Soybeans in Good Shape to Withstand Hot Weather

Depending on where you are, it’s been ideal weather for soybeans this year says Dr. Jim Dunphy, NC State Extension Soybean Specialist:

“It has in places, and still is in places, other places are too wet, others are too dry, we have them all in the state, and that’s typical.  Our weather tends to be spotty, and couple that up with some of our relatively shallow soils we’re in a situation where to keep our soybeans growing we could use a good rain every 10 days or so, and sometimes we get it, sometimes we don’t.  End result is a mixture, we’ve got too wet and too dry all over the state.”

It’s turned of hot and dry again in many areas of the state, and Dunphy says soybeans should do what they do best; shut down until conditions improve.  But, the heat has been extreme in areas, and could result in some heat damage:

“I don’t expect serious heat damage, and part of it is as you suggested, because soybeans have such a tremendous capacity to compensate for it.  we’ll probably get some weather, if the forecasters are right, that soybeans don’t particularly like.  And will too, some, in the afternoons, where they’re shut down instead of producing anything, and that’s certainly not going to help yields at all.  But, they’ve got pretty good capacity for compensating, and the net result may be no worse than the growing hours that we lost during the hot part of those days so we  may be alright, so soybeans may just demonstrate the capacity to tolerate hot, dry weather, they can do it again.”

Dunphy says disease pressure has been light, but insect pressure is a different story:

“Diseases, knock on wood, have not been a widespread problem, yet.  We’ve always got a few fields that have disease in them, and quite a few that we could show you what some of these diseases look like, if we looked real hard.  But, nothing has really gotten out of hand.

Insects are a different story, particularly the foliage feeding insects and corn earworm.  We’ve got some areas where corn earworm moth counts are pretty high, but they’re always spotty.  So, we kind of have to check those field by field, and make the decision to treat, field by field.  But, again, that’s fairly typical, especially in the Coastal Plain and Blacklands.”

The tropics are starting to heat up as they do this time of year, and just the right storm could make soybean rust an issue says Dunphy:

“That’s right.  It literally has been too hot, for rust to be happy, and that’s a good thing for us.  We don’t’ need rust coming in this early, it has the potential to defoliate a crop prematurely, and that, of course, has big impact on yields, doesn’t’ always do it, but it has the potential to do it.  if it comes in late, or not at all, we don’t have a problem, but if it comes in this early, we’d have a problem.  The closest rust we have, that we know of, so far, is in southern South Carolina, 200-plus miles from literally all of our soybeans in North Carolina, and 300 for most.   And for 300 miles out, I’m not too worried about them yet.”

But, should tropical activity come across the panhandle of Florida…

“The weather pattern that would cause us the most problem, the most likelihood of getting rust, would be if a storm came across the panhandle of Florida, and came up the east coast.  They’ve got rust spores in the panhandle of Florida on relatively high numbers this year, so if a storm came through there and came to North Carolina, that’d be a problem.

If it comes in off the coast, directly off the coast, that would be the least serious, because there aren’t many rust spores out there in the ocean.”

Dr. Jim Dunphy, NC State Extension Soybean Specialist.