Reay-Jones F P F, Bessin R T, Brewer M J, Buntin D G, Catchot A L, Cook D R, Flanders K L, Kerns D L, Porter R P, Reisig D D, Stewart S D, Rice M E
Department of Agricultural and Environmental Sciences, Pee Dee Research and Education Center, Clemson University, 2200 Pocket Rd., Florence, SC 29506-9727 (
Department of Entomology, University of Kentucky, S-225 Ag North, Lexington, KY 40546 (
J Econ Entomol. 2016 Aug;109(4):1859-71. doi: 10.1093/jee/tow109. Epub 2016 Jun 21.
Blended refuge for transgenic plants expressing Bacillus thuringiensis (Bt) toxins has been approved in the northern United States as a resistance management strategy alternative to a structured refuge. A three-year study (2012-2014) was conducted with 54 trials across nine states in the southern United States to evaluate plant injury from lepidopteran pests of corn and yield in a corn hybrid expressing Cry1F × Cry1Ab × Vip3Aa20 (Pioneer Brand Optimum Leptra) planted as a pure stand and in refuge blends of 5, 10, and 20% in both early and late plantings. Injury by corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), and fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), was generally proportional to the percentage of non-Bt corn within each refuge blend. Across locations, ear injury in plots with 100% Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) corn ranged from no injury to a maximum of 0.42 cm(2) per ear in Mississippi in 2013. Leaf injury ratings in 100% non-Bt plots in early and late planted trials in 2014 were 86- and 70-fold greater than in 100% Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) plots. Plants in plots with blended refuges had significantly greater leaf injury in 2012 (5, 10, and 20% refuge blends), in the early-planted corn in 2013 (10 and 20% only), and in both early- and late-planted corn in 2014 (20% only) as compared with leaf injury in a pure stand of Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) seen during these years. Corn ears in plots with blended refuges also had significantly greater area of kernels injured in 2012 (5, 10, and 20%), in early- and late-planted corn in 2013 (5, 10, and 20%), and in early (10 and 20% only)- and late-planted corn (5, 10, and 20%) in 2014 as compared with ear injury in a pure stand of Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra) seen during these years. Infestations of southwestern corn borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae), were also significantly reduced by Cry1F × Cry1Ab × Vip3Aa20 (Optimum Leptra). Despite these differences in injury, yield averaged across locations varied among refuge blends only in the late-planted trials in 2013, with greater yields in the 0% refuge blend than in the 20% blend; however, when examining yield separately by location, only two of nine locations had higher yields in the 100% Bt plots than in any of the blended refuge plots. As a complement to studying the contribution of blended refuge to delaying resistance, quantifying injury and yield in a range of refuge blends is a necessary step to provide management information on the range of lepidopteran pests that occur in the southern United States.
在美国北部，表达苏云金芽孢杆菌（Bt）毒素的转基因植物混合避难所已被批准作为一种抗性管理策略，替代结构化避难所。在美国南部九个州进行了一项为期三年（2012 - 2014年）的研究，共进行了54次试验，以评估种植为纯林以及在早播和晚播中分别占5%、10%和20%的避难所混合种植的表达Cry1F×Cry1Ab×Vip3Aa20（先锋品牌Optimum Leptra）的玉米杂交种中，玉米鳞翅目害虫造成的植株伤害和产量。棉铃虫Helicoverpa zea Boddie（鳞翅目：夜蛾科）和草地贪夜蛾Spodoptera frugiperda（J. E. Smith）（鳞翅目：夜蛾科）造成的伤害通常与每个避难所混合种植中非Bt玉米的百分比成正比。在各个地点，种植100% Cry1F×Cry1Ab×Vip3Aa20（Optimum Leptra）玉米的地块中，穗部伤害从无伤害到2013年密西西比州每穗最高0.42平方厘米不等。2014年早播和晚播试验中100%非Bt地块的叶片伤害评级分别比100% Cry1F×Cry1Ab×Vip3Aa20（Optimum Leptra）地块高86倍和70倍。与这些年份中100% Cry1F×Cry1Ab×Vip3Aa20（Optimum Leptra）纯林的叶片伤害相比，2012年（5%、10%和20%避难所混合种植）以及2013年早播玉米（仅10%和20%）和2014年早播和晚播玉米（仅20%）中，混合避难所地块中的植株叶片伤害显著更大。2012年（5%、10%和20%）、2013年早播和晚播玉米（5%、10%和20%）以及2014年早播（仅10%和20%）和晚播玉米（5%、10%和20%）中，混合避难所地块中的玉米穗上受损伤籽粒的面积也比这些年份中100% Cry1F×Cry1Ab×Vip3Aa20（Optimum Leptra）纯林的穗部伤害显著更大。西南玉米螟Diatraea grandiosella Dyar（鳞翅目：草螟科）的侵染也因Cry1F×Cry1Ab×Vip3Aa20（Optimum Leptra）而显著减少。尽管存在这些伤害差异，但各地点的平均产量仅在2013年晚播试验中因避难所混合比例不同而有所变化，0%避难所混合比例的产量高于20%混合比例；然而，按地点分别考察产量时，九个地点中只有两个地点100% Bt地块产量高于任何混合避难所地块。作为研究混合避难所在延缓抗性方面贡献的补充，量化一系列避难所混合比例下的伤害和产量是提供有关美国南部发生的鳞翅目害虫范围管理信息的必要步骤。
