Persistence and Toxicity of Two Plant Extracts to Some Stored Product Insects

Abstract

This work aims at evaluation the efficiency of the acetone and petroleum ether extracts of Cubeb fruits Piper cubeba (L.) and Thyme flowering buds Thymus vulgaris (L.) against the adults of Sitophilus oryzae (L.), Rhizopertha dominica (F.) and Tribolium castaneum (Herbst). Also, persistence of the two plant extracts compared to malathion and pirimiphos-methyl (actellic) using the most sensitive insect species (S. oryzae), was investigated .Results showed that , the efficiency of the two plant extracts was concentration and exposure period -dependent. At the highest tested concentrations (2&1%w/w), the acetone extract of P. cubeba and petroleum ether extract of T. vulgaris were highly effective against S. oryzae and R.dominica adults, while, T. castaneum adults were the least sensitive . On the other hand, the petroleum ether extract of P.cubeba and the acetone extract of T.vulgaris indicated lower effectiveness against the three tested insects even after two weeks from treatment. The results also showed that, malathion and pirimihos methyl indicated clearly longer residual toxicity than the two plant extracts.

Insecticidal Impact of some Natural Oils and their Nano -Emulsions on Sitophileus oryzae

“…The insects were removed from the grains and left inside the jars until the emergence of F 1 progeny according to the method described by (El-Lakwah et al,1992) to determine the reduction percentages in adults progeny by the following equation: The decrease in wheat grain weight resulting from infection with S. oryzae was estimated after three months of treatment after screening the insects from the wheat grains, and the percentage of weight loss was calculated as dry weight loss with the equation (Harris and Lindbland, 1978):…”

Comparative Efficiency of Selected Chemical and Bio Pesticides against some Stored Grain Insects

“…Organophosphorus (OP) insecticide such as Malathion is being used as a protectant substance against stored grain insects during storage till now. Also, several pests now resistant to (OP) insecticides, Rhyzopertha dominica were resistant to Malathion (El-Lakwah et al, 2004). Subsequently, resistance to Malathion was noticed from different parts of the countries (Srivastava et al2001).…”