Monday, December 11, 2006 - 9:23 AM

Host plant resistance studies with the sugarcane aphid (Homoptera: Aphididae) on sugarcane in Louisiana

W. Akbar, and T. E. Reagan, Louisiana State University Agricultural Center, 402 Life Sciences Bldg, Baton Rouge, LA

The sugarcane aphid, Melanaphis sacchari (Zehntner), although a minor pest of sugarcane in Louisiana is spreading throughout the industry and is the main vector of sugarcane yellow leaf virus. Host plant resistance is a management option successfully employed against various aphids in different cropping systems. Our studies were aimed at exploring possible sources of resistance to the sugarcane aphid in commercial or near-commercial germplasm of sugarcane in Louisiana. Five sugarcane cultivars (L 97-128, LCP 85-384, HoCP 96-540, HoCP 91-555, and Ho 95-988) were screened in greenhouse pot studies for antixenosis, antibiosis, and tolerance. Antixenosis tests did not show difference in aphid preference, but antibiosis tests indicated pronounced variation among varieties. The days in reproduction and number of nymphs produced were highest in L 97-128, while HoCP 91-555 depicted the strongest antibiosis with the least number of days in reproduction and fewest numbers of nymphs produced. Based on rm (intrinsic rate of aphid increase) values, it is estimated that L 97-128 can produce almost four times more numbers of sugarcane aphids as compared to the resistant variety i.e. HoCP 91-555. Other varieties showed intermediate levels of antibiotic resistance. Tolerance tests revealed similar results with HoCP 91-555 showing maximum tolerance and L 97-128 showing least tolerance in terms of chlorophyll contents recovery based on SPAD index readings. From these studies, an efficient and rapid system of aphid resistance evaluation is being established for the Louisiana varietal development program.

Species 1: Hemiptera Aphididae Melanaphis sacchari (sugarcane Aphid)

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