Tuesday, December 11, 2007 - 4:11 PM

Soybean aphid (Aphis glycines Matsumura) is a vector of PLRV

Jeff Davis, davis271@tc.umn.edu and Edward B. Radcliffe, RADCL001@umn.edu. University of Minnesota, Department of Entomology, 1980 Folwell Ave, St. Paul, MN

Experiments were undertaken to (i) determine if soybean aphid, Aphis glycines Matsumura, could acquire, retain, and transmit Potato leafroll virus (PLRV) and (ii) compare its feeding behavior with that of green peach aphid, Myzus persicae (Sulzer), on potato. Soybean aphid acquired PLRV 78% of the time, 73% and 70% retaining infectivity 72 h and 144 h, respectively. Soybean aphid transmitted PLRV at 9% efficiency. Electrical penetration graphs (EPG) showed no significant differences between the aphid species in pre-probe, xylem phase, sieve element salivation and phloem sap ingestion durations on potato. Prior to invasion of soybean aphid, soybean crop borders were commonly used by Minnesota and North Dakota seed potato growers to protect against Potato virus Y spread. Experiments were done to determine if soybean aphid infested soybean borders would increase PLRV spread. Cumulative soybean aphid days (CSBAD) on insecticide-treated borders were 636 in 2002, 3 in 2004, and 160 in 2005. Untreated borders had CSBAD of 15,139 in 2002, 708 in 2004, and 28,170 in 2005. PLRV spread in potatoes was not different with insecticide-treated and untreated borders in 2002 and 2004 (χ2=0.034, 1.085; df=1, 1; P=0.8545, 0.2977; respectively). In 2005, with extreme soybean aphid pressure, untreated borders had significantly greater PLRV spread (χ2=8.385; df=1; P=0.0038). This is the first indication that soybean aphid can transmit PLRV.

Species 1: Hemiptera Aphididae Aphis glycines (soybean aphid)