Heve William K, El-Borai Fahiem E, Johnson Evan G, Carrillo Daniel, Crow William T, Duncan Larry W
Citrus Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 700 Experiment Station Road, Lake Alfred, Florida, 33850.
Tropical Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 18905 SW 280th Street, Homestead, Florida, 33031.
J Nematol. 2018;50(3):261-272. doi: 10.21307/jofnem-2018-039.
Caribbean fruit fly, also known as Caribfly or Anastrepha suspensa , is a major tephritid pest of guavas. A virulent entomopathogenic nematode (EPN) species was investigated to suppress the fruit-to-soil stages of Caribflies, which are also attacked by the koinobiont parasitoid Diachasmimorpha longicaudata in south Florida. The main objective was to develop a feasible and cost-effective EPN-application method for integrated pest management (IPM) of Caribfly to improve guava production. Naturally infested guavas were treated with increasing Heterorhabditis bacteriophora infective juvenile (IJ) concentration or rate (0, 25, 50, …, 1,600 IJs cm -2 ) in field trials to measure the optimum IJ rate and then examine sensitivity of producing guavas to inclusion of Heterorhabditis bacteriophora in Caribfly IPM plans. Relative survival of Caribfly in treatments significantly decreased with increasing IJ rate from 0 to 100 IJs cm -2 . Similarly, probability of observing large numbers of parasitoid wasps ( Diachasmimorpha longicaudata ) in EPN treatments significantly declined with increasing IJ rate (0-100 IJs cm -2 ), even though the non-target effects of Heterorhabditis bacteriophora on relative survival of Diachasmimorpha longicaudata could not be determined because of few emerging parasitoid wasps. Optimum suppression (⩾ 60%) of Caribfly was consistently achieved at 100 IJs cm -2 or 17,500 IJs fruit -1 . Profitability analysis showed that Heterorhabditis bacteriophora can be included in Caribfly IPM tactics to produce guavas. Costs of EPNs in Caribfly IPM are minimized if Heterorhabditis bacteriophora is strategically applied by spot treatment of fruit. Repayment of costs of EPN-augmentation by spot treatments appears achievable by recovering 5.71% of the annual yield losses (⩾1,963 kg ha -1 ≈ US$ 8,650 ha -1 ), which are largely due to Caribfly infestation. Hectare-wide EPN-augmentation (or broadcasting) method requires more fruit recovery than the total annual yield losses to repay its high costs. Profitability of guava production in south Florida will not be very sensitive to marginal costs of the spot treatment method, when compared to the field-wide broadcasting of Heterorhabditis bacteriophora .
加勒比果蝇，也被称为加勒比实蝇或悬铃木果实蝇，是番石榴的一种主要实蝇害虫。研究了一种具有致病性的昆虫病原线虫（EPN）物种，以抑制加勒比果蝇从果实到土壤阶段的生长，在佛罗里达州南部，这些阶段的果蝇也会受到共寄生性寄生蜂长尾潜蝇茧蜂的攻击。主要目标是开发一种可行且具有成本效益的EPN应用方法，用于加勒比果蝇的综合虫害管理（IPM），以提高番石榴产量。在田间试验中，用递增浓度或比率（0、25、50、…、1600条感染性幼虫/cm²）的嗜菌异小杆线虫感染性幼虫（IJ）处理自然感染的番石榴，以测量最佳IJ比率，然后检验在加勒比果蝇IPM计划中添加嗜菌异小杆线虫后，番石榴生产的敏感性。随着IJ比率从0增加到100条/cm²，处理中加勒比果蝇的相对存活率显著下降。同样，随着IJ比率（0 - 100条/cm²）增加，在EPN处理中观察到大量寄生蜂（长尾潜蝇茧蜂）的概率也显著下降，尽管由于羽化的寄生蜂数量较少，无法确定嗜菌异小杆线虫对长尾潜蝇茧蜂相对存活率的非靶标影响。在100条/cm²或17500条/果实的剂量下，始终能实现对加勒比果蝇的最佳抑制（⩾60%）。盈利能力分析表明，嗜菌异小杆线虫可纳入加勒比果蝇IPM策略以生产番石榴。如果通过对果实进行点施策略性地施用嗜菌异小杆线虫，在加勒比果蝇IPM中EPN的成本可降至最低。通过挽回5.71%的年产量损失（⩾1963 kg/公顷≈8650美元/公顷），点施处理似乎可以实现EPN增效成本的偿还，这些损失主要是由加勒比果蝇的侵害造成的。与公顷范围内的EPN增效（或撒施）方法相比，点施方法需要挽回更多的果实量才能偿还其高昂成本，公顷范围内的EPN增效（或撒施）方法需要挽回的果实量超过年产量损失总量才能偿还其高昂成本。与在整个田间撒施嗜菌异小杆线虫相比，佛罗里达州南部番石榴生产的盈利能力对该点施处理方法的边际成本不太敏感。
