Field-scale evaluation on the efficacy of a novel benzoylphenylurea TXH09 against chewing insect pests harming vegetables and rice
Abstract Structure optimization of benzoylphenylurea inhibitors (BPUs) reduces the risk of resistance and facilitates rational use with good efficiency. TXH09 [N-((2,6-dimethyl-4-(heptafluoropropyl-2-yl)phenyl)carbamoyl)-2,6- difluorobenzamide], a new BPU compound, was developed by derivation from a heptafluoroisopropyl group and possesses better polarizability, lipophilicity and permeability. In this paper, field-scale evaluation on the efficacy of TXH09 was performed against vegetable pests (Laphygma exigua H., Plutella xylostella L., Spodoptera litura F. and Pieris rapae L.) and rice pests (Cnaphalocrocis medinalis G., Sesamia inferens W. and Chilo suppressalis W.) in different regions of China. TXH09 was delivered as 5% emulsifiable concentrate (EC) and 5% water dispersible granules (WDG). Insect populations in all plots were investigated during field experiments and the controlling efficacy (%) after spraying with TXH09 was calculated. The results showed a good efficacy of TXH09 for pest control and avoidance of leaf damage in field trials. TXH09 EC had good controlling efficacy causing declines in larval populations of L. exigua, P. xylostella and S. litura by 3 days after treatment, and maintaining high efficacy for the next 7–10 days. TXH09 WDG also exhibited a superior controlling effect on P. rapae, C. modinalis, S. inferens and C. suppressalis larvae. Moreover, TXH09 also displayed a considerable protective effect on rice leaf growth, and showed higher controlling efficiency on the insect pests than hexaflumuron at the same active dose. The results indicate that TXH09 as a new prospective insecticide is favorable for the pest management in vegetables and rice.