Sparks A N, Gadal L, Ni X
University of Georgia, Tifton Campus, Tifton, 2360 Rainwater Rd., Tifton, GA 31793.
Institut National de la Recherche Agronomique, Montpellier, France.
J Econ Entomol. 2015 Aug;108(4):1869-74. doi: 10.1093/jee/tov113. Epub 2015 May 7.
The primary Lepidoptera pests of sweet corn (Zea mays L. convar. saccharata) in Georgia are the corn earworm, Helicoverpa zea (Boddie), and the fall armyworm, Spodoptera frugiperda (J. E. Smith). Management of these pests typically requires multiple insecticide applications from first silking until harvest, with commercial growers frequently spraying daily. This level of insecticide use presents problems for small growers, particularly for "pick-your-own" operations. Injection of oil into the corn ear silk channel 5-8 days after silking initiation has been used to suppress damage by these insects. Initial work with this technique in Georgia provided poor results. Subsequently, a series of experiments was conducted to evaluate the efficacy of silk channel injections as an application methodology for insecticides. A single application of synthetic insecticide, at greatly reduced per acre rates compared with common foliar applications, provided excellent control of Lepidoptera insects attacking the ear tip and suppressed damage by sap beetles (Nitidulidae). While this methodology is labor-intensive, it requires a single application of insecticide at reduced rates applied ∼2 wk prior to harvest, compared with potential daily applications at full rates up to the day of harvest with foliar insecticide applications. This methodology is not likely to eliminate the need for foliar applications because of other insect pests which do not enter through the silk channel or are not affected by the specific selective insecticide used in the silk channel injection, but would greatly reduce the number of applications required. This methodology may prove particularly useful for small acreage growers.
佐治亚州甜玉米（Zea mays L. convar. saccharata）的主要鳞翅目害虫是玉米穗虫，即棉铃虫（Helicoverpa zea (Boddie)）和秋粘虫，即草地贪夜蛾（Spodoptera frugiperda (J. E. Smith)）。对这些害虫的防治通常需要从抽丝初期到收获期多次施用杀虫剂，商业种植者经常每天喷洒。这种杀虫剂使用水平给小农户带来了问题，尤其是对于“自采”作业而言。在开始抽丝后5 - 8天向玉米穗丝通道注入油已被用于抑制这些昆虫造成的损害。在佐治亚州对该技术进行的初步试验效果不佳。随后，进行了一系列实验来评估向丝通道注射杀虫剂作为一种施药方法的效果。与常见的叶面施药相比，以大幅降低的每英亩用量单次施用合成杀虫剂，能很好地防治攻击玉米穗尖的鳞翅目昆虫，并抑制露尾甲（Nitidulidae）造成的损害。虽然这种方法劳动强度大，但与在收获当天之前可能每天以全量进行叶面杀虫剂施药相比，它只需在收获前约2周以降低的用量单次施用杀虫剂。由于其他害虫不会通过丝通道进入或不受丝通道注射中使用的特定选择性杀虫剂影响，这种方法不太可能消除叶面施药的需求，但会大大减少所需的施药次数。这种方法可能对小面积种植者特别有用。
