The integrative toxicity effects of beta-cypermethrin on Propylea japonica larvae and Aphis gossiypii adults Effects of sublethal dosage of imidacloprid, abamectin and beta-cypermethrin on the development and reproduction of green of the morph of pea aphid (Acyrthosiphon pisum) Detection of beta-cypermethrin resistance in Shandong populations of Spodoptera exigua by competitive PCR amplification of specific allele