| Bemisia tabaci(Gennadius)is a composite species composed of various biotypes which are difficult to distinguish,since nineteenth Century,it has brought huge losses to all parts of the world.In recent years,Q type Bemisia tabaci in Bemisia tabaci is characterized by its insensitivity to low temperature and its strong tolerance to drugs in Yanan,the harm to tobacco is more and more serious,especially for Yichuan tobacco area.In this study,Bemisia tabaci in Yanan area Q which is a serious hazard of Yichuan Yingwang Yichuan County of the village Beidi,five point sampling method/PCR amplification method/microscopic observation method and so on,the biotype life table of natural population/overwintering/occurrence and migration rule/occurrence law of occurrence/spatial distribution/vertical distribution/preventive measures and so on have been studied.The effective way and reasonable method for the ecological control of Q type Bemisia tabaci were put forward.In practice,it is of great significance to control the large occurrence of Q type Bemisia tabaci,reduce the economic loss,and guide the construction and production of the base.The results for the prevention and control,field investigation and estimation of damage loss of Bemisia tabaci have extensive application and reference value,it is of great significance to improve the income of farmers and the improvement of the ecological environment.The main results are as follows:1.Study on biotype of Q type Q Bemisia tabaci in Yichuan tobacco areaUsing mtDNACOI gene sequencing method to detect biological Yichuan tobacco Bemisia tabaci,the obtained sequence is compared to the BLAST on the NCBI website,the homology analysis results showed that Yichuan tobacco Bemisia tabaci occurred is biotype Q.2.The overwintering and migration of Bemisia tabaci Q in Yichuan tobacco growing areaFive point sampling method was used to investigate the Q type Bemisia tabaci in Yichuan tobacco area,The result shows that,because the outdoor temperature is too low in winter,the Q type Bemisia tabaci can only be overwintered in Greenhouse,it is difficult to overwintering in the soil and in the outdoor.The survey results of the migration rule show that: The migration took place in the second year of April,the average temperature is kept at 12?,a small number of Q type Bemisia tabaci migrated through the greenhouse vent to the nearby tobacco breeded.Type Q Bemisia tabaci began to break out during the greenhouse film exposure in late May to early June,the propagation speed of Q type Bemisia tabaci was further accelerated with the increase of temperature,in mid August,the Q type of Bemisia tabaci reached the peak of one year,from late September to early October,Q type Bemisia tabaci was moved back to the greenhouse.The time of the Q type Bemisia tabaci in the wild is from summer to late autumn,from the late to mid October.And then the plants that migrate to the greenhouse continue to harm,it was not until the second spring to return to the field.3.The influence of main meteorological factors on the occurrence of Bemisia tabaci Q in Yichuan tobacco growing areaPrediction of the occurrence quantity of Q type Bemisia tabaci in tobacco growth period,so as to prevent and control the Q type tobacco Bemisia tabaci in time,the loss can be reduced.According to the meteorological data and survey data of 2006-2016,the main meteorological factor of screening the influence of the occurrence of Q type Bemisia tabaci in the growth period of tobacco is average temperature,average rainfall and relative temperature,and fuzzy matrix was established.The prediction effect of the fuzzy matrix is tested by the meteorological data and the survey data of 2017 as the standard.The level of Q type Bemisia tabaci predicted according to predicted by the fuzzy matrix is in line with the level of Q type Bemisia tabaci occurrence in previous years and is in line with the actual level of Bemisia tabaci in 2017.The application of fuzzy matrix can predict the occurrence of Q type Bemisia tabaci successfully,and it has good prediction effect and simple and convenient,it provides scientific basis for timelyprevention and control of Q type tobacco Bemisia tabaci.4.Study on life table of Q type tobacco Bemisia tabaci populations in YichuanThe population of Q type Bemisia tabaci is divided into the egg,young nymphs,nymphs and adults,4 stages according to its growth and development sequence,the action factors of each stage were divided into relatively independent states,and the natural life table of Q Bemisia tabaci was studied.By investigating the natural population system of Yichuan tobacco Q biotype Bemisia tabaci and feeding the experimental population in the laboratory,the natural population life table of Q Bemisia tabaci on tobacco was established by action factors.Research shows,the value of natural Q Bemisia tabaci population trend index(I)is 28.22,indicating that the next generation of population number will be 28.22 times that of contemporary population number,and the survival rate of the generation is 11%.5.Study on spatial distribution patterns and vertical distribution patterns of Q Bemisia tabaci in Yichuan tobacco areaThe number of Q Bemisia tabaci at all stages was investigated every seven days by seven point sampling method,use of diffusion index,Taylor's power law and Lwao m*-regression method to count the amount of the collection.The results show that: The regression equation of Taylor power law is as follows: lgS2=1.25 lg+0.617;The regression equation of Lwao is as follows: m*-: m* =1.132+1.608,the spatial distribution pattern of Q type Bemisia tabaci was negative two distribution,mainly in the upper part of the tobacco,the spatial pattern of Yichuan tobacco area Q Bemisia tabaci is based on the individual group as the basic component aggregated distribution,the greater the density,the greater the degree of aggregation.6.Study on prevention measures of Yichuan tobacco Q biotype Bemisia tabaciThe virulence experiment of selecting 6 kinds of agents shows that: 10% pipryl ether +25% thiazide +10% allidiamines,0.6% Azadirachtin,1.8% Abamectin three kinds of reagents have good control effect.Conclusion:Yichuan tobacco biotype Q Bemisia tabaci outbreak in August,it is suggested that a 1.8% microbial source of abamectin should be used by August and 0.6% Azadirachtin reagents from pure plant sources carryout prevention and cure. |
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