蜡蚧轮枝菌对月季长管蚜的毒力测定

研究结果表明蜡蚧轮枝菌对月季长管蚜有较强的致病性,孢子浓度2.0×105个/mL时可造成大量月季长管蚜感染死亡,其LT50=(6.62±0.14)d;而高浓度2.0×108个/mL对月季长管蚜感染致死的LT50=(4.69±0.16)d,第8天的死亡率达93.6%,致死中时随浓度增加而缩短。第5天的致死中浓度为(1.72±0.18)×107个/mL,第8天为(1.53±0.15)×104个/mL,致死中浓度随时间增加而减小。

非寄主植物对月季长管蚜嗅觉行为的影响

为寻求新的植物源引诱剂和驱避剂,采用"Y"型嗅觉仪测试方法,研究了非寄主植物(韭菜和孔雀草)对月季长管蚜嗅觉行为的影响。结果表明:月季与非寄主植物叶片混合后对月季长管蚜的引诱率均明显低于未与非寄主叶片混合的月季叶片,月季叶片∶孔雀草叶片以1∶3的比例混合后对月季长管蚜驱避效果最好,引诱率仅为20%,比月季叶片低33%。月季叶片∶韭菜叶片以1∶3的比例混合后对月季长管蚜引诱率为26%,比月季叶片低28%。

5种外来入侵植物的茎叶提取物对月季长管蚜的触杀效果实验

采用浸提法，用95％乙醇为溶剂得到紫茎泽兰、薇甘菊、三叶鬼针草、肿柄菊、酢浆草5种外来入侵植物的茎叶提取物。将植物提取物稀释成1、5、10倍液，在室内用微量点滴法，测定其于24h、48h、72h内对月季长管蚜的触杀效果。结果表明，紫茎泽兰和薇甘菊对月季长管蚜的触杀效果明显高于三叶鬼针草、肿柄菊和酢浆草；5种植物提取物的触杀效果在不同浓度梯度上都无显著差异；肿柄菊植物提取物对月季长管蚜的触杀效果在时间上有极显著差异，其他4种的触杀效果在时间上呈显著差异，都在0～24h内触杀效果最好。

附子浸渍液对花卉蚜虫的毒力测定及药效试验

室内毒力测定结果表明,附子浸渍液对观赏园艺植物花卉上常见的桃蚜和月季长管蚜具有较高的毒性,LC50为原液稀释14.99倍和15.07倍。室内药效试验表明,稀释10倍的附子浸渍液对桃蚜和月季长管蚜药后48h校正虫口减退率分别达到85.56%和89.94%,稀释15倍的附子浸渍液对桃蚜和月季长管蚜药后48h校正虫口减退率分别达到79.97%和81.08%。经DMRT于5%水平检验与田间常用化学药剂40%氧乐果乳油1500倍液和45%马拉硫磷乳油1000倍液均无显著差异。

Alternaria toxin-induced resistance against rose aphids and olfactory response of aphids to toxin-induced volatiles of rose plants

The search for active toxins for managing weeds or plant diseases is believed to be a promising avenue of investigation.However,the effects of Alternaria toxins on insects have just begun to be investigated.Bioactivities of toxins from four strains of Alternaria alternata on Rosa chinensis and rose aphid Macrosiphum rosivorum were tested in the present study.At a concentration of 50.0μg/ml,the crude extract(toxin)of strain 7484 was found not to be harmful to rose plants with excised leaf-puncture method(P≥0.079),and rose plants showed enhanced resistance to rose aphids when this Alternaria toxin was sprayed on the plants(P≤0.001).However,this toxin caused no detrimental effects on aphids in insecticidal bioassay at a concentration of 10.0 to 160.0μg/ml(P≥0.096).Therefore,the Alternaria toxin had significantly induced the resistance of rose plants against rose aphids,demonstrating that the resistance mechanism triggered by the Alternaria toxin in the rose plant may also be used by the plant to defend itself against insects.Further bioassays aimed to discover the olfactory responses of aphids to the toxin-induced volatiles of host plants.The aphids were significantly more attracted to both volatiles emitted and collected from control rose plants than to both volatiles emitted and collected from the toxin-treated rose plants(P≤0.014).This result showed that the toxin-induced resistance related to the volatile changes of host plants.

链格孢菌毒素能诱导中国月季产生抗蚜活性的细交链孢菌酮酸（英文）

目的:研究链格孢菌毒素能诱导中国月季植株产生对月季长管蚜的抗性,从而证实寄主植物介导的病虫互作关系的存在,并研究其互作机制。创新点:证实了一种对寄主植物和害虫均无毒性的真菌毒素能使寄主植物产生对昆虫的诱导抗性。方法:马铃薯葡萄糖琼脂(PDA)培养基培养链格孢菌获得毒素粗品,大孔树脂纯化后配制成不同浓度的溶液,喷施到中国月季植株上。处理结束后接种月季长管蚜,与对照相比,计算毒素处理对蚜虫的抑制百分数。用高效液相色谱法(HPLC)结合标准品分析毒素中是否存在细交链孢菌酮酸(TeA),并测定其含量。TeA同法处理中国月季植株,测定TeA对蚜虫的抑制率,并与毒素粗品比较。再通过HPLC法测定植物体表和体内残留的TeA,以证明TeA能自然降解完全。结论:(1)链格孢菌粗毒素和对照品TeA均能使中国月季植株产生对月季长管蚜的系统诱导抗性,显著降低月季长管蚜对中国月季的危害;(2)链格孢菌粗毒素中的主要抗蚜活性成分是TeA,TeA有望成为中国月季上具有抗蚜活性的先导化合物;(3)粗毒素和对照品TeA对蚜虫和植物均无伤害作用,但能激活植物对虫害的诱导抗性(ISR)和系统获得性抗性(SAR),可直接证实二者间存在着寄主植物介导的间接的病虫互作关系。