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. 13
1212 Houston Street, Suite 2, Levelland, TX 79336
August 14 , 2002

IN THIS ISSUE:

* Crop and Insect Situation
* Area Farm Bill Meetings

CROP & INSECT SITUATION
Grain sorghum continues to make progress in most areas, particularly those acres which received some much needed rainfall this last weekend. With many acres exerting a seed head or developing seed keep close watch for head worms (aka corn earworm, aka cotton bollworm). I would suggest intensifying your scouting for greenbugs and sorghum midge as well.

Area peanuts in most cases have some of the best yield potential we have seen in a couple of years. Currently no insect pests have been noted. However, keep shaking plants to monitor for worms. Six to eight per row foot can cause sufficient damage to warrant treatment. We have seen an increase of the incidence of leaf spot and rots. Of course the weather plays the biggest roll right now on how much these disease concerns progress. Understand that you must take a preventative stance with disease especially when symptoms are already present and the weather is conducive (wet and moderate temperatures). But also understand that most peanuts begin to deteriorate in plant health the closer we get to harvest.

Cotton of course is on the mind of most producers. A majority of irrigated and dryland cotton acres is beyond physiological cut-out (less than 4 nodes above the uppermost first position white flower or NAWF). In fact based on data from our scouting program fields, which stretch from Ropesville to Anton and west to Griffith and back south and west of Morton, the average NAWF is 1.3 with a range of 0 to 2.5 NAWF. If you have younger cotton than this understand that the probability of producing a harvestable boll from a white bloom on August 10 went to below 50%. The period of August 20-25th is what we would consider the last date a bloom might result in a boll which might contribute to yield. I know we have been spoiled by exceptional falls the past several years, and hope that this year holds the same for many of you who need it this year. However, I just caution you about spending money on protecting something such as a small squares which may not return the dollars.

The scouts and I continue to find bollworm eggs and larvae, cotton aphids, lygus, beet armyworms and their egg masses, cabbage loopers, yellow stripped armyworms and fall armyworms. Most fields (60%) remain relatively clean and will probably escape any treatments for this year. However, the other 40% has already been treated or is real close to needing to be treated. As I have stated before because of the highly variable pest complex and their population counts it is extremely important to scout each individual field. For me to make a blanket statement right now about the pest situation would do you an injustice.

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Suffice to say that there are fields out there with some very serious problems which require immediate attention with a crop protection chemical. Yet, on the other hand looks can be deceiving. Many factors should be taken into consideration before treating some of this mature cotton.

Speaking of mature cotton and money - I encourage you to be thinking ahead about budgeting for harvest aids.

Cabbage Looper
Cabbage looper eggs are laid singly, mainly on the lower surfaces of leaves. Larval feeding damage is characterized by leaf ragging or large holes in the leaves. Looper larvae often are killed by a disease before economic foliage loss occurs.
Management and decision making. No economic threshold has been established for this pest. Insecticide treatments generally are not recommended.

Beet Armyworm
Beet armyworm eggs are laid on both leaf surfaces in masses covered by a whitish, velvety material. Young beet armyworms "web up" and feed together on leaves, but eventually disperse and become more solitary in their feeding habits. Larvae skeletonize leaves rather than chewing large holes in them. Damaging infestations sometimes develop late in the season when beet armyworms also feed on terminals, squares, blooms and bolls. Several factors can contribute to these late season beet armyworm outbreaks. These factors are: mild winters (e.g., absence of prolonged freezing temperatures); late planting; delayed crop maturity; heavy early-season organo-phosphate or pyrethroid insecticide use; prolonged hot, dry weather conditions; presence of beet armyworms prior to bloom; and weather conditions that support long-distance migration. Additional characteristics of high risk fields that consistently appear to fit a pattern for developing beet armyworm problems are: sandy and droughty soils; skip-row planting; fields with skippy, open canopies; drought stressed plants; and fields infested with pigweed. The likelihood of a heavy outbreak increases as more of these factors occur in a given location.

However, when beet armyworm populations are high all fields are susceptible. When beet armyworms begin to damage the fruit, control may be justified. Infestations usually are spotty within a field, and careful scouting is necessary to determine the need for, and field area requiring, control. Beet armyworms longer than 1/2 inch may be difficult to control.

Management and decision making. Scout the field using the Whole Plant Inspection Method described in the bollworm and tobacco budworm section. Early Detection Threshold (Hatching Egg Masses); from initiation of squaring to cutout, if 2 "active hits" (i.e., recently hatched egg masses with actively feeding larvae) are detected per 100 row feet and conditions are optimal for a beet armyworm outbreak, treatment should be considered.

 

Remedial Threshold (for advanced infestations during mid season): when infestations are mainly leaf feeding and small worm counts exceed 20,000 per acre and at least 10 percent of the plants examined are infested, control may be warranted. If beet armyworm larvae have shifted from feeding on foliage
to feeding on squares, blooms and bolls, thresholds should be lowered toward the bollworm threshold of 10,000-12,000 small larvae per acre. When cotton matures and square feeding is of no consequence, thresholds should be raised to 20,000 small larvae per acre.

AREA FARM BILL MEETINGS
A series of meetings has been scheduled to assist producers with decisions concerning determining their bases and yields. The current deadline for these determinations is August 31st. Contact County Ag Agents Chris Edens @ 894-3159 or Jeff Wyatt @ 266-8858 .
AUGUST 19th Whiteface - Community Bldg 9 am
AUGUST 21ST Levelland - County Fair Grounds Womens Building 10 am
AUGUST 21ST Morton - Activity Bldg 2 pm
AUGUST 22nd Ropesville - Busters Gin 10 am


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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