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. 14
1212 Houston Street, Suite 2, Levelland, TX 79336
August 21 , 2002

IN THIS ISSUE:

* General Situation-Cotton, Peanuts, & Sorghum
* Upcoming Meetings

CROP & INSECT SITUATION
A good rain fell in portions of Hockley County and most of Cochran County. This should make decisions on any side-roll systems much easier to finish up. For center pivot and drip it will be a case by case situation. Those areas in Cochran which received up to 1.75" of rainfall you may want to take "a wait and see" approach. Depending on the maturity of a field, the temperatures we receive this week, and what the forecast for the next 14 days holds will be important. Just do not error on the side of too wet. \ This will cause regrowth, make harvestable bolls vulnerable to insects longer, and delay maturity. For those fields which received less than 1 inch of rain you will probably need to continue to spoon field some irrigation water through at least the end of the month. Call if you need help bouncing off some thoughts about what to do.

Boll rot has been noted in more and more cotton fields. Cotton bollworm activity went out the roof this past week. Beet armyworms and cabbage loopers have complicated factors. A few headworms have been noted in grain sorghum. Greenbugs are being held in check by beneficials. Peanuts need to be scouted for worms, rot, and leaf spot.

COTTON
A majority of the cotton crop in Hockley and Cochran counties has an average of 0.7 nodes above white flower (NAWF) with a range of 0-3.5 NAWF. Based on actual heat unit accumulations, from National Weather Service observer data, the cotton acreage which cut-out (< 4 NAWF) prior to August 2 (90% of fields) has accumulated over 360 heat units (DD-60's). These acres should be safe from cotton boll weevil damage (which I have not seen so far this year by the way) to this years crop. This also tells us that we need about another 190 heat units to be safe from worms. With the current average of 19 heat units per day it will take approximately 10 more days and we should be "out-of-the-woods" as far as worm damage to harvestable bolls.

Cotton bollworm moths arrived en masse the first of last week with the north winds. Especially hard hit was west of Morton to the state line. In other areas the more "growthy" cotton has been receiving the most pressure and allowing for survival. Bollworm egg lays were seen as high as 75,000 per acre last Wednesday through Friday. Bollworms were noted in the 40,000 per acre range. Bottom line is if you did not heed my advice in the last issue to intensify your scouting in each individual field than you probably missed the big run. The past few days pressure has tapered off. The threshold which should be applied at this time for worms is 10,000-12,000 per acre.

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Beet armyworms and cabbage loopers are highly variable now from field to field. Also complicating this is the fact that yellow stripped and fall armyworms can also be found occasionally. The important thing is to make note of what kind of feeding damage these worms are doing. If they are damaging bolls than it should be lumped in with the bollworm counts for threshold consideration. The selection of a chemical or chemicals is the next step. This is where I would say get the advice of a professional. If you call me I will want to know the stage (nodes above white flower) of the cotton, number and size of the various worms, type of damage, are aphids present, and yield expectations. Call if you need help.

Cotton aphids continue to be found. Some fields continue to hold at low numbers, some slowly increasing and many which have been high (40-60 per leaf) for a couple of weeks have been either crashing or beneficials finally got the upper hand. We continue to find banded wing whiteflies in some fields, but not at treatable levels. Lygus have increased dramatically the past several days. This is possibly due to fields and their margins being cleaned up of weed hosts. Lygus damage to later cotton should be watched closely. Stink bugs and leaf footed bugs have also been numerous in some fields.

Cotton Boll Rot
Xanthomonas boll rot has been noted in several fields over the past month. This disease results from the same bacterium noted on foliage all season from bacterial blight. In the boll -rot phase of bacterial blight, lesions on bolls tend to be circular, dark green, and water-soaked or greasy when young. Two or more lesions often become confluent. Spots rapidly become sunken, brown, and dry in the center with a dark-red margin, and attain a diameter of about 3/8 inch. The causal agent, Xanthomonas compestris a true parasite, but is an exception to the rule that true parasites can breach the unbroken cuticle of the boll. X. campestris does, however, penetrate stomata, or enters through nectaries; it is conveyed by spattering droplets of rain, or carried by insects. Once within the boll, the bacteria multiply rapidly, killing and causing collapse of tissues, and spreading through the mass of developing fiber. Affected locks fail to fluff out. This results in spots of yellow fiber that may cause reduced grade.

 

 

The wet weather this week will definitely help spread this this disease. Make note of fields which have boll rot and note the variety. Certain varieties are more susceptible and it can be transmitted by seed.

PEANUTS
Peanuts need to be scouted immediately for worms. Remember 6-8 per row foot may cause significant amount of damage to warrant treatment. I have noted problems mainly on later planted fields. Also, keep close watch for late leaf spot and rots to pods. The weather is conducive for concern to prevent these problems.

SORGHUM
Sorghum pests have been relatively light on early- planted milo, more activity has been noted in late-planted milo. Continue to check for headworms, greenbugs, and midge. Beneficials remain fairly high.

REMEMBER
This is a good time of year to sample soil for nematodes. This can help with next year's decisions about at -plant nematicides.

UPCOMING EVENTS

August 28th - West Texas Ag Chem Conference, Lubbock
September 14th - Farm & Home Show Hockley County, Levelland
September 17th - Farm Fair Cochran County, Morton


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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