花绒寄甲与松褐天牛及松材线虫病三者间长效关系研究

The Long Term Relationship Among Dastarcus helophoroides,Monochamus alternatus and Brsaphelenchus xylophilus

利用天敌昆虫开展生物防治是一条优良的、长效的措施,花绒寄甲是控制松褐天牛防治松材线虫病的重要优势天敌。为评价花绒寄甲林间应用效果,于2020—2022年在江西部分疫区开展了“疫木不砍伐或不清除,只释放花绒寄甲”试验,通过对林间松褐天牛种群密度监测、花绒寄甲寄生率及病死树下降率调查,研究了花绒寄甲林间种群增加量、松褐天牛种群下降率与病死树减退率的关系。结果显示:花绒寄甲对松褐天牛的最高寄生率达94.19%,平均寄生率由2020年的13.19%增加到2022年的72.44%,提高5.49倍;病死株数量在前2 a下降不明显,直至第3 a之后,病死树数量才急剧下降,病死树校正减退率平均为68.00%,其中马尾松纯林的校正减退率为72.37%,显著高于松阔混交林的校正减退率(59.26%);松材线虫病的病株率随松褐天牛种群密度降低而降低,呈显著正相关;与防治前(2019年)相比,2022年的松褐天牛种群密度下降58.43%~98.67%,平均下降了89.43%,而花绒寄甲的种群数量却呈现急剧增加,3 a平均上升221.03%,这说明,在疫木不清除条件下,通过3 a的天敌释放,能大幅度提高林间自然花绒寄甲虫口密度,同时显著降低害虫天牛的虫口密度,显著降低松材线虫病的病死树数量,从而达到持续控制松材线虫病的目标。

It is an efficient and long-term measure to use natural enemies to carry out biological control.Dastarcus helophoroides Fairmaire is an important superior natural enemy for controlling Monochamus alternatus to control Bursaphelenchus xylophilus.In order to evaluate the effect of the application of D.helophoroides in the forest,the experiment of“no cutting or clearing of diseased trees,only releasing D.helophoroides”was carried out in some epidemic areas of Jiangxi Province from 2020 to 2022.By monitoring the population density of M.alternatus,investigating the parasitic rate of D.helophoroides and the decline rate of dead trees,the relationship between the increase of the population of D.helophoroides,the decline rate of M.alternatus population and the decline rate of dead trees was studied.The results showed that the highest parasitism rate of D.helophoroides to M.alternatus was 94.19%,and the average parasitism rate increased from 13.19%in 2020 to 72.44%in 2022,5.49 fold increase.The number of dead and diseased trees did not drop significantly in the first two years,but it did not drop sharply until the third year.The average corrected decline rate of dead and diseased trees was 68.00%,of which the corrected decline rate of pure masson pine forest was 72.37%,significantly higher than that of mixed pine and broad-leaved forest(59.26%).The disease rate of pine wood nematode decreased with the decrease of population density of M.alternatus,showing a significant positive correlation.Compared with that before the control(2019),the population density of M.alternatus in 2022 decreased by 58.43%-98.67%,with an average decrease of 89.43%,while the population number of D.helophoroides showed a sharp increase,with an average increase of 221.03%in three years.This indicates s that under this condition the diseased trees are not cleared,the population density of natural D.helophoroides can be greatly increased,the population density of pest longicorn beetles could be significantly reduced,and the number of dead trees affected by pine wood nematode disease could be significantly reduced through the release of natural enemies for 3 years,so as to achieve the goal of continuous control of pine wood nematode disease.