Soybean puckering and dwarfing

This article was originally published on July 20, 2012 and expired on August 30, 2012. It is provided here for archival purposes and may contain dated information.

A recent sample received at the University of Illinois Plant Clinic presented confusing symptomology, according to University of Illinois Plant Diagnostic Clinic and Integrated Pest Management coordinator Suzanne Bissonnette.

New leaves were puckered; older leaves were just a bit off color. The sample plant was not stunted, although the client reported that there were stunted plants in that area of the field.

Causes of puckering include herbicide drift or carryover, heat, and leaf hoppers. None of these possibilities seemed to explain the symptoms.

"We had the sample tested for virus infection," said Bissonnette. The sample was positive for a virus that is rather new to this area, soybean dwarf virus (SbDV).

Soybean dwarf virus has a serious economic impact in Japan. Symptoms are dwarfing and reduced seed set of the soybean plant, which can be severe if the plant is infected in the seedling stage.

"Our sample was not severely dwarfed, unlike other plants in the field, most likely because it was infected later in season," Bissonnette said.

University of Illinois USDA-Agricultural Research Service virologist Les Domier, who does research on the virus, first reported SbDV disease in Illinois in the 2006 soybean crop. Prior to that, SbDV was known to be endemic in red and white clover but had been detected in soybean only in Wisconsin and Virginia.

In the forage legumes, the virus is transmitted by several colonizing aphid species. Recent research on SbDV was concerned with whether soybean aphid, a soybean colonizing aphid, would be a good vector of SbDV and, if that were the case, would the incidence of SbDV increase in Illinois fields?

The answer is – probably not. A multistate study looking at transmission of SbDV by various aphids found that soybean aphid is an inefficient vector of the virus. However, the authors concluded that, although transmission of SbDV by the soybean aphid is very inefficient, the large populations of this insect that develop on soybean may have the potential to produce serious SbDV-induced yield losses.

What can be done about the disease?

"We have no recommendations for control," Bissonnette said. "Dr. Domier notes that resistance to SbDV has not been found in soybean. However, some cultivars show only mild symptoms when infected by the virus."

Watch for SbDV when scouting in soybean fields, Bissonnette advises.

"Diseases can and do change in their distribution more frequently than we like," she noted. "It may surprise you to know that SbDV is actually more common in Illinois than our old friend soybean mosaic virus."

Source: Suzanne Bissonnette, Plant Diagnostic Clinic and IPM coordinator, sbissonn@illinois.edu

Pull date: August 30, 2012