Fields have been making great progress in the heat this week, even the late ones. As we moved through the week, we found more open bolls consistently and consistently fewer cotton insects until most of our cotton scouting was just making sure the fields were not at risk from the usual suspects and covering late agronomic needs.
For all but a few cotton fields, harvest aids will be the next major consideration, and that concern is almost upon us already. There are still plenty of pest concerns in our late corn and sorghum fields as harvest is well underway for our earliest planted grain fields.
Drought creeps back into our lives just as we start preparing for wheat planting and try to finish fields out.
As of this week we only have a couple of really lush and rank fields that are not at absolute cut-out. These fields are a deep concern with an unknown freeze date looming. These fields were already pretty well-watered that had the misfortune of having locally heavy rainfall of 3-5 inches at inopportune time keeping them overly lush.
Even though irrigation has been off for several weeks, these fields just will not shut down and will need special attention as we face harvest aid season right around the corner. Meanwhile just a few miles away we have dryland that is so dry that they are being turned into insurance as drought disasters that have not seen a drop since early July after getting off to a solid if not late wet start.
On the whole, most of the fields that I felt would need special attention and conditioning to have any chance of being harvest ready in time look to be fine baring a very early freeze thanks to the conditions these past few weeks.
It has been almost a week since we found a bollworm egg or worms in our PPM cotton. There are also very few fields I feel worms or Lygus could damage from this point on. That being said, I am still noting eggs and young worms establishing in corn.
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There is a chance that on the lushest of cotton this next week, worms could establish on fruit that has little chance of making and develop into a large enough worm to damage harvestable fruit. I suggest if you have any field falling into this category, we continue to scout just to make sure.
While I feel worms and Lygus will not be bothering 90% or better of our cotton for the remainder of the year, I do intend to give a bit more scouting time devoted to pests this harvest aid season starting very soon. There are two reasons for this:
1. Stink bugs. The stink bug population in the area has been much higher than ‘normal’ in our area this year. While we have not treated any in the area I am aware of, these pests are highly mobile and have proven to congregate on older bolls causing either boll rot or hard lock. I intend to continue getting a few drop cloths and pay close attention to cotton during my first few weeks of harvest aid evaluations.
If, for whatever reason, I feel any field is at risk for stink bugs, we will be initiating boll dissection to determine if the damage being caused will be economic. This scouting technique for stink bugs is com-mon for our friends farther south where stink bugs are an annual issue and can be found on page 16 and 17 of our Managing Cotton Insect in Texas guide.
2. Cotton aphids. Aphids are a potential pest in late season cotton from honey dew accumulation on cotton lint and open bolls. Our threshold is around 12 aphids per leaf. We have had an unusually high population for aphids over the last month considering there were few bollworm treatments made.
This population was generally light with a few exceptions and has mostly been controlled until aphids are now hard to find. With cooler nights, late fertilizer applications made, and beneficials leaving fields for the next potential buffet, aphids could easily resurge.
Corn and Sorghum
Our oldest corn has been drying down for harvest for 2 weeks now while our youngest reached early dough this week. The oldest of our late planted corn should be seeing silage cutters moving their way as I write this. Disease, namely Southern rust, was again our largest concern this week.
Over the weekend last week, several fields entering dent increased in disease coverage by jumping 20% higher from the previous 25% coverage last week. We could not allow this damage to increase, even this late in crop development and three fields were treated. In most of our other fields this, and other, corn diseases are harder to find.
Spider mites are still in most fields, but seem to be loosing ground to beneficials and mite diseases. We did note some two-spotted mites moving in some fields in a few spots. These pests will generally move from top down, as opposed to the Banks grass mite that moves from lower leaves up. Other corn pests were very hard to spot this week.
Our oldest sorghum is at black line and drying down for harvest while our youngest is just now in a very late bloom but we have fields in most stages in between. The sugarcane aphid populations still seem to be crash-ing in our fields and not returning. This does leave several of our sorghum fields as ‘untreated’ for the year.
Headworms were very light in our sorghum fields this week as predators move up the plant from cleaning up treated or sub-ET SCA providing control and our limited worm populations seem more attracted to late corn. Midge are still an issue for any field still in bloom. Several of our latest fields were found with treatable populations of midge this week.
Our highest midge population came in at 1.38 midge per head. Lygus are very common in our sorghum, especially once the grain starts to show color. Our best ET estimates hints show that there should be about 12 Lygus per head. Our highest fields came in at around 7 per head with most having less than 3.
Stink bugs remain a common find, but also not near economic levels. Banks grass mites are in most fields, and moving up the plant, but this is most likely due to heat stress rather than damaging populations. Several of our lower input fields that are moving into hard dough are struggling in the heat.
Some pockets, especially the pockets that once held higher SCAs, might be sacrificing some stalk integrity to finish out their grain. A light water in-vestment in the high heat might be recommendable in these situations if possible.