| Pine wood nematode disease is a fatal factor that causes the death of a variety of pine trees.Its main vector is Monochamus alternatus Hope,which is widely distributed in East Asia(21 provinces and regions in China),which has become the main factor driving the rapid spread,spread and outbreak of pine wood nematode disease.Therefore,reducing the occurrence of pine wood nematode disease by controlling the number of M.alternatus has become one of the important ways of prevention and control.However,how to effectively reduce the population of M.alternatus is still facing many challenges.At present,measures such as the release of natural enemies,the removal of dead trees,and the trapping of adult insects have been used in the frontline control of beetles,and the forest aircraft spraying control M.alternatus has also been rapidly emerging in recent years,and has now been adopted in 27 cities in each province.Compared with traditional methods,aircraft spraying control has obvious advantages in large-area operations and operational efficiency,but still faces many problems and challenges:(1)The evaluation of aircraft spraying control effects varies from place to place,and there is a lack of standards;(2)Aircraft spraying control due to various factors,some current standards still use the field of agricultural aircraft spraying control,which differs greatly from the forest aircraft spraying control;(3)Commercial aircraft spraying control only focuses on short-term effects,but whether the effect can continue into the next year or the next year or more Long-term(long-term effects)are still highly questioned.To this end,this study discusses the actual performance of flying anti-spray through the case analysis method of M.alternatus aircraft spraying control operation;through the simulation test of drone spray,the effect of some factors on drift in aircraft spraying control operation is studied;At the same time,the direct lethal effect and the indirect lethal effect of pesticides on M.alternatus adults were studied in the forest areas that had been aircraft sprayed;The number of changes in the short-term and long-term aircraft spraying control and other content.The conclusions of the study are as follows:(1)The number of droplets and droplets on the test card for NCXS is relatively high,but the receiving amount on a single card differs greatly;The per uint area is 5.17 drops,and the second aircraft spraying per uint area is 3.27 drops.The frequency distribution is similar to that of a single card.The amount of fog droplets per unit area averaged 5.17 drops for the first flight and 3.27 drops for the second flight.Fog droplet coverage rate in Le’an operation area> 5%,unit droplet volume> 5 droplets,average droplet size is 0.8-1.5cm2;crown fog droplet coverage and unit droplet volume of the second flight prevention are higher than the trunk Under the tree,but the value of the canopy for the first flight is lower than the trunk and under the tree;on the four directions of the southeast,northwest,the distribution of pesticide droplets has certain fluctuations,the distribution of droplet frequency is different,non-parametric test The results show that the difference between the number of droplets in the east flight line of the first flight defense and the other directions is significant,but the difference between other directions is not significant;the difference between the east flight line and the south flight line of the second flight defense is significant,the difference from the west and north directions is not significant,the south direction is significantly different from the west and north directions,the west direction and the north direction are also significantly different,in addition,the difference between the first and second flight defenses in the same direction is not significantly.(2)UAV spray simulation test results: the flight height and flight speed of the aircraft will have a significant impact on the droplet coverage.With the increase of the flight height and flight speed,the droplet density gradually decreases,and the presence of lateral wind makes the The fog droplets are obviously drifting and the interaction with flight height and speed is significant;the canopy density in the forest area has obvious trapping effect on the fog droplets,and the addition of settling agents can increase the coverage of the fog droplets to a certain extent.(3)The lethal effect of fly control on M.alternatus: On the direct lethal effect,the mortality rate of adult M.alternatus in the experimental group 1-2 days after the flight control in NCXS case reached more than 70%,and all deaths occurred within 2-4 days,And the control group survived for 6 days;indirect effect,the survival rate of M.alternatus after spraying pine branches 3 days before NCXS case feeding was slightly lower than that of control group,and after spraying pine branches 4 days after feeding The survival rate of M.alternatus was slightly higher than that of the control group.In LA cases,the feeding of M.alternatus died within 1 d.The experimental group all died within 1 d.The control group survived for more than a week.(4)Population changes of M.alternatus populations during the year of flight control:There was no significant difference in the populations of M.alternatus populations between the pilot area before the flight control and the control group,and there was no difference between the outside forest populations of group A and the control one week after the aircraft spraying control The overall population of cattle,other groups outside the forest,forest margin,and forest population are significantly different from the control group,and the control effect reaches 50%-80%.(5)Long-term effect of aircraft spraying control: The population of M.alternatus in the one-year aircraft spray area of Nanchang is generally higher than that of the control group and has rebounded from last year.The results on the three gradients outside the forest,forest edge and forest are similar.There was a significant difference in the number of occurrences in the test area and the control area during the Shengfa period.The number of dead masson pine on the plots and lines in the aircraft spraying control test area showed a decreasing trend between 2016 and 2018,and increased in 2019;Lushan Mountain multi-year aircraft spraying control area in 2019 both the M.alternatus population and the control group have two peak periods,the trend is basically the same,the difference is more scattered than the one-year aircraft spraying control zone,the growth of the dead masson pine in the aircraft spraying control zone has decreased from 2017 to 2018,and the control group is basically the same.In 2019,the number of dead trees in the aircraft spraying control zone increased slightly,while the control zone declined. |
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