Leaf Pubescence Effects in Wheat on Yellow Sugarcane Aphids and Greenbugs (Homoptera: Aphididae)

Abstract

Observations during previous wheat germ plasm evaluation tests indicated that wheat lines with high levels of leaf pubescence are resistant to the yellow sugarcane aphid, Sipha flava (Forbes). Earlier work also suggested the same relationship for the green bug, Schizo phis germanium (Ronni), but the evidence was not as strong. This research studied the effects of leaf pubescence on the two aphid species in greater detail. Trix home length and density measurements were made on second and third leaves from seedlings of six pubescent wheat entries and two nearly glabrous wheat cultivars. Yellow sugarcane aphid and greenbug antibiosis and antixenosis tests were conducted using standard methods for the antibiosis test and new techniques for the antixenosis test. The results showed that leaf surface pubescence is of questionable value in a greenbug; plant resistance program, but it is an effective resistance mechanism against the yellow sugarcane aphid.