The Control Indicators And Early Warning Model Of Aphis Glycines In Harbin

This thesis mainly studies soybean aphid,Aphis glycines,as a major pest of soybean,which can cause severe soybean yield loss when the occurrence number of A.glycines is heavy.Therefore,the state has paid great attention to the control of A.glycines.After two years of field investigation in Harbin Xiangyang Farm,community trials and data processing,the research has deeply understood the population dynamics of A.glycines,scientifically predicted the population dynamics of A.glycines,measured the economic threshold,and constructed an early warning model.It provides a more reasonable factual basis for the future green comprehensive governance of A.glycines,and the following results are obtained.（1）The population dynamics of A.glycines in 2018 and 2019 were obtained through two years of field surveys.The field population dynamics of A.glyciness in 2018 to 2019 are mainly affected by temperature.The initial period was mid-to-late June,and A.glyciness occurs in the field.The peak period was also the rampant period of the field from late July to mid-to-late August.The number of population in the field was large.In 2018,the number of aphids reached the peak in late August and almost disappeared in late September.Due to the high temperature and rainfall in 2019,the aphids amount reached the peak in early August,which proves that there will be a certain advance in the receding period from mid-to-late August,and A.glyciness would basically disappear in the field at the end of September.Combined with the analysis of meteorological data,it could be understood that the aphids of A.glycines were mainly related to temperature.（2）The daily economic threshold of A.glycines accumulated aphid and the economic threshold of plant aphid amount were determined through two-year field plot test.Study on the economic threshold of A.glycines,used the community test to control the accumulated aphid number to determine the economic threshold,inoculated the A.glycines artificially before the A.glycines colonizes the soybean,set up 6 groups of treatment,1 group of control,repeat 3 times.Survied recorded the number of aphids per plant and the percentage of soybean yield after harvest every six to seven days,analyzed the relevant data to obtain the cumulative aphid day（The sum of A.glyciness population per plant of every seven days survey）,which was the economic threshold for A.glycines control.Among them,the cumulative aphid day was 2236 heads per day,and the economic threshold for the number of plant aphids（average aphids per hundred plants）was 342 per plant.Combining the analysis of the growth rate and discrete growth rate of A.glycines in the field,the time from the emergence of the aphid to the economic threshold was 33 days.（3）The early warning model of A.glycines was constructed by using SPSS after years of accumulation of dynamic data of A.glycines population in the field.This paper used 2018-2019 data,drew on the 2011-2014 and 2017 data of the degree of occurrence of A.glycines in each survey cycle,and multiple meteorological factor data,used SPSS for single factor correlation analysis to screen out significant correlations model factors,consult relevant literature to determine the selected model factors have biological significance,using multiple linear regression statistical analysis method to construct an early warning model that can predict the occurrence of A.glycines in the field Y=0.12X₁–0.083X₂–0.15X₃+1.866（Y is the occurrence grade of A.glycines;X₁ is the lowest temperature;X₂ is the average temperature,X₃ is the average wind speed）and tested（historical retrospective test,independent sample prediction test）.The results of historical regression test showed that the predicted value was in complete agreement with the actual value with53.98%,and almost the same with 44.44%.Independent sample prediction test results:completely consistent 50%,basically consistent 30%.In gene ral,the forecast has a high accuracy,and it has a great effect on the green comprehensive management of A.glycines in the field,which can be actually used in field control.