Peanuts: Here are some reminders since the rain has really messed up some spray timings. Try to avoid making applications of Cobra or Ultra Blazer in the 60-80 DAP window. Prostko has recorded yield losses of 5-10% when applying these herbicides during that period. Normally we would apply a grass herbicide about 3 days before a fungicide because of the antagonism that occurs when the two are tank-mixed. However, if you’re in a bind, you can increase the rate of your grass herbicide by 5-10% to help overcome the antagonism. this will still not help with very large plants. You can apply 2,4-DB up until 80-90 DAP and it can be mixed with most fungicides. It’s not a savior spray because 2,4-DB doesn’t work well on weeds growing above the peanut canopy. Fungicides are tricky right now because some people have been out of the field for 2 weeks and some for 2 months. Keep in mind that there is no silver bullet and that each situation should be treated differently. Call me with your situation and we can figure it out. There are some keys to remember.
- Get a good fungicide or tank mix of fungicides on as quickly as possible-different scenarios call for different fungicides.
- Coverage is very important-you may have to use a plane but you will get better coverage with a tractor.
- Be aware that disease is probably already active in your field so we will have to be aggressive to protect the crop.
- We have fungicides with both protective and curative activity, so choose them based upon your current scenario.
Cotton: Cutoff day for Dicamba use is July 30th. Fertility leaching from all this rain has started to show up. Petiole samples (leaf stem) are a good “spot check” for troubleshooting fertility issues especially related to N & K and are usually taken after bloom has started. Tissue sampling (leaf) is good for detecting Sulfur and micronutrient (magnesium, manganese, zinc) deficiencies. For troubleshooting purposes, it is a good practice to take a sample from the good section and then one from the bad section. This will give us something to compare the results to.
Corn: Preharvest control for morning-glories is to apply Glyphosate+Aim within 3 days of harvest. This will not miraculously remove the morning-glories but it will desiccate them enough to harvest.