Infochemical-tritrophic Interactions of Soybean Aphids-host Plants-natural Enemies and Their Practical Applications in Pest Management

The soybean aphid, Aphis glycines Matsumura, is a newly invasive insect species that seriously threatens U.S. soybean production. This aphid pest has kept haunting many soybean growers by developing large colonies on soybeans in North America since 2000. Since its first appearance inWisconsin, it has spread to over half of US states and southern provinces in Canada. The heavy infestation of this pest whittles soybean growers’ profits and causes hundreds of million dollar losses. The present chapter will mainly describe efforts in studying aphid chemical ecology and sensory physiology for understanding how male aphids find their mates and host plants. It will also cover research efforts to understand host plant associated volatiles being used as cues for overwintering host plant location. In addition, findings on how soybean plant defensive system works against aphid infestation, as well as how those induced plant volatiles are used by aphid’s natural enemies for prey location will be presented. Finally, the use the basic understandings for developing useful tools for soybean aphid practical control will be discussed

Development, growth, feeding and reproduction of Ceratomegilla undecimnotata, Hippodamia variegata and Coccinella septempunctata fed on the tobacco aphid, Myzus persicae nicotianae

The demographic parameters and the larval aphid consumption of the predatory coccinellids Hippodamia variegata (Goeze) and Ceratomegilla undecimnotata (Schneider) were examined at five constant temperatures (17, 20, 23, 26, and 29 A degrees C). The same parameters were determined for Coccinella septempunctata L. at 23 A degrees C. A red Myzus persicae nicotiannae Blackman clone reared on tobacco leaves was used as prey. Preimaginal development of H. variegata and C. undecimnotata ranged from 12.4 to 40.6 days and 14.4 to 48.5 days at 17 A degrees C to 29 A degrees C, respectively. The corresponding thermal summation constants were 211 and 256 DD (day-degrees). Total and mean daily larval consumption at 26 A degrees C were 84.2 and 8.7 aphids, for H. variegata and 129.1 and 9.4 aphids, for C. undecimnotata, respectively. At 23 A degrees C, the mean fecundity of H. variegata, C. undecimnotata and C. septempunctata was 882, 656 and 586 eggs, respectively. The duration of the oviposition periods was 47.6, 50.4 and 73.4 days, respectively. The demographic parameters calculated for H. variegata, C. undecimnotata and C. septempunctata, were as follows: intrinsic rate of increase (r (m)) 0.129, 0.084, and 0.061 female/female/day; mean generation time (T) 42.4, 59.1, and 69.3 days; net reproductive rate (R-o) 241.9, 142.7, 67.3 female/female; and population duplication time (DT) 5.4, 8.3, and 11. 4 days. Total aphid consumption by a pair of adult male and female was 2381 aphids in H. variegata and 3242 aphids in C. undecimnotata. The possible role of the three predator species as biocontrol agents is discussed