid-liquid ultrasonic extraction (sonoextraction), the characterization of prepared extracts and their bioinsecticidal activity. The studied raw vegetal material:Primula veris, Achillea millefolium, Origanum vulgare and Artemisia absinthium, was collected from the spontaneous flora of Romania, Moldova region. To assess the efficiency of solid-liquid sonoextraction process, the influence of some operating parameters such as solid/liquid ratio, extraction time, extraction temperature, and extraction efficiency was studied. The qualitative study has in view the interpretation of UV-VIS spectra recorded for the extracts, and the quantitative study consists in the estimation of total polyphenols and flavonoids content of prepared vegetal extracts. The resulted data indicate that the content of polyphenols and flavonoids is dependent of the extraction temperature, extraction time and solid/liquid extraction ratio. The bioinsecticidal activity of Origanum vulgare and Artemisia absinthium extracts was evaluated on the Acanthoscelides obtectus (commonly named as ladybug bean) using two application techniques (i.e. direct and indirect application using a cellulose disk as a porous material impregnated with extract that allows controlled evaporation), being registered a mortality rate of adults in the range of 35-55%. Therefore, the studied extracts proved to be effective in controlling ladybug bean from seed stores.