Most everyone is looking forward to what the forecast has been calling for – more moderate temperatures and some rainfall over the next few days. It is never too late for rain. This potential rain could help finish out some cotton, peanuts, corn, milo, sunflowers, and help generate some pasture grass before winter sets in. Plus, I’ve seen wheat drills running throughout the area. It has been best for the crop to continue watering through this time, but hopefully any rains will help make the decision to shut it off easier.
The cotton crop is safe from most all insect pests, other than cotton aphids and stinkbugs. These two can linger some years till the bitter end. Aphids have been all over the board this month. In general, I am not seeing aphids as much this week as last, and stinkbugs have been mostly along field margins where they go back and forth between weeds in a bar ditch and then the field. I mentioned this last week, especially if we get this rain predicted, this is a good time to sample the soil for cotton root- knot nematode infestations. This will help determine level of management you will need to use next year. Cotton harvest is approaching.
Irrigation water is still going for most. I suspect if we receive a 1” or better rain many if not most producers will shut water off, with some exceptions. Just remember that a cotton boll can take moderate stress when it is 20 days old. Moderate stress is when the plant wilts in the heat of day but fully recovers after sundown. So, if we set the last harvestable boll around August 15th, that boll will be 20 days old this next Thursday ( 9/ 4). When that boll is 45 days old the plant can go into permanent wilt and not impact the quantity or quality of that boll. So, we want to keep moisture available to the plant through approximately September 29.
The cotton plant is still using nearly 0.2” of water per day for a few more days, and then it continues to drop over the next 3-4 weeks. If you receive a 2” rain the next few days that will keep cotton fresh for ~10 days. There is probably 3-5 days of moisture present in the soil currently from irrigation. Odds are between now and the 26th of this month we receive some additional moisture. I’m not saying we are definitely finished irrigating, because weather forecasts have been known to be wrong. Put your own pencil to these estimations for your situation. Oh, be aware that I am seeing verticillium wilt in some susceptible fields. That may help hasten shut water off also.
In peanuts Although I have been picking up on foliage feeding larva, I feel confident these will not amount to much at this point. The incidence of foliar disease has been fairly low this summer locally but has become much more concerning with this recent weather and forecast. Be careful about the development of leaf spot and other above and below ground diseases. The goal now is to maintain vine health and keep pods maturing out. I think we are still a way out from digging, but I would start scrapping hulls here over the next two weeks to see how it is progressing. Irrigate as needed to keep peanuts fresh until dug with little stress.
Grain sorghum ranges from nearing harvest on early planted to boot. Those acres which have not headed yet I would be extremely conservative on what I spend on those acres. It will be cutting it close to have time to mature out. I feel somewhat confident in those acres which are at or very near flowering that they have time and are worth protecting from sorghum aphids and the head worm complex. The change we are anticipating here over the next few days may also change the pest pressure. I am still concerned about sorghum aphids and so YOU MUST SCOUT! Sorghum midge on this late milo is also a MUST SCOUT on flowering sorghum. Those fields which are post-flowering need to also be scouted for head worms. I am also finding Lygus and stink bugs in sorghum heads as well. Consider them when and if you check heads.