The information and recommendations in this newsletter are applicable to North Carolina and may not apply in other areas.
The information and recommendations in this newsletter are applicable to North Carolina and may not apply in other areas.
From: Steve Koenning and Jim Dunphy, Plant Pathology and Crop Science Extension Specialists
Soybean rust was confirmed on samples taken in Washington County, North Carolina. Rust was detected in the sentinel plots located in Washington, Scotland, Lenoir, and Edgecombe counties, and in surveys in Craven, Jones, and Beaufort Counties. Rust incidence in all locations was low. Other surveyed counties that were negative included Martin, Pitt, Onslow, Duplin, Moore, and Lee.
This brings to 11, the number of counties positive for soybean rust: Washington, Columbus, Robeson, Bladen, Brunswick, Scotland, Craven, Jones, Beaufort, Lenoir, and Edgecombe.
In many instances it is too late to apply fungicides to soybean, and the chances of measurable yield loss from soybean rust are minimal!
Little new infection has occurred recently in most of the state because of low temperatures when leaf wetness is high (early in the morning in most cases). Although rust probably got well distributed with recent wind and rain, weather forecasts are for lows in the low to mid 50’s for the next five days. Spores on leaves require 6 hours of leaf wetness at temperatures from 60 to 80 degrees Fahrenheit for infection to occur. Some infection will undoubtedly still occur in limited areas of some fields where shade or other factors influence microclimate in the canopy.
Still, it will most likely be 3 to 4 weeks before premature defoliation that will influence soybean yield will occur, and this will probably be in isolated areas of certain fields. Most soybeans will defoliate naturally over this period through the maturation process. Thus, the likelihood of a positive economic return from fungicide application is greatly reduced, even for late planted soybean.
Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
Last modified on October 2, 2006 by Stephen J. Toth, Jr.