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The soybean outlook continues to be bearish for 2010 based on overplantings among farmers looking to rotate away from lower corn prices earlier this year. However, the soybean fungus disease (which has been an intermittent topic of discussion) has reared its head again during the late harvest season.
Soybean Rust Spreading Fast, But May Be Too Late To Harm Crop
Asian soybean rust is spreading rapidly, threatening late-planted fields as far north as the lower Ohio River Valley within the past few days.
The plant disease has been found in a total of 59 counties in Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, Missouri and Tennessee during the past week alone.
“We’ve had ideal weather for soybean rust,” said Allen Wrather, University of Missouri extension plant pathologist. “A slow-moving low-pressure system brought intermittent rain and mild temperatures.” Weather conditions affect spread of the fungus. Rust spores must have 10-14 hours of wet-leaf contact before they germinate and infect the plant. Warm, dry
sunshiny weather often kills the seedspores outright.
Spores of the fast-moving fungus are spread by the wind and can cause rapid yield losses, unless almost immediately countered by chemical fungicide. Even so, some farmers may choose not to spray, due to the late onset of the disease, this season. Most soybean fields in southeast Missouri are now at filled-pod stage of development, Wrather said. “Their yield will not likely be reduced by rust.” However, late-planted soybean plants that emerged in July are just now beginning to fill the seed-pod. "Yields of those plants may be reduced by rust if not treated with a fungicide,”
he said. “The decision to spray is an economic decision. Fields with low
yield potential, say 20 bushels, might not pay to spray.”
Fungicide applications usually cost $12-$15 per acre. “As the soybean crop matures, more soybean rust reports are expected north of the current distribution” area, warned the USDA on Tuesday.
Soybean rust hasn’t yet been detected in Indiana, although it has been reported across the Ohio River in northern Kentucky. “It is possible that rust is present in southern Indiana at very low levels, and we have increased scouting in those areas in order to document any finds,” said
Purdue University plant pathologist Kiersten Wise. “Even if soybean rust is
detected over the next few weeks, the level of disease would be very low, and the majority of the soybean crop is past the point of economic damage occurring.”
The USDA’s latest rust infection forecast says more rust-favoring wet weather is anticipated this week as an area of low pressure moves northeastward across the Great Plains.
Source: CME News for Tomorrow
