Studies On The Biological Characteristics And Control Techniques Of Xylotrechus Rusticus Linnaeus

According to investigation that made in Hongqi forest farm in Daiqing, Heilongjiang Province during the summer of 2003, we found that Xylotrechus rusticus. Linnaeus occurred one generation per year in Heilongjiang province, overwintered as last stage larve in boring tunnel. The larva began to pupate on April 29th and ended on May 15th, pupation entered ascending stage on May 3rf or May 4th and arrived at fastigium three days later, then stepped to descending stage on May 9th or 10th. Equation that can best describe pupation schedule was derived as y = 0.0281 + 0.0302t + 0.0097t2 -0.0005t3. The pupa entered their eclosion stage on May 18th and ended on June 15th, ascending stage of eclosion turned up on May 19th and fastigium emerged three days later, on May 28th eclosion arrived at its descending stage. Equation that can best describe eclosion schedule was derived as y = 2.1966 - 37.7904 t-1. Four days later, the new eclosion longicom bettles began to bite the bark that covered their channels and flew out, this stage continued for about two weeks (from May 22th to June 4th), The ascending stage of the course emerged on May 24th and fastigium arrived three days later, then after anather three days the descending stage appeared. Equation that can best describe this schedule was derived as y = - 4.1224 + 0.2095t-(5.0752E-05)t3.Study on spatial distribution of Xylotrechus rusticus Linnaeus was made, result suggested that larvae in polar plantation belong to negative binomial distribution, and six indices of aggregation revealed that it's of aggregation pattern. Survey of vertical distribution demonstrate that larva are concentrated on polar trunk in range from 1 to 4 meters in the height. An equation describing the attack and height of polar trunk was derived as y = 0.068 + 0.417x-0.136x2 + O.Ollx3. The equation was tested (by correlation coefficient and significance) to be believable.Adult's behavior of Xylotrechus rusticus Linnaeus were partly studied in polar forest, result suggested that the bettles usually copulate for over ten tunes and rest for about 3.95min on average at each interval after they hold together. As long as been disturbed by another more attractile female bettle, the mating male bettle would turn to the newcoming one promptly. Study on oviposition of Xylotrechus rusticus Linnaeus suggested that the female bettles prefer to laying eggs in the morning, each time they lay 21 eggs on average and this take them for about 13minnutes.Result on resistance of poplar to Xylotrechus rusticus Linnaeus suggested that among 23 strains of polar been surveyed in artificial polar woods in northeast region, seven stains were harmed by Xylotrechus rusticus Linnaeus, they are Populus pseudo-simonii Kitag, Populus simonii,populusshuangyangkuai, populus meiqing, Populus pseudo-simonii X black, Canadian polar and populus beijing. Among which, the former four strains were severly harmed(36% to 100% of the poplars been harmed.). Strains as Populus simonii XP. nigra, Populus berolinensis ect(nine in total) were not harmed, among which, only Populus simanii XP.nigra was planted in large areas, so it can be paanted as a resistant strain in other regions of northeastStudy on resistance of mixed forest(MF) to Xylotrechus rusticus Linnaeus indicated that, whether in poplar-pine MF or poplar-poplar MF, less trees were found to be harmed by longjcorn bettles comparing with pure forest(PF). In MF composed of laich-Populus simonii, we found 16% of poplar(27a) harmed, comparing with a ratio of 42% in Populus simonii(same age) PF. Only 8% of poplar(20a) harmed In MF composed of Populus pseudo-simonii Kitag and Pinus sylvestris varmongolica, but we found 36% of poplar harmed in PF of 27a Populus pseudo-simonii Kitag(84% with 35a). In MF composed of Populus simonii and Pinus sylvestris varmongolica, we found 14% of poplar(42a) harmed, comparing with a ratio of 56% in PF of 40a Populus simonii. The above result suggested that to some extend we can control Xylotrechus rusticus Linnaeus by building mixed forests.Three kinds of...