| Rice leaf folder,Cnaphalocrocis medinalis(Guenee)is one of the notorious pests of rice.To investigate the occurrence dynamics of Rice leaf folder in Suyu area,statistical data concerning Cnaphalocrocis medinalis collected from 2003 to 2018 and in 1998 were systematically analyzed and the control effect of several kinds of insecticides against this pest was evaluated.The results are present as follows:1.The years where Cnaphalocrocis medinalis outbroke share the similarities with earlier immigration of moth population,more peaks of moth population and larger moth population.For the years before 2012,the fifth(3)rice leaf folder was the predominant generation contributing to damage in Suyu area,however,after that,the adoption of machine-transplanted rice by large plantation families and the increased proportion of late-sowing rice as well as the desynchronized growth period of rice allow the sixth(4)generation of rice leaf folder left to be primary devastating generation.2.The field control effects of bisamides bishydrazide,abamectin,indoxacarb insecticides on rice leaf folder were evaluated.Fourteen days post application,the leaf preservation effects of 35%chlorobenzamide WG,24%methoxyfenazide SC,12%methylene fluoramide ME,10%Methylene dimethoate SC and 60%Emamectin benzoate monosultap WP were 92.27%,91.87%,91.08%,91.08%and 78.5%respectively.After 14 days,the insecticidal effects of these chemicals were 95.2%,94.42%,95.42%,90.48%and 75.92%respectively.Additionally,the leaf preservation effects of 12%abamectin·indenacarb WP,15%indenacarb SC,10 billion spores/ml empedobacter brevis SC,5.0%emamectin benzoate SC were 81.04%-86.48%and the insecticidal effect was 82.68%-87.31%.These results strongly suggested the rotation utilization of methoxyfenozide,bisamides,macrolides antibiotics,indoxacarb and mixtures of different agents for C.medinalis management in paddy field. |
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