| Pine wilt disease,also known as wilt disease,is a contagious and catastrophic disease.Once a pine tree is infected with the pine wood nematode(Bursapherenchus xylophophilus),the time to death is only about 40 days,and it can destroy the entire pine forest in 2-3 years,leading to a large-scale reduction in yield and devastating damage to forestry resources,involving more than 50 species of pine species such as Pinus massoniana,black pine,and red pine.Not only has it seriously endangered China’s forest ecological security,but it has also caused serious losses to China’s forest ecosystem and economy.In order to effectively prevent and control pine wilt disease and ensure ecological environment safety,this study takes Bursaphelenchus xylophilus and Monochamus alternatus as the research objects,and uses drone spraying as the research method.By studying the life history and emergence patterns of Monochamus alternatus,we further understand and predict the occurrence dynamics of Monochamus alternatus adults,and choose to carry out drone spraying to prevent and control pine wilt disease during the optimal control period,Effectively reducing the population density and controlling the spread range of pine sawfly beetles,cutting off the transmission chain of pine wilt disease can achieve the goal of controlling the occurrence and spread of pine wilt disease,and providing theoretical and technical support for the healthy management of pine forests.Using Yao Township,Huilongshan,Zixing City,Chenzhou City,Hunan Province,as the research are,the effect of drone spraying on controllingpine wilt disease was studied using a fixed-point survey method.The control effect was expressed as the reduction rate of Monochamus alternatus population,the reduction rate of Bursaphelenchus xylophilus,and the reduction rate of dead pine wood removal.The main conclusions of the study are as follows:(1)A study on the life history and adult emergence patterns of the Monochamus alternatus.Through indoor breeding methods,it can be seen that the Monochamus alternatus has one generation in the Yao ethnic village of Huilongshan in the past year.The larvae overwinter in the pine trees,and begin to move in late March of the following year.They pupate in mid April and emerge as adults in early May.The adult activity period is from May to September,with a peak period from June to July.Based on the study of the life history and adult emergence patterns of the Monochamus alternatus,it is possible to predict the start time of each insect state,determine the start time,peak time,and end time of emergence,and provide a basis for future drone spraying prevention and control.(2)The effect of drone spraying prevention and control on the population density of the Monochamus alternatus.In the forest trapping experiment,the decline rate of the captured Monochamus alternatus in 2020 was greater than that in 2021 and 2022.In 2020,there was a significant difference in the number of pine black beetles between the experimental and control plots.The reduction rate of the insect population in the experimental plot was 69.33%,while the reduction rate in the control plot was-26.92%.The number of pine black beetles in the experimental plot significantly decreased,indicating that drone spraying can effectively reduce the population density of pine black beetles,reduce the natural transmission rate of Bursaphelenchus xylophilus,and effectively curb the further occurrence and spread of pine wilt disease.(3)A study on the effect of drone spraying on the carrying capacity of Bursaphelenchus xylophilus.In the indoor mirror inspection test,the reduction rate of ground worms in the test sample in 2020 was 98.24%,and the reduction rate of ground worms in the control sample was-5.53%.The reduction rate of ground worms in the test sample was significantly higher than that in the control sample.Spraying 8%cypermethrin microcapsules with 300-fold,400-fold,and 500-fold diluents showed control effects on the Monochamus alternatus,with nematode reduction rates of 97.01%,99.71%,and 97.99%,respectively.There was no significant difference in the carrying amount of nematodes between the three treatment plots before prevention and control,and there was a significant difference in the carrying amount of nematodes between water and the control plots after prevention and control.In terms of prevention and control effects,400 times the dilution has the best prevention and control effect,followed by 500 times the dilution,and 300 times the dilution has the worst prevention and control effect.(4)The impact of drone spraying on dead pine trees.According to the analysis of variance on the number of dead pine trees removed from the two villages from 2019 to 2021,there was no significant difference between the number of dead pine trees removed from Baishu Village and the number of dead pine trees removed from Maoping Village.The number of dead pine trees removed from the experimental plot was smaller than that of the control plot,and there was a significant difference between the two.It indicates that conducting drone spraying control can reduce the number of Monochamus alternatus;carrying Bursaphelenchus xylophilus,reduce the susceptibility rate of pine trees,reduce the number of pine tree deaths in the forest,and slow down the spread of pine wilt disease. |
