Dynamic Analysis Of Rice Pests In Jixi County

Based on the 2005-2016 year forecast data of rice insect pests in Jixi County,the species of rice pests in Jixi county were preliminarily defined.Combined with the field survey data of rice pests in Jixi County,the occurrence of major rice pests in Jixi county was studied,and the occurrence regularity of rice planthopper(Laodelphax striatellus,Sogatella furcifera,Nilaparvata lugens was analysed.The main results listed as below.1.Species of rice pests in Jixi CountyThrough the investigation of pests in rice field,26 kinds of rice pests were found in Jixi County,which belonged to 6 orders,13 family.Nilaparvata lugens,Sogatella furcifera,Cnaphalocrocis medinalis,Chilo suppressalis were main pests in rice field.Scirpophaga incertulas,Sesamia inferens,Parnara guttatus,Laodelphax striatellus,and Thrips oryzae,Haplothrips aculeatus were forecast and monitoring objects of rice paddy field,but Naranga aenesc,Nephotettix cincticeps,Deltocephalus dorsalis were occasional pest of rice paddy field.The main rice pests in Jixi county were in the period of rice tillering stage,booting stage and filling stage.2.Occurrence of rice planthopper in Jixi CountyLight trap of rice planthopper showed that,the amount fluctuation of rice planthopper in different years of 2005-2016 were large.From May to September,L.striatellus,S.furcifera,N.lugens appeared successively,and the tillering stage(May),from the tillering stage to the booting stage(6-7 months),from the heading stage to the grain filling stage(8-9 months)of rice was damaged inrespectively.The main forth(2)generation of rice planthopper was Sfurcifera,and the main fifth(3)generation of rice planthopper was S.furcifera and N.lugens,which the main sixth(4)generation of rice planthopper was N.lugens.Field investigation of rice planthopper showed that,the amount fluctuation of rice planthopper in different years of 2005-2016 were large,but the amount decreased after 2014.The amount in the rice tillering stage of rice planthopper were lower than the amount at booting and filling stage in 2005-2013,but 2014-2016 on the other hand.3.Occurrence of Cnaphalocrocis medinalis in Jixi CountyThe results of C.medinalis were basically consistent between light trap and field investigation.The amount of C.medinalis was relatively high in 2006-2008 years,and the amount declined significantly after 2009,but the amount was low after 2014.The amount fluctuation of C.medinalis at the same year in different growth stages of rice plants were large.The four(2)and five(3)and six(4)generation C.medinalis outbreak were possible,but the amount mostly reached the maximum in rice booting stage larvae.4.Occurrence of Chilo suppressalis in Jixi CountyThe results of C.suppressalis were basically consistent between light trap and field investigation in 2005-2016.In different years,the amount of C.suppressalis increased first and then decreased,and the amount were higher in 2011-2013,and reached the maximum in 2012,and decreased after 2014.In the most years,the first generation of C.suppressalis in rice tillering stage damaged heaviest.Its larvae caused rice sheath and withered heart,which seriously harmed the normal growth of nce.5.After 2014,the population of the main pests on rice in jixi County decreased dramatically,and the overall damage also declined obviously.