Berberet R C, Giles K L, Zarrabi A A, Payton M E
Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74076, USA.
Environ Entomol. 2009 Dec;38(6):1765-71. doi: 10.1603/022.038.0630.
The goal of this research was to describe developmental rates, reproductive rates, and infestation patterns of Aphis craccivora Koch on alfalfa (Medicago sativa L.). All studies were conducted on the susceptible cultivar OK08 using aphids reared from collections made in Oklahoma. To determine thermal requirements for growth of A. craccivora, development from birth to adult was recorded at 7.2, 12.8, 18.3, 23.9, and 29.4 degrees C. The same constant temperature treatments (except for 7.2 degrees C being raised to 8.3 degrees C) were used to assess the influence of temperature on reproductive rates. Within-plant distribution patterns were determined by infesting three stems on each of 24 plants and recording numbers of A. craccivora on leaf blades, petioles, and internodal stems sections at 2-d intervals through 10 d after infestation. Aphid counts were analyzed to determine significant differences among node parts (leaf blades, petioles, and stem sections). The developmental threshold temperature for A. craccivora was calculated to be 7.1 degrees C, and the thermal constant for development from the first instar to reproducing adult was 100 DD ( degrees C). The optimal temperature range for reproduction on alfalfa was 18-24 degrees C, with a mean of 82 nymphs produced per female. From the initial infestation of three apterae per stem, numbers increased to a mean of 510 per stem after 10 d. Plant profiles showed that the greatest numbers of aphids were located in middle and lower portions of the plant canopy. On all sampling dates, the proportion of aphids on internodal stem sections was significantly greater (P < 0.05) than on petioles and leaf blades.
本研究的目的是描述苜蓿蚜（Aphis craccivora Koch）在紫花苜蓿（Medicago sativa L.）上的发育速率、繁殖速率和侵染模式。所有研究均在易感品种OK08上进行，使用从俄克拉荷马州采集的蚜虫饲养后代。为了确定苜蓿蚜生长的温度需求，记录了在7.2、12.8、18.3、23.9和29.4摄氏度下从出生到成虫的发育情况。采用相同的恒温处理（除7.2摄氏度提高到8.3摄氏度外）来评估温度对繁殖速率的影响。通过在24株植物上每株侵染3个茎，并在侵染后10天内每隔2天记录苜蓿蚜在叶片、叶柄和节间茎段上的数量，来确定植株内的分布模式。对蚜虫数量进行分析，以确定不同节点部位（叶片、叶柄和茎段）之间的显著差异。计算得出苜蓿蚜的发育阈值温度为7.1摄氏度，从一龄若虫发育到繁殖成虫的热常数为100日度（摄氏度）。苜蓿蚜在紫花苜蓿上繁殖的最适温度范围为18 - 24摄氏度，平均每头雌蚜产若蚜82头。从每茎最初侵染3头无翅蚜开始，10天后数量增加到平均每茎510头。植株分布情况表明，蚜虫数量最多的部位位于植株冠层的中下部。在所有采样日期，节间茎段上的蚜虫比例显著高于（P < 0.05）叶柄和叶片上的蚜虫比例。
