SC Corn/Cotton/Soybean Disease Update – 6/7

June 7, 2022

I am sure that many of you get various forms of information from other states. Dr. Kemerait in Georgia is very good about sending out updates several times a week, and I am sure there are other specialists who do the same.

I thought I would try to send out what we are seeing primarily south of the lakes. However, like Bob’s Georgia information is often an early warning for South Carolina, I hope what I see and send out will be an early warning system for the rest of South Carolina.
I welcome any input any of you want to share with the other agents.
I would be happy for you to share this information with your growers. But it is probably best if you reformat it as coming from you.

Foliar diseases: As dry and hot as it is we are not seeing a lot of foliar diseases. Most sprays should be made close to tasseling depending upon disease pressure and weather. Emphasis currently would be on spraying irrigated corn. I will send out the “Fungicide Efficacy Table” in a separate email this week.
They are seeing Southern rust in corn in Georgia near the Florida border in Grady and Wayne Counties. Southern rust can build and spread very rapidly even in hot dry weather. We often have wind patterns that would blow fungal spores from South Georgia to South Carolina. As of today, we have no reports of southern rust on corn in South Carolina.

It is still a little early to worry about spraying any soybeans for foliar fungal diseases. Normally we would wait on a field-by-field basis until soybeans are blooming before considering spraying. The exception might be if you see target spot earlier in the year.
Soybean rust: In a few weeks the Soybean Rust Newsletter will return under the capable management of Croft & Varn. Can anyone possibly beat Joe to having the first rust find ON SOYBEAN in South Carolina and end his 5- year streak? The Georgia folks have found Asian soybean rust near Valdosta in Lowndes County ON KUDZU. We have not seen that yet, but I don’t think we re looking very hard yet.

Many cotton growers struggled to get planted this year and the crop is now struggling with heat and drought.
In the past we have not had nearly as much target spot or aereolate mildew as they have seen in Georgia. I think much of this is because they are farther south in a different weather pattern, and they have a longer growing season in South Georgia. Most fungicide spray programs start at flowering and many strongly suggest 2 sprays. We have had limited responses to fungicide sprays on cotton in the past.

If you see any foliar diseases, especially on corn let us know. We can share your information with everyone or feel free to mail it out on this list. Likewise share some nice pictures of diseases if you have a chance.