Philip Michael M, Orr David B
Department of Entomology, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC 27695-7613, USA.
J Econ Entomol. 2008 Apr;101(2):421-9. doi: 10.1603/0022-0493(2008)101[421:ocfaot]2.0.co;2.
Studies were performed to assess the operational feasibility of Trichogramma exiguum Pinto & Platner (Hymenoptera: Trichogrammatidae) augmentation for suppression of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock) (Lepidoptera: Tortricidae), in commercial loblolly pine, Pinus taeda L., plantations. Single inundative releases containing two cohorts of encapsulated T. exiguum at a potential rate of 224,200 +/- 27,600 females per ha per cohort were made into two 4-ha plots during the second R. frustrana generation in 2000. Augmentation failed to increase parasitism rates above those occurring naturally; yet, 10% fewer shoots were attacked by R. frustrana, but not below acceptable levels. Quality control data suggest that low emergence levels and intense predation by ants upon developing T. exiguum lowered actual release rates to 13,000 +/- 900 females per ha per cohort. The effect of capsule distribution and microclimate on the discovery of capsules by predators (indicated by some E. kuehniella egg removal), parasitoid predation (percentage of eggs removed or destroyed), and subsequent parasitoid emergence was investigated. Uniformly distributed capsules experienced significantly higher predation levels than clustered capsules, and capsules exposed to field conditions for 5 d experienced higher predation than those exposed for 3 d, independently of distribution. Discovery of capsules by predators was unaffected by distribution or exposure period. Microhabitat significantly impacted average maximum daily temperature, the number of consecutive hours per day at or above 35 degrees C, and parasitoid emergence percentages. Parasitoid emergence declined significantly in response to increasing number of consecutive hours per day above 35 degrees C. Microclimate did not impact capsule discovery by predators or predation levels. Augmentation of T. exiguum for suppression of R. frustrana damage may not be practical within P. taeda plantations.
开展了多项研究，以评估在商业火炬松（Pinus taeda L.）种植园中，通过释放微小赤眼蜂（Trichogramma exiguum Pinto & Platner，膜翅目：赤眼蜂科）来抑制楠塔基特松梢小卷蛾（Rhyacionia frustrana (Comstock)，鳞翅目：卷蛾科）的操作可行性。2000年，在楠塔基特松梢小卷蛾的第二代发生期，将含有两批被包裹微小赤眼蜂的单一淹没式释放物，以每公顷每批224,200 ± 27,600头雌蜂的潜在释放率，释放到两个4公顷的地块中。增加释放量未能使寄生率高于自然发生的水平；然而，受楠塔基特松梢小卷蛾侵害的嫩梢数量减少了10%，但未低于可接受水平。质量控制数据表明，微小赤眼蜂的羽化水平较低，且蚂蚁对发育中的微小赤眼蜂的捕食强度较大，导致实际释放率降至每公顷每批13,000 ± 900头雌蜂。研究了卵囊分布和小气候对捕食者发现卵囊（以一些麦蛾卵被移除表示）、寄生蜂捕食（卵被移除或破坏的百分比）以及随后寄生蜂羽化的影响。均匀分布的卵囊比成簇分布的卵囊遭受的捕食水平显著更高，且暴露于田间条件5天的卵囊比暴露3天的卵囊遭受的捕食更多，与分布方式无关。捕食者发现卵囊不受分布或暴露时间的影响。微生境对平均每日最高温度、每天35摄氏度及以上的连续小时数以及寄生蜂羽化百分比有显著影响。随着每天35摄氏度及以上连续小时数的增加，寄生蜂羽化显著下降。小气候对捕食者发现卵囊或捕食水平没有影响。在火炬松种植园中，通过释放微小赤眼蜂来抑制楠塔基特松梢小卷蛾的危害可能并不实用。
