As parts of Indiana have gotten more rain over the past few weeks, but the bad news is that tar spot is now more likely to show up in corn.
“I think the main problem is how detrimental it’s been the last couple of years,” says Chad Threewits, an agronomy service representative with Syngenta based out of Wells County in northeastern Indiana.
He says tar spot is increasingly becoming an issue affecting corn yield.
“[In] previous years, it was just spotty across the state with a few fields really having a lot of problems,” says Threewits. “Last year, we saw throughout the whole summer this large increase of the amount of problems it really did with yield [and] with standability.”
Threewits says the rain that has been more prevalent over the past few weeks across Indiana may cause tar spot to pop up late in the year.
“With the amount of rainfall we just had, it takes about 14 to 21 days to start this cycle, so tar spot can start reproducing in our field, so it’s a great time to be out looking. Especially [since there was] a little later planning, we really expected to see it a little later this year. Now, with these recent rainfalls, we really can assume that we’re going to start seeing it in many parts of the state,” says Threewits.
He says there’s no hybrid or solution to completely get rid of tar spot, but fungicide applications can help.
“Those products work really well on tar spot,” says Threewits. “However, we’ve learned that they have a limited residual also, so it’s really understanding timing. Timing is a big one that we learned after last year. Just because we think we know everything on a disease, we learned [really quickly] last year that this disease came in for a long time and timing really made that a challenge. Whether it was an airplane application trying to get a sprayer across that field, there was just a lot of acres and a lot of logistics that we learned it’s hard to get everything done all at one time.”
Threewits recommends a fungicide from Syngenta to tackle tar spot.
“Our lead product that we really saw nice benefits was Miravis® Neo fungicide. [It has] three active ingredients. All [of] those having activity on tar spot, but also other diseases. In this dry year, we’ve seen a lot of benefits with just plant health, so helping that plant get through some of these stressful times. All of those things [will end] up with protecting our yield going into this fall.
Click BELOW to hear C.J. Miller’s report on how recent rains may increase tar spot in Indiana’s corn.