USDA-ARS Southeastern Fruit and Tree Nut Research Laboratory, 21 Dunbar Rd., Byron, GA 31008, USA.
J Econ Entomol. 2011 Feb;104(1):47-53. doi: 10.1603/ec10137.
The lesser peachtree borer, Synanthedon pictipes (Grote & Robinson) (Lepidoptera: Sesiidae), is indigenous to eastern North America. It is a pest of commercially grown Prunus spp., especially to southeastern peach orchards where earlier regulatory changes affected pesticide use on peach leading to increased S. pictipes damage. Pest management practices are now having a positive effect toward control of this pest, but cost-competitive biological control solutions that promote environmental stewardship are needed. Here, we tested four Steinernema species and five Heterorhabditis species of entomopathogenic nematodes against larval S. pictipes. Included were four strains of S. carpocapsae (All, DD136, Sal, and Hybrid2) and three strains of S. riobrave (3-8b, 7-12, and 355). Larvae treated with any strain of S. carpocapsae always resulted in <20% survival, whereas larval survival was always >50% when treated with any other Steinernema or Heterorhabditis spp. These differences were always significant for the Hybrid2 strain of S. carpocapsae and similarly for other tested S. carpocapsae strains except for when larvae were treated with the 3-8b strain of S. riobrave. In addition, we determined the susceptibility of different size S. pictipes larvae, because they occur simultaneously in orchards, and we found that larvae rated as "medium" and "large" were significantly more susceptible than "small" larvae. Last, we demonstrated that moisture-retaining covers (placed over S. pictipes-infested wounds on peach limbs) increased efficacy of nematode treatments against larval S. pictipes. Even when using highly virulent nematodes against S. pictipes, it is likely that an aboveground application will require an environmental modification to remain efficacious.
小型桃蛀果蛾，Synanthedon pictipes（Grote & Robinson）（鳞翅目：卷蛾科），原产于北美洲东部。它是商业种植的李属植物，特别是东南桃果园的害虫，那里早期的监管变化影响了桃树上的农药使用，导致小型桃蛀果蛾的损害增加。害虫管理措施现在对控制这种害虫产生了积极的影响，但需要具有成本竞争力的促进环境保护的生物控制解决方案。在这里，我们测试了四种斯氏线虫属和五种异小杆线虫属的昆虫病原线虫对幼虫小型桃蛀果蛾的作用。包括四种斯氏线虫属的菌株（All、DD136、Sal 和 Hybrid2）和三种异小杆线虫属的菌株（3-8b、7-12 和 355）。用任何一种斯氏线虫属菌株处理的幼虫，其存活率总是<20%，而用任何其他斯氏线虫属或异小杆线虫属菌株处理的幼虫，其存活率总是>50%。这些差异对于斯氏线虫属的 Hybrid2 菌株总是显著的，对于其他测试的斯氏线虫属菌株也是如此，除了当幼虫用 3-8b 菌株的异小杆线虫属处理时。此外，我们确定了不同大小的小型桃蛀果蛾幼虫的易感性，因为它们同时出现在果园中，我们发现被评为“中”和“大”的幼虫比“小”幼虫明显更容易受到感染。最后，我们证明了保湿覆盖物（放置在桃树枝条上受小型桃蛀果蛾感染的伤口上）可以提高线虫处理对幼虫小型桃蛀果蛾的效果。即使使用对小型桃蛀果蛾高度有效的线虫，在地上进行处理也可能需要进行环境改造才能保持有效。
