Incidence ofSoybean dwarf virusand Identification of Potential Vectors in Illinois

Abstract

Soybean dwarf virus (SbDV), which causes an important disease of soybeans in Japan, is persistently transmitted by aphids and is endemic in forage legumes in the United States. To determine the incidence of SbDV in Illinois, we collected clovers and forage legumes in a total of 49 Illinois counties in 2001 and 2002 and tested them for the presence of SbDV by reversetranscription-polymerase chain reaction. SbDV was detected in 43% of red clover (Trifolium pratense), 10% of white clover (T. repens), and 3% of yellow sweet clover (Melilotus officinalis) plant samples. The dwarfing strain (SbDV-D) was the predominant strain detected in Illinois. In 2000, Aphis glycines, an aphid species that colonizes soybeans, was reported for the first time in North America. To determine whether A. glycines or aphid species found colonizing clover were vectors of SbDV, transmission studies were conducted. Aphids of the species Nearctaphis bakeri reproducibly vectored SbDV among red clovers, and from red clover to soybean. A. glycines did not transmit SbDV; neither did two other clover-infesting aphid species, Acyrthosiphon pisum and Therioaphis trifolii.

Determining the duration of Aphis glycines (Hemiptera: Aphididae) induced susceptibility effect in soybean

“…Persistently transmitted viruses generally are acquired through extended feeding bouts and benefit from vector settling. Plant virus infection is unlikely to be the cause of the observed obviation of resistance as the only persistently transmitted soybean virus in North America is Soybean dwarf virus (Hartman 1999), which is rarely vectored by A. glycines (Harrison et al 2005;Wang et al 2006;Damsteegt et al 2011). Additional evidence that a plant virus is unlikely responsible for the obviation of resistance is the reduction in the response populations at 120 and 216 h for the virulent inducer population treatment.…”

Acquisition and Transmissibility of U.S. Soybean dwarf virus Isolates by the Soybean Aphid, Aphis glycines

“…In addition, 13 endemic SbDV isolates from black medic (Medicago lupulina L.), Chenopodittm sp., red clover (Trifolium pratense L.), soybean, subterranean clover (7: subterraneum L.), and white clover (T. repens L.) were obtained from two U.S. midPlant Disease / August 2011 945 Atlantic (6,7) and one midwestem state (11). These isolates were used in transmission studies with A. glycines (Table 1).…”

“…The originally described Japanese soybean strains (SbDV-DS and SbDV-YS), hereinafter called SbDV-D and SbDV-Y, and a subterranean clover red-leaf virus (SCRLV, now synonymous with SbDV) described in Australia (20) were transmitted almost exclusively by Aulacorthum solani Kaltenbacb. An isolate serologically related to SCRLV found in California (19), and other related isolates found worldwide, were transmitted by Acyrthosiphon pisum (Harris) and other aphid species (7,11,16,22,23), and not by A. solani. More recently, dwarfing and yellowing strains of SbDV (SbDV-DP and SbDV-YP) have been described from Japan tbat were transmitted by Acyrthosiphon pisum (37).…”

“…More recently, dwarfing and yellowing strains of SbDV (SbDV-DP and SbDV-YP) have been described from Japan tbat were transmitted by Acyrthosiphon pisum (37). Except for one report (15), all earlier attempts to transmit strains of SbDV by tbe soybean aphid Aphis glycines Matsumora have been unsuccessful (11,32,41). The soybean apbid has been reported to transmit several plant vinises (4,11) including tbe Indonesian Soybean dwarf virus (17).…”

“…In both Japan and the United States, conflicting reports have been published on the ability of/4. glycines to transtiiit SbDV (11,15,34,36,38,41). In order to clearly determine possible connections between SbDV reports and the presence of the soybean aphid, extensive transmission experiments were conducted using several U.S. and Japanese isolates of SbDV.…”