Abstract：
The fall webworm (FWW), Hyphantria cunea Drury (Lepidoptera: Erebidae), is an invasive and polyphagous insect pest of many economically important crops such as hazelnuts, apple, and mulberry. Recently, there have been an increasing number of reports about the damaging activities of FWW from hazelnut growing areas of Turkey indicating that currently existing control methods fail to satisfy the expectations of growers. Entomopathogenic nematodes (EPNs) in the Steinernematidae and Heterorhabditidae (Nematoda: Rhabditida) families and the symbiotic bacteria they carry in their intestine have a great potential for the management of many agriculturally important pests. In this study, the symbiotic bacteria of local EPN species (Heterorhabditis bacteriophora AVB-15, Steinernema feltiae KCS-4S, and Steinernema bicornotum MGZ-4S) recovered from the central Anatolia region was characterized using recA gene region as Photorhabdus luminescens, Xenorhabdus bovienii and Xenorhabdus budapestensis. The contact (25, 50, 100, 200 IJs/Petri) and oral efficacies of the infective juveniles (IJs) (25, 50, 100, 200 IJs/leaf) of these EPN isolates determined on 3rd/4th instar larvae, and cell-free supernatants from the identified symbiotic bacteria were evaluated separately on the 3rd and 4th larval instars of FWW in Petri dish environment under laboratory conditions (25 ± 1 °C, 60% of RH). In the Petri dish bioassays of EPN species, the most pathogenic isolate at the 1st DAT and 4th DAT was S. feltiae which caused 50% mortality at the highest concentration (200 IJs/Petri) and the highest mortality rate (97.5%) were achieved at 4th DAT by H. bacteriophora AVB-15 isolate. Surprisingly, the mortality rates were generally higher at the lowest concentrations and 82.5% mortality were reached 4th DAT by S. bicornotum at the lowest concentration (25 IJs/leaf) in the leaf bioassays. Mortality rates were higher in both Petri dish and filter paper efficacies of cell-free supernatants at the 2nd DAT and the highest mortality (87.5%) was reached in the contact efficacy studies when applied X. bovienii KCS-4S strain. The results suggest that the tested EPN species and CFSs have good potential for biological control of the larvae of FWW and can contribute to the IPM programs of FWW. However, the efficacy of both IJs of EPNs and CFSs of their symbiotic bacteria on larvae of FWW requires further studies to verify their efficiency in the field.
摘要：
秋季网虫（FWW），美国白蛾（鳞翅目：Erebidae），是许多经济上重要的作物如榛子的入侵和多食性害虫，苹果,还有桑树.最近,关于土耳其榛子种植区FWW的破坏性活动的报道越来越多，这表明目前现有的控制方法无法满足种植者的期望。Steinernemedae和Heterorhabditidae（Nematoda：Rhabditida）家族中的昆虫病原线虫（EPN）及其在肠道中携带的共生细菌在管理许多农业上重要的害虫方面具有巨大的潜力。在这项研究中,当地EPN物种的共生细菌(HeterorabditisbacteriophoraAVB-15，SteinernemafeltiaeKCS-4S，和从安纳托利亚中部地区回收的SteinernemabicornotumMGZ-4S）使用recA基因区域作为光致纹状体进行表征，博维恩和博维恩。在第3/4龄幼虫上确定的这些EPN分离株的感染性幼体（IJ）的接触（25、50、100、200IJ/叶）和口腔功效（IJ），在实验室条件（25±1°C，RH的60%)。在EPN物种的培养皿生物测定中，在第1DAT和第4DAT中，致病性最强的分离株是费蒂链球菌，在最高浓度（200IJs/Petri）下引起50％的死亡率，在第4DAT时，H.bacteriophoraAVB-15分离株实现了最高的死亡率（97.5％）。令人惊讶的是,在最低浓度下，死亡率通常较高，在叶片生物测定中，在最低浓度（25IJ/叶）下，双叶S.bicornotum达到了82.5％的死亡率。在第二个DAT时，无细胞上清液的培养皿和滤纸功效的死亡率均较高，并且当应用X.bovieniiKCS-4S菌株时，在接触功效研究中达到最高死亡率（87.5％）。结果表明，测试的EPN物种和CFSs具有良好的生物防治FWW幼虫的潜力，并且可以为FWW的IPM计划做出贡献。然而,EPN的IJ和其共生细菌的CFSs对FWW幼虫的功效需要进一步研究以验证其在该领域的效率。
