Westgate P J, Schultz B B, Hazzard R V
Kleinfelder Inc., 500 Enterprise Dr., Suite 4B, Rocky Hill, CT 06067 (
School of Natural Science, Hampshire College, Amherst, MA 01002 (
J Econ Entomol. 2017 Apr 1;110(2):507-516. doi: 10.1093/jee/tow260.
In the northeastern United States, control of Lepidopteran pests of sweet corn, particularly corn earworm [Helicoverpa zea (Boddie)], is difficult using organic methods. The direct application of corn oil and Bacillus thuringiensis (Bt) to corn silk has been shown to reduce ear damage from corn earworm in past studies; these studies sought to optimize this method by evaluating additional carrier and biopesticide mixtures that comply with the United States Federal Insecticide, Fungicide, and Rodenticide Act and National Organic Standards. Carriers, which are liquids used to dissolve the biopesticide and deliver it into the tip of the ear, may have phytotoxic or insecticidal properties. Experiments conducted from 2001 to 2005 evaluated caterpillar damage and ear development effects from carriers (vegetable and paraffinic oils and carrageenan), biopesticides (Bt, spinsosad, and neem), and three emulsifiers in various combinations when applied directly to the tips of the ears 5-7 d after silk initiation. There were no effects of emulsifiers on ear quality, except for slight reduction in caterpillar damage in one of the two years. There were no differences among corn, soy, canola, and safflower oils in corn earworm control or tip development. The carrageenan carrier had the least effect upon ear development as measured by the length of nonpollinated kernels at the tip, compared to corn oil or paraffinic oil (JMS Stylet Oil), which caused the greatest tip damage as well as an oily discoloration. The carrier-pesticide combinations with the best ear quality overall were spinosad in carrageenan or corn oil, and Bt in carrageenan.
在美国东北部，采用有机方法防治甜玉米的鳞翅目害虫，尤其是玉米穗虫[棉铃虫（Helicoverpa zea (Boddie)）]很困难。过去的研究表明，将玉米油和苏云金芽孢杆菌（Bt）直接施用于玉米花丝可减少玉米穗虫对玉米穗的损害；这些研究试图通过评估符合美国联邦杀虫剂、杀菌剂和杀鼠剂法案以及国家有机标准的其他载体和生物农药混合物来优化这种方法。载体是用于溶解生物农药并将其输送到玉米穗尖端的液体，可能具有植物毒性或杀虫特性。2001年至2005年进行的实验评估了载体（植物油、石蜡油和角叉菜胶）、生物农药（Bt、多杀菌素和印楝）以及三种乳化剂以各种组合在玉米花丝抽出后5 - 7天直接施用于玉米穗尖端时对毛虫损害和玉米穗发育的影响。除了在两年中的一年毛虫损害略有减少外，乳化剂对玉米穗质量没有影响。玉米油、大豆油、菜籽油和红花油在防治玉米穗虫或玉米穗尖端发育方面没有差异。与玉米油或石蜡油（JMS Stylet Oil）相比，角叉菜胶载体对玉米穗发育的影响最小，玉米油或石蜡油会导致最大程度的尖端损害以及油性变色。总体而言，玉米穗质量最佳的载体 - 农药组合是角叉菜胶或玉米油中的多杀菌素，以及角叉菜胶中的Bt。
