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By Robert Seay

University of Arkansas

                LITTLE ROCK, Arkansas (October 9, 2009) — Arkansas’ soybean growers have been beset by wet weather this entire season, say specialists with the University of Arkansas, Division of Agriculture.

Some producers were forced to replant four times, due to rains washing out spring plantings, and now, the soybean harvest has “completely stopped” across the state due to heavy rains, says Jeremy Ross, Extension agronomist.

The wet weather may have contributed as well to a wave of split soybean pods.

When the pods split, they “allowed all of the moisture from all of the rains to germinate the seed inside the pod,” says Eugene Terhune, Woodruff County extension agent, UofA Division of Agriculture.  As a result, the seedling dies and rots.

Several growers, consultants and Extension county agents have reported green pods splitting around the R6, or “full seed,” stage of growth, says Ross. “The consensus is the soybean plants went through some stress which caused a reduction in pod size,” he says.

The reduction in pod size coupled with normal growth of the seed creates split pods, says Dennis Egli, Ph.D., crop physiology professor at the University of Kentucky.

“When the seed reaches its maximum volume, the seed is wedged tightly into the locule and often the ends of the seeds are flat where they come together, suggesting that there is substantial force involved,” he says.

Reports of split pods began three or four weeks ago, says Ross.  Since then, reports have emerged indicating seed rot, moldy seed, and sprouting seed.  “The only thing that growers can do now is to harvest these fields as quickly as possible,” he says.

Some growers may have even less to harvest due to green bean syndrome (GBS), a problem that has plagued Arkansas fields for decades, says John Rupe, Extension professor of plant pathology, UofA Division of Agriculture.

“With GBS, plants in large areas of fields fail to mature, remaining green long after the rest of the field is ready to harvest,” he says.  Leaves and stems of affected pods remain green and there is a proliferation of pods at the nodes.

Last year GBS was observed in a number of fields in Prairie County with damage ranging from 10 to 100 percent of the plants, says Rupe.

A precise diagnosis of the problem has eluded growers so far.  “We don’t know what causes this condition,” says Terhune.

“Suspected agents include pathogens like viruses or phytoplasmas and insects like stinkbugs, but there could also be interactions with soil factors, cultivar, and environment,” says Rupe.

Growers who observe fields with GBS or other unusual symptoms should contact their local county Extension agents as soon as possible.

For more information about this year’s soybean harvest, visit Extension’s Web site, www.uaex.edu, or contact your county Extension agent.  The Cooperative Extension Service is part of the U of A Division of Agriculture.