Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA.
J Econ Entomol. 2009 Dec;102(6):2146-53. doi: 10.1603/029.102.0618.
Field experiments were conducted in 2004 and 2005 to determine the effect of different levels of hand-infested third instar European corn borer, Ostrinia nubilalis (Hiibner) (Lepidoptera: Crambidae), on whole-plant yield and plant growth stage in corn, Zea mays L., grown for silage. In 2004 and 2005, European corn borer infestation level had a significant negative impact on whole-plant yield (grams of dry matter per plant) with increasing infestation; however, whole-plant yield was not significantly affected by plant growth stage in either year. In 2004, the six larvae per plant treatment caused the greatest percentage of reduction (23.4%) in mean (+/-SEM) whole-plant yield (258.5 +/- 21.0 g dry matter per plant) compared with the Bacillus thuringiensis (Bt) CrylAb control (337.3 +/- 11.1 g dry matter per plant). In 2005, the five larvae per plant treatment caused the greatest percentage of reduction (8.3%) in mean whole-plant yield (282.3 +/- 10.8 g dry matter per plant) compared with the Bt CrylAb control (307.8 +/- 8.3 g dry matter per plant). The relationship between mean whole-plant yield and European corn borer larvae infestation level from the pooled data of both years was described well by using an exponential decay model (r2 = 0.84, P = 0.0038). The economic injury level for silage corn was estimated to be approximately 73% higher than for corn grown for grain based on similar control costs and crop values. In addition, plant growth stage and European corn borer infestation level had no effect on percentage of acid detergent fiber, neutral detergent fiber, and crude protein values in either year of the study.
2004 年和 2005 年进行了田间试验，以确定不同水平的三龄欧洲玉米螟幼虫（奥斯特里尼亚·努比利纳里斯（希布纳））对玉米青贮作物的整株产量和植物生长阶段的影响。在 2004 年和 2005 年，随着欧洲玉米螟虫口密度的增加，虫口密度对整株产量（每株植物的干物质克数）有显著的负面影响；然而，在这两年中，植物生长阶段对整株产量没有显著影响。2004 年，每株 6 头幼虫的处理导致平均（+/-SEM）整株产量（每株植物 258.5 +/- 21.0 克干物质）的最大百分比减少（23.4%），与苏云金芽孢杆菌（Bt）Cry1Ab 对照（每株植物 337.3 +/- 11.1 克干物质）相比。2005 年，每株 5 头幼虫的处理导致平均整株产量（每株植物 282.3 +/- 10.8 克干物质）的最大百分比减少（8.3%），与 BtCry1Ab 对照（每株植物 307.8 +/- 8.3 克干物质）相比。使用指数衰减模型（r2 = 0.84，P = 0.0038）很好地描述了两年汇总数据中平均整株产量与欧洲玉米螟幼虫虫口密度之间的关系。基于类似的控制成本和作物价值，青贮玉米的经济危害水平估计比用于谷物的玉米高约 73%。此外，在研究的两年中，植物生长阶段和欧洲玉米螟虫口密度对酸性洗涤剂纤维、中性洗涤剂纤维和粗蛋白值的百分比没有影响。
