Fecundity and longevity of greenbug affected by biotype and temperature

摘要

Greenbug, Schizaphis graminum (Rondani), is a major insect pest of small-grained cereals and sorghum, Sorghum bicolor (L.) Moench. Originally a pest of winter wheat, Triticum aestivum L., the greenbug first became a persistent pest of sorghum in theUnited States in 1968 (Harvey and Hackerott 1969). Since then, four greenbug biotypes, C, E, I, and K, that damage sorghum have developed. Greenbugs suck juices from and inject toxin into more than 70 grass hosts including sorghum (Michels 1986). Injurycan kill seedlings or severely limit the yield of more mature sorghum plants. Currently, biotypes E and I are dominant on sorghum. Resistant sorghums are the primary defense against greenbug damage. Little is known about how greenbug biotypes develop. Understanding greenbug biology and how biotypes develop is key to developing cultivars with sustainable resistance. The goal of this study was to assess the effect of temperature on the fecundity and longevity of greenbug biotypes E and I to better under-stand greenbug biology, and more accurately evaluate sorghums for resistance to greenbugs.