West Plains
IPM Update


news about integrated pest management in hockley and cochran counties
Kerry Siders, EA-IPM
(806) 894-2406 (phone)
(806) 638-5635(mobile)
(806) 897-3104 (FAX)
E-Mail: k-siders@tamu.edu   http://lubbock.tamu.edu/ipm  
Vol. 7, No. 12
1212 Houston Street, Suite 2, Levelland, TX 79336
August 7 , 2002

IN THIS ISSUE:

* Crop and Insect Situation: Cut-out, cotton aphids, beet armyworms, cotton bollworms
* West Texas Ag Chem Conference

CROP & INSECT SITUATION
Figuratively speaking we are getting on the "short rows" now. Irrigated cotton across Hockley and Cochran counties has physiologically cut-out if not hard cut-out. Fields average 2.75 nodes above white flower (NAWF) as of August 6th. Some irrigated cotton fields reached physiological cut-out (4 NAWF) on July 20. If we use the current average of 2.75 NAWF, than those fields would have reached cut-out on about August 2nd. Using information generated by the COTMAN program, cotton will require: approximately 350 heat units (DD 60's) after cut-out to be safe from cotton boll weevils; 550 heat units (HU's)after cut-out to be safe from worms; and 950 (HU's) after cut-out for harvest aid application. Right now we are averaging 20 HU's per day. If we maintain that level of heat units through August, based on the average NAWF example above we should be safe from weevils (which have not hurt us so far this year) on or about August 19th ; safe from worms on or about August 29th; and be ready for a harvest aid application (using an average of 17 HU's per day) near September 29th.

This is definitely early cotton. Now understand this is just a projected estimation, particularly for harvest aid applications. Many scenarios can be played out between now and October.

Insect pest situations become more interesting by the day. On average cotton aphids continue to increase. Some of this increase can be attributed to pyrethroid flaring or other activities which have removed beneficials. Beneficials were doing a good job of holding many of these aphid numbers in check. See following tables for products available for aphid control.

Suggested Insecticides for control of aphids in cotton.

Insecticide
Formulated amount
per acre
Lorsban® 4E
8-32 oz
Bidrin® 8E
4-8 oz
Bidrin® 8E + Ovasyn® 1.5E*
4-8 oz + 0.67-1.33 pt
Bidrin® 8E + Curacron® 8E
4-8 oz + 2-4 oz
Provado® 1.6F
3.75 oz
Trimax® 4F
1.5 oz
Lannate® 2.4 LV
12 oz
Parathion 8E
4-6 oz
Curacron® 8E
8 oz
Centric® 40 WG
2 oz
1

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

 

Control of cotton aphids with various insecticides, RR2200, Rex Isom Farm, Idalou, Texas. 2000.

Average Number of Aphids per Leaf 1/
Treatment2/
0 dpt
5 dpt
% control3/
9 dpt
%
control
Intruder 70WP 1.1 oz
105.73a4/
1.30c
99.59
0.30c
99.08
Intruder 70WP 2.3 oz
147.90a
3.35c
99.32
0.53c
98.96
Bidrin 8E
5.3 oz
156.83a
142.47bc
64.19
4.57c
88.98
Bidrin 8E
8.0 oz
163.40a
68.73c
84.80
2.07c
95.61
Centric 40WG 1.9 oz
112.20a
89.20bc
79.70
3.70c
91.91
Furadan 4F
8.0 oz
97.03a
46.87c
86.66
3.13c
91.44
Provado 1.6F 3.8 oz
73.97a
148.33bc
28.77
12.93bc
40.37
UTC
------
402.00a
------
41.87ab
------
LSD (P=.10)
NS
152.465
30.965
P>F
0.1431
0.0082
0.0324
1/ Average of total number of aphids on five top and bottom leaves per plot.
2/ Treatments were applied with a CO2 backpack sprayer at 40 psi and 15 GPM.
3/ Percent control was adjusted using Henderson's formula.
4/ Means in a column followed by the same letter are not significantly different by ANOVA (P = 0.10 LSD).

Beet armyworms have become more prevalent the past week. Egg masses and young worms or hits have been noted in scattered fields. In some cases these will be of concern. Be careful to note what type of feeding damage is occurring from these beets. If it is mainly foliage the threshold is much higher (+20,000/acre), versus if they are damaging fruit particularly bolls than we use the same threshold as bollworms (right now 10,000 - 12,000 per acre). Below are labeled products for beet armyworm control. Call if you have questions.

Suggested insecticides for beet armyworm control

Product
rate/a
Lorsban 4E
1pt
Confirm 2F
4 - 16 oz./a
Larvin 3.2F
1.5 - 2.25 pts
Intrepid 2F
4 - 10 oz.
Steward 1.25 SC
9.2 - 11.3 oz./a
Tracer 4 SC
2.14 - 2.9 oz./a

Cotton bollworms have been continually active in many fields the past several weeks. A fairly significant egg lay again occurred starting the end of last week through the past day or so. Fresh white eggs are still easily found. Each field has been highly variable in the survival of these eggs and subsequent worm populations. That is why each field most be scouted on a regular basis. My threshold right now for those average fields at 2.75 NAWF will be 10,000 - 12,000 worms per acre. I have not seen any problems with any of the pyrethroids this year so let cost help you make the decision. If you have aphids at any level and armyworms in the mix as well call and we can go through the options for managing those situations.

West Texas Ag Chem Conference

August 28, 2002
Lubbock Memorial Civic Center
Pre registration prior to August 9 $50, After August 9, $70.0.

West Plains IPM Update is a publication of the Texas Agricultural Extension Service IPM Program in Hockley and Cochran Counties.

Editor: Kerry Siders
Production: Patty Castaneda


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