Studies On Control Of Monochamus Alternatus Hope-the Insect Vector Of Bursaphelenchus Xylophilus

Monochamus alternatus Hope, a major hazard to pine forest like Pinus massoniana,P. thunbergii, P. yunnanensis and Cedrus deodara, is an important trunk border insouthern China pine forest, and the most crucial communication media ofBursaphelenchus xylophilus Nickle. In this paper, in order to provide a technical base forthe pest control, Dastarcus helophoroides were used to biologically control Monochamusalternatus Hope, and so it is the thiacloprid. The results shows that:1. According to the two-years indoor observation of D. helophoroides at25℃constant temperature, the new emerged adults begin to lay eggs at the8th days with therelative concentrated peak egg-laying of the day at noon and of the year at May–August.The adults have the consecutive characteristics of laying eggs with2000eggs per mouthat the peak periods. The average lifespan of adults is one year, while the maximumlifespan can reach to two year. The average egg duration is8days, and the averagehatching duration is10days, with the hatching rate is90%. The average duration oflarval stage is10days and the average pupal duration is45days.2. Control the old larva and pupa of M. alternatus Hope using the adults of D.helophoroides. The results showed that the larva reduction rate showed significantdifference after release D. helophoroides adults of different density and time. The larvadropping rate is69.83%on60per tree; and the dropping rate is80.56%on90per tree;and89.85%on180per tree. However, take the economic costs into consideration; theoptimum release density is90per tree. The larva dropping rate is79.81%when thereleasing time is late March; and the dropping rate is51.58%when the releasing time islate April; and73.93%when the releasing time is late August. So, the best releasing timeis late March and August.The larva dropping rate of M. alternatus Hope showed significant difference ofdifferent releasing time of D. helophoroides larva. The dropping rate is37.35%on earlyAugust,77.69%on late September,73.57%on late April. So, late April and lateSeptember is the better choice of releasing time.The dropping density on lure-wood shows a significant difference of differentreleasing density of adult and larva of M. alternatus Hope. The dropping rate is47.93%of30adults and an egg card per1m on the trunk and main branch,71.41%of60adultsand the same egg card,73%of60adults and an egg card per1.5m on the trunk and mainbranch,80.76%of90adults and an egg card per1.5m on the trunk and main branch. So,60adults and an egg card per1.5m on the trunk and main branch is the better choice ofdropping density.3. There are differences in the killing effects of different dilution ratio of2%thiacloprid aqueous capsule suspense. Analyze the poison effects in5days, diluted100times and200times,400times and600times exists significant difference, however,100times and200times doesn’t not exists significant difference. Take the economic cost into consideration,200times of2%thiacloprid aqueous capsule suspense is advised.Feed the poisoned adult at different time after spraying diluted200times of2%thiacloprid aqueous capsule suspense, and evaluation the efficacy duration. The resultsshowed that, this drug is not only very effective, but also persistence that lasted foralmost30days.The number of M. alternatus Hope adult is2.78time to the control after sprayingthe diluted200times of2%thiacloprid aqueous capsule suspense in the prevention andtreatment area. The ratio of larva number on the lure-wood of spraying area and controlis0.3477. The change rate of dead tree in the spraying and control is-77.95%and+57.56%.4. Feeding the M. alternatus Hope adult after Spraying1%thiaclopridmicroencapsulated powder and evaluate the efficacy duration. The results showed that,this drug is not only very effective, but also very persistence that the poison effect reachto65%after30-40days.In2009-2012, after spraying1%thiacloprid microencapsulated powder inexperimental area,236and504,196and741,134and295,107and400adults capturedin each the test and control group. The grooving amount of M. alternatus Hope adult onthe lure-wood in spraying area is52.21,42.5033.23,25.33/m2. And the ratio of sprayingarea and control is0.4804,0.195,0.3712and0.1297. The dropping rate of dead tree inspraying area is73.78%,55.71%,26.24%and25.72%, and the rising rate of dead tree incontrol is11.21%,25.75%,53.18%and57.56%. The relative controlled effect is76.42%,64.78%,51.85%and52.86%. According to the results, the attractiveness of traps issignificantly lower than the control, and the M. alternatus Hope adults are droppingevery year. The dead tree in experimental area is dropping every year, however, the trendin control is otherwise. In conclusion, this drug is very effective.In conclusion, control M. alternatus Hope number and add the D. helophoroidesnumber by using lure-wood and releasing old-larva, mature-larva and pupa at proper time,spraying long efficacy duration, low toxicity, strong effect2%thiacloprid aqueouscapsule suspense and1%thiacloprid microencapsulated powder. Reduce the density of M.alternatus Hope to control pine wood nematode.