Studies On Non-Pollution Control For Semanotus Bifasciatus Motschulsky (Coleoptera: Cerambycidae)

The longicorn beetle, Semanotus bifasciatus Motschulsky is a main trunk pest of the cypress. And it is the most harmful pest to the weakened pines, standing dead trees and new fallen logs of cypress species, such as Sabina chinensis (Linn) Antoine,Platycladus orientalis (Linn) Franco and Junaperus communis Linn, etc. The phloem and xylem of plant is severely damaged and the conductive tissue is cut off or destroyed. Thereby, it influences water and nutrient transport, makes the light growth vigor weakness and makes the branch and plant heavily damaged dead. Also it seriously threatens greening achievements and the protect of ancient cypress. The mean occurrence area is over 6,700hrn2 in Jinan City each year. According to the survey in 2002, the whole occurrence area was 8,000 hrn2. It not only severely affected the tree growth but also made a large number of trees killed. The direct economic losses was $5,615,000 and has caused incalculable loss on the ecological environment (Xia et al, 2005).If let the pest freely spread, it is bound to make the forest resources heavily destroyed, and cause tremendous impact on ecological protective forest, preventing soil and water loss, water source conservation, windbreak and sand fixation, improving the ecological environment of Spring City and intake of groundwater and spring line spewing. In this article, we carried out research on biological characteristics combing other reference materials in Jinan area and summarize non-pollution measures of this pest.1 Biological Characteristics of S. bifasciatusThe insect has one generation a year in Jinan City, overwintering by adults in pupal chambers in the trunk. The next spring, it comes to be full awaken in the middle ten days of March. The greedily eating period of the larva is between the last ten days period of April and in the middle ten days of May, mainly damaging in the xylem. The larvae overwintered in canal of hadromestome of hosted tree in the last ten days of May. The thriving stage of pupation and emergence is in the first ten days of September and in the middle ten days of October, respectively.2. Non-Pollution Experiment2.1 Forest Management MeasuresThrough branch pruning (one time in June annually), we cut out the dead branches or weak trees in the lower crown and make the bud-cut not hack and crack. We smear paint in the wound. For sanitation cutting and thinning, we should cut down the damaged trees timely. For the weakened pines of dense stand, we take measures of removal from November to the end of February next year. It certainly contributes to the occurrence and harm of S. bifasciatus. The decreased mortality of treated area was higher than those in control area.2.2 Killing this Pest by Log luresWe set a group of log lures in the forest of P. orientalis, 3~4 per group, and bind the top with the plastic rope standing in the forest. Then we spray 8% Cypermethrinâ…¡200 times to the lures. It can effectively snare the adult of S. bifasciatus. After that, we found the danger degree was lower significantly than that of no spraying and the treated area which no lures.2.3 Control Test of Releasing Scleroderma guani Xiao et WuThe reproduction test of S. guani is given first. And in the larvae harm stage, we embark S. guani of one tube (100 adult per tube) that self-reproduced or purchased to one spots which is 20m2. We firstly open cotton plug of the finger-tube. Then we linerfor it in the branch axils. Also, we can paste the finger-tube in the branches and let the wasp self propelled diffusion. For the first year, the parasitization of 1st generation in the forests reached 52.40% one month later. The 2st generation reached 30.5%. The parasitization of 1st generation more than two years is 57.3%. The 2st generation reached 32.4% two month later. The damaged trees rate of the cypress is only 0.5% after 3 years successive release. It brings down about 90% than the one no release.2.4 Control Test of Cypermethrinâ…¡In the full awaken period, spray the suspension concentrate of 1% Cypermethrinâ…¡200 times on the site of the trunks that 2m below. Thus, it can effectively control the damages. The advantages is economical, efficient and easy to spread.3 Non-Pollution Control Measures for Semanotus bifasciatus MotschulskyAccording to the biological characteristics and the result of non-pollution control test of Semanotus bifasciatus Motschulsky and combing other reference data, we have summarized a set of non-pollution control measures including : Strengthening Quarantine Supervision, Forest Management Measures, Snare, Biological Control, Unharmful Chemical Control, etc.