August 3, 2006

 

Asian soybean rust detected in southern US

 

 

Asian soybean rust has been found in Mississippi, representing the sixth US state to discover an infection of the devastating plant disease thus far in 2006.

 

"Soybean rust has been found in two locations, one on soybeans and one on kudzu, both in Jefferson County (of south-western Mississippi, near Natchez)," reported Mississippi State University agronomist Alan Blaine via the US Department of Agriculture's public rust website late Tuesday (Aug 2).

 

Although rust was heavy on the infected kudzu--a common viney ditch-weed-- Blaine said "rust was difficult to find in soybeans," although he added that intensive scouting for the airborne fungus continues in commercial fields and sentinel plots.

 

Sentinel plots are tiny research fields of soybeans, especially designed to track movement of the disease, which can cause heavy yield losses via rapid and premature plant defoliation.

 

With virtually all Mississippi soybeans still immature, Blaine suggests that farmers in south-western sections of the state who have soybean fields at the pod-fill stage of development or younger, consider spraying their crop with chemical fungicide--the only known method of combating the pathogen.

 

National commentary provided by USDA noted that rust has now been found on soybeans in eight different counties of five states (Alabama, Florida, Georgia, Louisiana and Mississippi).

 

Overall the fungus has turned up in a total of 28 counties across Alabama, Florida, Georgia, Louisiana, Texas, and Mississippi, primarily on kudzu.

 

A rust forecast published by USDA early Tuesday predicted that hot and humid weather conditions, coupled with thunderstorms, overcast skies and onshore air-flow would increase the risk of new infections from Mississippi to Florida and southern Georgia in coming days.

 

Even so, with drought setting the development of rust about a month behind the 2005 schedule and prompting soybeans to mature more quickly than usual, experts do not feel that rust will pose a threat to more intensive areas of soybean production lying much farther north this season,

 

"Soybeans in our major growing areas in north Mississippi and the Delta have nothing to be concerned about at this time," assured Blaine. "It's been hot and extremely dry in those areas, unfavourable for rust development."