Study On Occurrence Regularity And Control Of Important Pests On Chrysanthemum Morifolium In Zhejiang

The Chrysanthemum morifolium is the most traditional Chinese herbal medicine with regional characteristics in Zhejiang Province,which is one of the famous region drug“Zhejiang Bawei”.It is mainly distributed in Tongxiang,Haining,Xiuzhou,Yuhang and other places of Zhejiang Province.The C.morifolium is harmed seriously by insect pests,the C.morifolium is inner viscosity Chinese herbal medicine,the pesticide residue of it has a great influence on people,and the study of the happen and control of insect pests on C.morifolium are very few.The article is based on the investigation of C.morifolium pests in Zhejiang Province,and systematic investigation of the occurrence of Aphis gossypii Glover and other important pests.To study the effect of temperature on the survival and reproductive of A.gossypii and Aphis citricola Vander Goot,the laboratory population life tables were built,and then the biological characteristics of experimental population were studied,at last,tested the toxicity of insecticides for the A.gossypii.The main results are as follows:1.The main insect pests in Zhejiang were to A.gossypii,A.citricola,Bemisia tabaci?Gennadius?,Spodoptera litura?Fabricius?,Spodoptera exigua Hübner,Hymenia recurvalis?Fabricius?,Eysacoris guttiger?Thunb.?,Apolygus lucor?m?Meyer-Dur.?,Geometridae,Tingidae,Coreidae,Thripoidea,Cicadellidea,Gryllidae,Locustoidea and so on.The C.morifolium is the main harm of A.gossypii,A.citricola has not been reported before.2.The A.gossypii has two times immigrated on C.morifolium a year.The first occurrence of A.gossypii on March 18th,the number peaked on April 8th.The total number of aphids on one hundred leaves was 820.The second time of A.gossypii occurrence in middle and late August.The fluctuation of quantity is not obvious.Tingidae,B.tabaci,and A.lucor?m mainly do harm to C.morifolium in the second half of the year.3.The optimum temperature for the development of A.citricola was 20?,the optimum temperature for the development of A.gossypii was 25?.The highest intrinsic growth rate of A.citricola is 0.051.The highest intrinsic growth rate of A.gossypii is 0.267.The shortest doubling time for population of A.citricola is 13.6 days;the shortest doubling time for population of A.gossypii is 2.592 days.The nymph of A.citricola and A.gossypii could not developed normally at 30?.The nymph of A.citricola also could not developed normally at 10?.When the temperature is 15?and 25?,the population reached 50 percent of mortality of A.citricola need time shorter than A.gossypii Glover.At 20?,the time needed for the two species of aphid population to reach 50 percent of mortality was basically the same.4.The toxicity of spirotetramat and pymetrozine on A.gossypii were determined with leaf dipping method.The results show that the LC₅₀ of pymetrozine was 34.318mg/L after 48h.It need take more time to play a pesticide effect of spirotetramat.The effect of spirotetramat on aphid slower than nymphs.The LC₅₀0 of nymphs were 66.958mg/L,17.919mg/L and 7.958mg/L after 48h,72h and96h respectively.The effect of 96h on the aphid formation was not obvious,and LC₅₀ was116.935mg/L after 96h,and the mortality began to increase gradually.