云杉矮槲寄生开花特性及化学防控

Flowering Characteristics and Chemical Control of the Buds of Arceuthobium sichuanense

云杉矮槲寄生是严重危害三江源地区天然云杉林的多年生寄生性种子植物。对云杉矮槲寄生开花动态的定点监测结果表明:云杉矮槲寄生花期持续40天以上,单株花序寿命约为15天;雌花在花期结束后6～8天后开始坐果,幼果初期无果梗,浅绿色,直径约为1～1.3mm;果实成熟后期,果梗逐渐伸长至1～1.5mm,颜色转为深绿色。4种不同浓度的植物激素类药剂[40%乙烯利水剂,50%国光丁酰肼可溶性粉剂,20%国光萘乙酸粉剂(NAA)和90.8%脱落酸(ABA)]对云杉矮槲寄生花芽的药剂防治试验发现:1∶400的40%乙烯利水剂为防除效果最佳,可达100%,且未对云杉植株产生不良药害反应。

Arceuthobium sichuanense is the most important vascular parasite on Picea crassifolia,Picea purpurea,Picea likiangensis var. balfouriana and Picea spinulosa in Sichuan,Qinghai and Tibet,and has severely damaged forest stands by dispersing explosive fruits in August and September in Sanjiangyuan area of Qinghai Province. A. sichuanense affects host growth through the interaction of the host with the mistletoe endophytic system,and expropriates water,minerals,and carbohydrates from the host,causes deformation of the infected stem,increases susceptibility to other disease agents or insect pests,and reduced the host longevity. To select the best measure for control of A. sichuanense flowering buds in its early days and the flowering dynamics were investigated in its initial flowering phase （in the middle of May）. The results showed that the flowering span of A. sichuanense populations was more than 40 days,while individual parasite was flowering for around 15 days. Greenish fruits emerged in 6 -8 days after the flowering span,and the fruit pedicel elongated to 1 -1. 5 mm in its explosive span. Meanwhile,four kinds of plant hormones including 40% ethephon aqueous solution,50% daminozide water solution powder,20% 1-naphthylacetic acid dust and 90. 8% abscisic acid were applied to the flowering buds of A. sichuanense. The results showed that all diluted 40% ethephon（diluted 100,200 and 400 fold） killed the flowering buds successfully and the mortality of flowering buds reached nearly 100%. The dilution of 1∶ 400 was the best choice because it was harmless to spruce needles and branches. Although the other three kinds of plant hormones also had relative effects,they were not suitable for epidemic prevention in large areas in regard of the cost and ecological concerns.