Skip to Content

Row Crop Disease Update May 8th

By: Dr. Kemerait

Planting time is always a stressful period for growers.  There are so many tasks to be accomplished, from equipment maintenance and calibration to readying fields, from deciding on products to use for pest management to spreading fertilizer and applying herbicides. Planting times is simply tough on a grower.

For many of our growers, the 2020 planting season has been especially difficult.  There are the obvious things- commodity prices and uncertainties brought on by Covid-19.   The seed-quality issue on peanuts has resulted in significant angst among farmers as to how best to manage Aspergillus diseases- what to use and what to put in-furrow.  Secondly, the current May “cold snap” has many scrambling to adjust planting dates, timing of irrigation events, and use/choice of seed treatments and in-furrow products.  

Here are some thoughts:

1. By next Tuesday, we will be out of this cold snap. Until then, growers may (Or may not) change a thing about planting or irrigating or disease or nematode control, but they should factor weather conditions in to their plans; such may or may not affect decisions.

2. For control of seed and seedling diseases, soil temperature and soil moisture are critical factors. Cool wet soils increase risk to seed rots, and seedling blights to Rhizoctonia and Pythium, in large part because slowed germination and reduced vigor.  Hot and dry soils increase risk to Aspergillus crown rot on peanuts because the fungus likes hot and dry and because hot soils can damage and scald tender peanut shoots.

3. Our soils, even in this cooler period, are certainly warm enough for planting. But cool temperatures coupled with cold rain (tonight) or cold irrigation could cause problems.

4. By Tuesday, we will be back in warmer temperatures, but it looks like we won’t be “too hot and too dry” (we will be in Goldilocks weather). Neither “too not” nor “too dry” should REDUCE the threat of Aspergillus crown rot and early-season white mold on peanuts. But not eliminate risk.

5. I am expecting earlier out-breaks of soybean rust this year as the disease is already well-established in kudzu on the Coastal Plain.

6.  The impact of southern corn rust will depend on when we first find it.  We HAVE NOT found it yet.