Been receiving a some calls over the past few days about when to plant / planting considerations for cotton and peanuts. Our target soil temp at the 4″ soil depth is 65 degrees F. Thinking about cotton timing makes me think about disease prevention and planting out of the threat of thrips….a moving target. I understand most have enough acres that y’all just have to rock and roll. Some more thoughts on this subject of planting and its timing from Dr. Bob Kemerait:
“Here are the things in my wheelhouse you get one best chance to battle BEFORE the furrow is closed:
- Seedling diseases in all crops (more on this throughout the week).
- Nematodes in all crops. (Yes there are some options, e.g. in peanut, later, but the BEST options are selected BEFORE the furrow is closed.) (variety choice and use of nematicides)
- Management of Cylindrocladium black rot (CBR) in peanuts. (Proline in-furrow)
- Management of Bacterial Blight in cotton. (variety selection)
- Possibly management of Cotton leafroll dwarf disease (planting date?)
- Tomato spotted wilt of peanut (Peanut Rx: https://peanuts.caes.uga.edu/extension/peanut-rx.html. About to be updated.)
- Diplodia collar rot of peanut (both the seedling disease form and the hand-in-hand form with TSWV)
When it comes to managing seedling diseases in cotton, – wait for the cooler weather over the next few mornings, and the high probability of rain on Saturday, to pass [if you can]. It is supposed to dip into the lower 40s in T-town [and Crisp Co] this week.
SEEDLING DISEASES IN COTTON are typically more severe during cooler and wetter weather. Why? Primarily the cool, wet soils slow germination and slow growth and development of the seed and seedling. Slow germination and emergence coupled with low vigor early on gives our most important seedling disease pathogen of cotton, fungus Rhizoctonia solani, the chance to attack and cause significant stand loss.
NOTE: Rhizoctonia almost always causes post-emergent damping-off seedling disease. Plants come up, kind of look ok, then buckle at the knees and die – or they just stay small and fail to thrive. Dig the plants up and you should see a beautifully diagnostic lesion just below the soil line. If the plants NEVER come up, you may have Pythium.
To minimize risk to seedling diseases: 1) avoid planting in cooler and wetter conditions are imminent, 2) make sure you have the best quality seed (ask conditions); smaller seed is sometimes prone to greater stand problems than is larger seed, 3) insure a good fungicide seed treatment package, and 4) if you are worried about higher risk to seedling diseases, consider additional treatments.
Additional treatments for cotton include 1) additional, higher-end seed treatments, and 2) liquid in-furrow fungicide. Neither additional treatment is a “general recommendation” for me as our standard cotton seed treatments are adequate to protect stand much of the time. However, when in doubt, additional treatments are good “insurance” against seedling disease, especially use of azoxystrobin (6 fl oz/A) in-furrow against Rhizoctonia.“