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, though some crops may not benefit for this year. This potential rain could help finish out some cotton, peanuts, corn, milo, sunflowers, peas, and help generate some pasture grass before winter sets in. Plus, I’ve seen some wheat drills rolling to the north of us. It has been best for the crop to continue watering through this heat, but hopefully any rains will help make the decision to shut it off easier come mid-week next.
The cotton crop is safe from most all insect pests, other than cotton aphids and stinkbugs which can linger some years till the bitter end. I am not seeing aphids as much this week as last, and stinkbugs have been far and few between as well. 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 infestation. 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 will begin to 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 12th, that boll will be 20 days old this Sunday. 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 25. 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 (if that is your prayer) 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 finished irrigating. Put your pencil to it.
In peanuts I am not concerned now with foliage feeders or other insect pests. The incidence of foliar disease has been very low this summer but has become much more concerning with this recent weather. Be careful about the development of leaf spot and other above and below ground disease. I have seen some onset of black hull here this week. Understand, there is not much one can do about this. 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 only as needed to keep peanuts fresh until dug with little stress.
Grain sorghum ranges from nearing harvest on early planted to just near 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 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 in weather here the last few days may also change the pest pressure. I am still concerned about sorghum aphids, but they just do not seem to be getting out-of-hand (that is a technical term) in these later fields like we would normally expect. Trust me though, do not turn your back on them, and YOU MUST SCOUT! Sorghum midge have not been that common on flowering sorghum. This late grain is prime candidate though for midge. Those fields which are post-flowering need to also be scouted for head worms. I am also finding occasional Lygus and stink bugs in sorghum heads as well. Consider them when and if you check heads.
Call if questions on scouting, threshold, and treatment options. ***** West Plains IPM Update is a publication of the Texas A&M AgriLife Extension Service IPM Program in Hockley, Cochran, and Lamb Counties.