Volume XXVII No. 9 May 17, 2002 GENERAL SITUATION: Continued same old weather pattern. Burned up. Maybe some rain this weekend which could help irrigated farmers keep pace with what has been overwhelming demand for water by all the crops. Insect activity increased slightly in some fields. Irrigated Cotton Ok, but.... Cotton in the irrigated country appears headed for a reasonably good yield, but not record yields. The plants are small and are loaded with fruit. Some fields have many small bolls and plenty of blooms and squares to back up those bolls. But, more than just supplemental irrigation supplies will be required to make the crop keep going at the current rate. Salts have been observed on the beds where irrigation water has dried which is part of the reason for the smaller plant sizes. Additionally, the never-ending heat has put a further stress load on the small and/or fruit laden plants to keep them small. Only time will tell if enough irrigation water and rainfall will be adequate to make a good yield on some of the irrigated fields. Boll Weevils Active A few boll weevil punctured squares were reported from a small number of fields in the mid-Valley area this week. All punctures were located along field margins. The finding of weevil punctures this week is about on schedule with most previous years. Watch for increases as the weeks continue. Bollworm Activity Continues Bollworm egg and worm counts were very low again this week. Less than 1 egg and worm per 100 plants was reported in most fields. A single field report of worms and damage that required an insecticide application was reported this week. Beet Armyworms Beet armyworms were not reported to us this week. That does not mean that they do not exist, but that no one reported them. The current weather pattern still is favorable for beet armyworms, spider mites and aphids. Watch for them. Aphids Doing Well Cotton aphids increased again this week in many fields and spider mites continued to build in many fields along with aphids. Natural enemies like lady beetles and some lacewing larvae were observed to be building and aphid populations may crash.

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PEST CAST continued

Few parasitized mummies were observed in most fields this week. Check fields often for changing insect activity before making any insecticide treatment decisions.

Aphid Insecticide Test Results

We completed an insecticide test on cotton aphids this week. The results are shown in the attached table. Basically, all of the products tested did well against aphids and therefore offer producers who need an aphicide a good choice of insecticides for the job. We will conduct one more aphid count in the test plots early this next week to observe length of control. We will report same to you in the next Pest Cast issue.

Watch for Spider Mites

Spider mites increased in many fields this week. Mites appeared to increase in some fields and areas regardless if the fields had been previously treated for other pests. The hot and dry weather has contributed to the mites increase. Heavy rains could help reduce the mites, but experiences in past years show that if the mites are in heavy numbers, that rain alone may not be enough to put them out of business. Watch for what appears to be speckling on the upper surface of leaves where mites may be present. Their feeding activity causes the lighter specks on the leaves and are usually easy to spot. Mites may and have been observed feeding on both the tops and bottom surfaces of leaves. No numeric treatment threshold exists, but if mite colonies are expanding and webbing is beginning to occur where the mites are feeding, then a treatment may be necessary to control them. Since mites exist on both surfaces of leaves, most insecticides must be directed to where the mites live, if an application is going to have a chance of being successful. Spraying just over the top of the leaves with most of the insecticides will likely result in the mites on the undersides of the leaves escaping the treatment and resurging after the spray is over. Drop nozzles on ground machines are definitely in order so that more spray can be directed to the mite colonies in order to achieve better control.

Cotton Aphid Insecticide Test
TAES Hiler Annex Farm
Weslaco, Texas
Alton N. Sparks, Jr. and John W. Norman, Jr.
May, 2002

All treatments were made on May 9, 2002, with back pack sprayer using 3 nozzles per row at 10 gallons solution per acre. Silwet surfactant at the rate of 0.5% by volume was used with each of the insecticides.

Pest Cast Recipients:

Shortly after we sent out the Pest Cast issue this morning (Friday, May 17th), we received a report that a number of additional fields had treatable levels of bollworms across the LRGV, especially along the river and in the mid Valley area. We want to alert growers and others to the possibility that worms apparently have increased in some fields and that all fields need to be checked to determine if worm infestations are at treatable levels.

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