Growth Inhibiting Effects of Three Different Plant Extracts on Tribolium castaneum (Herbst) (Tenebrionidae: Coleoptera)

Petroleum ether, acetone and ethanol extracts of neem, sweet flag, and turmeric were evaluated for their growth inhibiting effects on the Tribolium castaneum at the application rate of 1000, 500, 250 and 125 μg/g food media. Petroleum ether extracts showed the lowest number of larvae produced (34.00) in 1000 μg/g neem extract. Acetone extract of sweet flag showed minimum and significantly lower number of larvae produced (8.00) at 1000 μg/g, whereas ethanol extracts of turmeric showed minimum numbers of larvae (106.30) at 1000 μg/g application rate. Maximum inhibition ratio of pupation was found as 81.18 % at 1000 μg/g dosage of petroleum ether extract of sweet flag resulting into 8.75 pupae. Acetone extract of sweet flag showed minimum numbers of pupae produced (8.00) at 1000 μg/g of sweet flag, whereas ethanol extract of sweet flag showed minimum numbers of pupae (41.75) at 1000 μg/g. Petroleum ether extract of sweet flag showed a maximum inhibition ratio (40.00 %) resulting into 5.25 adults produced at 1000 μg/g. Acetone extract of sweet flag showed the lowest numbers of adults produced (8.00) at 1000 μg/g. Ethanol extract of neem showed lower numbers of adults (35.25) at 1000 μg/g dosage, followed by 38.50 in sweet flag and 52.75 in turmeric at the same application rate.