BISHOPVILLE – Crop disease soybean rust has been found for the first time in the state of Maryland in a sentinel field in northern Worcester County, but experts say the disease should not affect the 2008 soybean crop.
“It happened at the very end of the growing season, and in fact frost had already damaged the uppermost foliage of this extremely late soybean sentinel plot,” said Dr. Arv Grybauskas, a plant pathologist with the University of Maryland extension service.
The sentinel field soybean plants have no green leaves at this point in the year and fields in production are at the harvest stage. Soybean rust is not transmitted by seed and cannot over-winter in local temperatures.
The soybean rust fungus originated in Asia and first appeared in the continental United States in 2004.
The Maryland occurrence was discovered by the Delaware Department of Agriculture from plant samples gathered from the north Worcester County sentinel field on Oct. 23. The samples were grown by the University of Delaware for several days and determined to be the more aggressive form of soybean rust, phakopsora pachyrhizi.
Soybean rust can reduce yields significantly, but agriculture scientists feel that they are on top of the situation.
“Our ability to detect soybean rust gives us the information to provide growers with an early warning in time to take protective measures in case it should appear earlier in the season when the crop could be at risk,” said Robert Mulrooney of the Delaware Soybean Rust Team. “Our detection program has been a very effective tool for monitoring the presence of soybean rust in the United States and preventing this disease from causing needless losses.”
Maryland has a strong soybean industry, with 103 million bushels harvested from 380,000 acres in 2007, valued at $107 million.
“The key message to take from this find is that soybean rust can blow into our region and under the right combination of temperature, moisture and plant susceptibility could cause infection in our soybean crop,” said Grybauskas. “It will take a combination of unusual events to provide those favorable conditions earlier in a growing season to be a significant threat. Nevertheless, we must keep vigilant to protect this significant component of our agricultural economy in the future.”