Department of Entomology, 1-31 Agriculture Bldg., University of Missouri, Columbia, MO 65211, USA.
J Insect Sci. 2010;10:144. doi: 10.1673/031.010.14104.
Although soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), has caused economic damage in several Midwestern states, growers in Missouri have experienced relatively minor damage. To evaluate whether existing predatory insect populations are capable of suppressing or preventing soybean aphid population growth or establishment in Missouri, a predator exclusion study was conducted to gauge the efficacy of predator populations. Three levels of predator exclusion were used; one that excluded all insects (small mesh), one that excluded insects larger than thrips (medium mesh), and one that excluded insects larger than Orius insidiosus (Say) (Hemiptera: Anthocoridae), a principal predator (large mesh). Along with manipulating predator exposure, timing of aphid arrival (infestation) was manipulated. Three infestation times were studied; vegetative (V5), beginning bloom (R1), and beginning pod set (R3). Timing of aphid and predator arrival in a soybean field may affect the soybean aphid's ability to establish and begin reproducing. Cages infested at V5 and with complete predator exclusion reached economic threshold within two weeks, while cages with predators reached economic threshold in four and a half weeks. Cages infested at R1 with complete predator exclusion reached economic threshold within five weeks; cages with predators reached economic threshold within six weeks. Cages infested at R3 never reached threshold (with or without predators). The predator population in Missouri seems robust, capable of depressing the growth of soybean aphid populations once established, and even preventing establishment when the aphid arrived late in the field.
虽然大豆蚜虫，Aphis glycines Matsumura（半翅目：蚜科），已经在几个中西部州造成了经济损失，但密苏里州的种植者经历的破坏相对较小。为了评估现有的捕食性昆虫种群是否能够抑制或阻止大豆蚜虫在密苏里州的种群增长或建立，进行了一项捕食者排除研究，以评估捕食者种群的功效。使用了三种水平的捕食者排除；一种排除所有昆虫（小网眼），一种排除大于蓟马的昆虫（中网眼），一种排除大于 O. insidiosus（Say）（半翅目：Anthocoridae）的昆虫（大黄蜂），这是主要的捕食者（大网眼）。除了操纵捕食者的暴露外，还操纵了蚜虫到达（侵染）的时间。研究了三种侵染时间；营养生长（V5）、开花初期（R1）和开始结荚（R3）。蚜虫和捕食者在大豆田中的到达时间可能会影响大豆蚜虫建立和开始繁殖的能力。在 V5 侵染且完全排除捕食者的笼子在两周内达到经济阈值，而有捕食者的笼子则在四周半后达到经济阈值。在 R1 侵染且完全排除捕食者的笼子在五周内达到经济阈值；有捕食者的笼子在六周内达到经济阈值。在 R3 侵染的笼子（无论是否有捕食者）从未达到阈值。密苏里州的捕食者种群似乎很强大，一旦建立起来，能够抑制大豆蚜虫种群的生长，甚至可以防止蚜虫在田间后期到达时建立。
