Abstract

PAVELA, Roman; VRCHOTOVA, Nadezda  and  ŠERA, Bozena. Growth inhibitory effect of extracts from Reynoutria sp. plants against Spodoptera littoralis larvae. Agrociencia [online]. 2008, vol.42, n.5, pp.573-584. ISSN 2521-9766.

Laboratory studies were conducted to determine the effects of methanolic extracts from three Reynoutria species on feeding, development and mortality of larvae S. littoralis. The extracts of all three Reynoutria species did not reveal feeding deterrence in the Spodoptera littoralis larvae. However they significantly decreased the larvae growth and the efficiency of conversion of the ingested and digested food. Conversion of the ingested food was lower, when compared with control larvae. The use of food provoked prolongation of the larvae development and chronic toxicity. Even if extracts of all three plant species were effecting the larvae mortality with the same results (LC₅₀ ranged from 0.5 to 1 mg g^-1 in all extracts), the impact on growth inhibition in the larvae varied. The most efficient extract was R.xbohemica interspecific hybrid (LC₅₀ was 1.24 mg g^-1), then the extract of R. japonica (LC₅₀ of 6.72 mg g^-1), and the least efficient was the R. sachaliensis extract (LC₅₀ of 9.48 mg g^-1).

Keywords : Reynoutria; Spodoptera littoralis; growth inhibition; botanical insecticides; toxicity test; plant extracts.

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