Insecticidal activities of the crude extract from the Calli induced from Derris elliptiea (Roxb.) Benth against Pieris rapae L. (Lipidoptera: Pieridae)

The crude extract of the calli (CEC) from young leaves of Derris elliptiea (Roxb.) Benth demonstrated strong antifeeding, contact poisoning and growth inhibiting properties against Pieris rapae L. The values of AFC₅₀ measured at 1 day and 2 days after treating was 2.207 ppm, 1.482 ppm respectively, compared with the crude extract of roots (CER) 2.375 ppm and 1.690 ppm to 5^th instar larvae of P. rapae relatively. The value of LD₅₀ of CEC by topical application was 0.283 μg per larva after 1 day while the values of CER and the standard rotenone (SR) observed little toxic than CEC were 0.327 μg per larva and 0.502 μg per larva respectively. The values of LC₅₀ (the median of concentration for inhibiting weight increase) of CEC were 2.050 ppm, 1.170 ppm after 1 day and 2 days respectively, CER and SR showed 1.856 ppm, 1.239 ppm, and 0.967 ppm, 1.190 ppm relatively. It was found that the development of pupae was manifestly inhibited by CEC, and the percentage of malformed pupae reached as high as 87.50% which were followed by SR 82.50%, CER 72.50% compared with the control 5.0%. When the pupae were treated with CEC, the percentage of adult emergence was the lowest 22.22%, and when with the other two CER and SR was 73.34%, 53.33% respectively compared with the control 94.30%. Eggs were greatly affected after treating with 50 ppm CEC, CER and SR, and the percentage of egg hatching decreased significantly to 14.56%, 25.44% and 19.96% respectively.