CURRENT CROP CONDITIONS
The area cotton crop is continuing on schedule with most of the program fields well past cutout. The cooler temperatures during the first part of the week has made some of the stressed cotton look a little better, however, hot temperatures will return to the area on Thursday and Friday. Many of the area fields that are under limited irrigation or have experienced well troubles have undergone a dramatic boll loss in the last 10 days. Some of these fields have lost more than 80% of their bolls. Most of these were second and third position bolls and first positions towards the top of the plant. Insect pressure remains heavy this week, but most fields should be safe from worm feeding starting August the 24th. The COTMAN computer model is still saying that fields can be defoliated staring on September 4 through September 24 for all of our program fields. Keep in mind, these projections can change weekly due to temperature fluctuations.

WHAT THE SCOUTS ARE FINDING

Nothing much has changed since last week, except that bollworms are being found in most program fields in extremely high numbers. Every program field that we have checked this week has populations of aphids, beet armyworms and bollworms. Cotton aphids are still ranging from infestations located in the terminal and on squares of the plant to over 50 per leaf. Compared to last week, aphid populations as a whole are increasing in our program fields. Beneficial insects capable of knocking out these infestations are still hit and miss in most of our fields. We are seeing fields that have been previously treated for aphids starting to have populations increase towards economic threshold at the bottom of the plant.

Most of these "aphid problem" fields are very lush and the products were aerially applied and therefore never completely controlled aphids that were feeding inside the squares at the bottom of the plant. With hindsight being 20/20 we should have probably maxed out the rates of the aphid materials. My true concern is having these aphids still located inside the bracts on the lower portion of the plant and having to treat for bollworms. I can almost guarantee that many of you will have to retreat your aphids after this next bollworm run. Hopefully I will be wrong and the aphid situation is over, but do not count this pest out just yet.

Bollworm eggs are being found in most program fields and are ranging from zero to75,000 per acre. Larvae are ranging from 0 to 50,000 per acre. In fields that have reached cutout and have no squares and small bolls present, we are finding less than 5,000 worms per acre. In fields that have cutout and still have an abundance of small squares and bolls, we are finding bollworm populations of well over 15,000 per acre. Control decisions during this time of year are difficult for me. It can be extremely hard and sometimes foolish to walk away from 20,000 or more small worms per acre in a field that has little or no small bolls or squares present. In some cases I have seen this many worms crash with little or no damage inflicted to the crop. On the other hand, I have seen infestations of this magnitude destroy every boll from node 12 to 14 to the top of the plant. Most of the heavy worm infestations have been in lush fields that have a high yield potential. Most of these fields will utilize aerial application making coverage an issue. Therefore waiting an additional three to five days in order to recheck the field only to find a very high number of worms ½ inch in size or larger feeding inside of small bolls and squares was in my opinion too much of a risk. In addition, the COTMAN computer model is indicating that in most of the program fields, the bolls that will make most of the money will be safe from worm feeding on August the 24th.

Therefore, as many of you already know, I thought it would be in your best interest to treat these heavy infestations. The drawbacks to these treatments will be the lowering of the beneficial insect populations which will leave the door open to more beet armyworm infestations and the flaring of the ever constant aphid populations.

Beet armyworms (BAW) are still being found in every program field. As with last week, most of these infestations are light and are concentrated to very small portions of the field. We are however, treating at least one program scouting field per week for this pest. Maybe it is just my imagination, but we are finding larger and larger egg masses. I have a suspicion that some of these egg masses are Fall armyworm. The good news is that we are having no problems in controlling BAW. The most popular product being used is Intrepid. This product is providing both excellent control and residual.

Fall armyworms (FAW) are being found in a few program fields in and around the city limits of Lubbock and in Eastern Lubbock County up and down the canyon. Not that this is really a big deal with so many bollworms and in some cases BAW running around, but they are out there. This pest will feed on bolls and squares and I have not had any trouble controlling this pest with pyrethroids. The biggest problem that this pest gives me is identification of small larvae. I cannot differentiate 1st through 3rd instar larvae of FAW from BAW larvae. This point is really important when making chemical recommendations for control. I really do not have any data on the efficacy of Intrepid on FAW. In addition, the pyrethroids are cheaper but do not control BAW. Just one more little problem to mull over while driving to the next field.

Suggested insecticides for beet armyworm control

Suggested Insecticides for control of aphids in cotton.

Suggested Insecticides for control of bollworms.

* The synthetic pyrethroid insectidides recommended for control of bollworms also will control boll weevil. However, application intervals similar to those recommended for the traditional phosphate insecticides (3 to 5 days under heavy pressure) are necessary to provide adequate control. When treatments are to be made for a bollworm-boll weevil complex a suggested treatment regime is to use a pyrethroid followed 3 to 5 days later by a phosphate or carbamate boll weevil insecticide.

Posted at this web site by:
texagnet Internet Services.