Texas Agricultural Extension Service
The Texas A&M University System
 
T-Y IPM NEWS

news about integrated pest management in Terry and Yoakum counties
Scott A. Russell, EA-IPM
Telephone: (806) 637-4060
Mobile: (806) 893-1041
Fax: (806) 637-2588
E-Mail: sarussel@tamu.edu   http://lubbock.tamu.edu/ipm  
Vol. 2, No. 7
209 South Fifth Street, Brownfield, TX 79316
July 12, 2001

General Situation:
Even with the hot, dry weather, irrigated cotton is generally doing well. Dryland fields are in need of precipitation. Plants where water has been short are "drawing down" in the afternoons. Scouting program fields range from third grown squares to bloom-boll. Most fields at first bloom have 7-9 nodes above white flower (NAWF). A few fields, where water has been limited, are in the 5-6 NAWF range. Square set rates are quite variable across the area. Most fields are in the 75% to 95% range, while a few are below 70%. There have been some of these fields with low square retention rates where we can not point to insects as the cause. Many are speculating about environmental and/or physiological causes for these low square retention rates, but no one has a definitive answer.

The most common pest this week continued to be cotton fleahoppers. Lygus are present in most fields, however not at economic levels. Bollworm eggs were found in most fields, but few worms are surviving. Aphids are present in many area fields at very low numbers. Area consultants report treating fields for fleahoppers, lygus and or bollworms during the last week. Beneficial insect numbers remain very high, even behind insecticide treatments.

There are plenty of beneficials in adjacent fields to migrate back into a field after treatment.

Assorted Plant Bugs:
Cotton fleahoppers numbered from 4 to 29 per one hundred terminals examined in scouting program fields. As fields begin to bloom the cotton plant can tolerate a higher number of fleahoppers, unless a less than acceptable fruit load is present. We recently put out a test to evaluate five products for the control of cotton fleahoppers. The following table provides the results after three days. Percentage control is the average of four replications for each product. The test plots in this evaluation were not significantly different in numbers of fleahoppers prior to treatment. Even though there appears to be considerable difference in the percentage of control between treatments after three days, these are not significantly different from one another. There was considerable variation in the raw numbers of fleahoppers present at three days after treatment, with one replication of some having very high numbers of fleahoppers present. This is not to say these products do not provide satisfactory control but rather that the test plots had more variation than expected. I will compare these more throughly and provide addition information in next week's newsletter.

Educational programs conducted by the Texas Agricultural Extension Service serve people of all ages regardless of socioeconomic level, race, color, sex, religion, handicap or national origin. The information given herein is for educational purposes only. References to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Cooperative Extension Service is implied.
The Texas A&M University System, U.S. Department of Agriculture, and the Commissioners Courts of Texas Cooperating
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Treatment Percent Control, 3 days
after treatment
Untreated Check 0
Leaverage 2.7 @ 3.0 oz/acre 85.0
FMC numbered compound 57.8
Captrue 2EC @2.6 81.3
Acephate 90SP @4.0 oz/acre -314.4
Centric @ 3.0 oz/acre 50.0

Western Tarnished plant bugs (Lygus) are present in most fields, although not often at economic levels. There have been many questions about other "plant bug" like insects. We have numerous scentless plant bugs and stink bugs out there. Most experts tell us that these guys are not pests. Although the green and Southern green stink bugs are later season pests in the Southeast. The scentless plant bug is not suppose to feed on squares and therefore should not impact square retention.

Worms:
While beet armyworms were virtually absent this week, we saw a few one day old bollworms. While none of the scouting program fields had economically damaging infestations there are reports from consultants and producers where treatments were needed. As we have more cotton blooming it will be important not to overlook those worms which might be within the flower or under the bloom tag. We now need to begin doing whole plant examinations to properly scout for bollworms. Tobacco budworm and bollworm moths are attracted to and lay eggs readily in cotton that is producing an abundance of new growth. Moths usually lay single eggs on the tops of young, tender terminal leaves in the upper third of the plant. Eggs are pearly white to cream color and about half the size of a pinhead. These should not be confused with looper eggs, which are flatter and usually laid singly on the undersides of leaves. Eggs hatch in 3 to 4 days, turning light brown before hatching. Young worms usually feed for a day or two on tender leaves, leaf buds and small squares in the plant terminal before moving down the plant to attack larger squares and bolls. When small worms are in the upper third of the plant, they are most vulnerable to control by insecticides and beneficial insects and spiders. Once worms have grown to larger than ½ inch long, natural and insecticidal control are less effective. Insecticides applied to control 1/2-inch long worms are only moderately effective. Sometimes moths deposit eggs on squares, bolls, stems and, in general, lower parts of the plant. We are seeing a lot of this activity at present.

Treatment may be justified when counts average 5,000 or more small worms per acre. However, if two or more key predators are found for each small worm, control measures may not be needed or a microbial insecticide may be used. The actual treatment level will vary according to the ability of the individual scout to locate small larvae, the age structure of the infestation, maturity of the crop and crop value. Under the present conditions, we should consider the current crop value before making treatment decisions.

With our high population of beneficial insects, don't make hasty decisions about which insecticide to use. Conventional insecticides often kill beneficial insects and spiders, thus allowing a rapid increase in bollworm numbers. Avoid making conventional insecticide treatments on the basis of egg numbers or the first signs of crop damage. Under most conditions, do not use conventional insecticides before blooms are observed in the field. Consider using a microbial insecticide or one of the newer chemistries to preserve beneficial insects and spiders. Products like Steward, Tracer and Larvin or the Bt type formulations would be good choices.

Turnrow Meetings:

Terry County Co-op Gin, Thursday, July 12, 8:30 A.M.

Fiber-Tex Gin, Thursday, July 12, 10:30 A.M.

Yoakum County Co-op Gin, Friday, July 13, 9:00A.M.

Terry and Yoakum County Peanut Field Day: July 26, 8:30 A.M. met at the Terry County Livestock Barn. Site visits to area test plots and discussions addressing current peanut research and production will be led by Texas Agricultural Extension Service personnel. 2.5 C.E.U.s will be provided and breakfast will be sponsored by Western Peanut Growers and Tokio Co-op Gin.

T-Y IPM News is a publication of the Texas Agricultural Extension Service IPM Program in Terry and Yoakum Counties.
Editor: Scott A. Russell
EA-IPM,
Terry & Yoakum Counties		 Production: Bea Pippin


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