Texas Cooperative Extension

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July 9 , 2004

Anyone wanting this newsletter by e-mail please send me a note at w-ree@tamu.edu and I’ll put you on the list. If any one has had an address change from a rural route box number to a 911 address please let me know so I can make the change. I have had to drop several producers because of returned letters with incorrect/old addresses.

Rain, rain and more rain. Although not everyone in Texas has received excessive rain, many areas have. Here in Brazos county we have already reached our average annual amount. Excess rain and water logged soils are creating scab problems and overgrown orchard floors. In this newsletter I’ve also added a section on weed control which can be found in the Texas Pecan Handbook.

Pecan Scab: With all of the rain I’m including the section on pecan scab again. Pecan scab is still a major threat to pecans in many areas of Texas. Orchard floors are soaked and it will be awhile before equipment can get in the orchard.. Where scab pressure is high and orchards floors are wet, aerial application, although not as good as ground application is still a good option.

Fungicides labeled for pecan scab in Texas:
Abound (azoxystrobin)
Flint (trifloxystrobin )
Enable (fenbuconazole)
Enable 75WSP/AgriTin
Orbit (propiconazole)
Orbit45WP/Supertin 80WP
Propimax (propiconazole)
Super Tin (triphenyltin hydroxide)
Stratego (trifloxystrobin)
Syllit 65W (dodine)

*** Grazing restrictions also apply to fungicides.

Aphids: Blackmargined aphids populations have been building during the last part of June. These honey dew aphids attract a lot of beneficials such as lacewings, lady beetles and spiders. It is generally felt that it is best to leave these insects alone and let the beneficials help control populations.

Spittle bug: White spittle masses produced by immature spittle bugs and becoming obvious in many orchards. Although I have said insecticides are not usually needed for this insect, there are no real clear guide lines. Immatures which feed in the spittle masses can cause nutlets to shed. If a producer has a very light crop along with a high percent (> 50% ?)of clusters infested, then an application might be justified. However, if spittle masses are large, then the damage is already done, plus with large spittle masses there could be poor control. If an application is needed look at spot treating infested areas and using a selective insecticide. If spittle masses have dried this means the immatures have quit feeding.  (Photo:  Spittle bug spittle mass on nutlet)

Black pecan aphid: Watch for black pecan aphids in the interior portion of the canopy. BPA infestations can be found by looking for the characteristic yellow angular blotches. This aphid is generally appears later this month or in August.

Walnut caterpillar: I’ve received a few reports of walnut caterpillar activity. Watch for colonies ofthese caterpillars feeding on terminal foliage and masses of larvae molting on the trunk of mailscaffold limbs. This insect is easily controlled with several different insecticides. In urban areas or inareas where drift could cause problems I recommend insecticides containing Bacillus thuringiensis.

Spiders are important predators in pecans and probably don’t receive the credit they deserve. You can find additional information on spiders inpecans at the following web site: http://pecanspiders.tamu.edu

Mechanical Tillage:
Advantage: Destroys all weeds and grasses.
Disadvantages: Requires a relatively high horsepower tractor; opens erodible sites to soil loss; can’t be used efficiently with surface low-volume irrigation systems; causes maximum soil compaction.

Advantages: Destroys all weeds and grasses; in-and-out types can work very close to trees.
Disadvantages: Requires high horse power tractor; opens erodible sites to soil loss; can’t be used efficiently with surface low-volume irrigation systems; high speed vertical rotation tillers damage soil structure and cause maximum soil compaction.

Mower - Rotary, sickle, flail
Advantages: Allows control of weed and grass growth while still maintaining sod cover on the orchard floor; sod cover allows maximum orchard access under adverse conditions.

Chemical Applicators - Hand pump sprayers
Advantages: Can be used to spray close to small trees
Disadvantages: Inefficient and unwieldy because the applicator must repeatedly stop to pump the sprayer; Must have coarse spray tips that are chemically inefficient; can’t be calibrated. Should not be used with preemergence herbicides.

Back Pack Sprayers
Advantages: Can be used to spray chemicals close to small trees; can be calibrated to apply both preemerge and contact chemicals; enables applicator to spray continuously without stopping to pump up pressure.
Disadvantages: Physically tiring since applicator must carry the dilute spray mix.

Controlled Droplet Applicator
Advantages: Utilizes a concentrated chemical solution and enables the operator to cover a relatively large area on foot without carrying much weight.; weeds are killed with maximum chemical efficiency, especially when applying glyphosate.
Disadvantages: Spray pattern is barely visible and easily moved by wind and extra caution must be used when applying chemicals near small trees with low foliage

Controlled Droplet Applicator - Tractor
Advantages: Weeds are killed with maximum chemical efficiency; they utilize an concentrated chemical solution and cover a relatively large are with a minimum of spray solution; they need only low-output, low pressure equipment, units can be rigged to lawn tractors, 4-wheelers or other small carriers. Disadvantages: The spray pattern is barely visible and moved by the wind; units are not well suited for wettable powders or for application of most preemerge herbicides; this low volume low pressure small droplet technology may not provide adequate coverage of taller weeds and grasses.

Boom Sprayer - Tractor mounted
Advantages: These types of rigs are the most versatile with any type of herbicide can be applied accurately and effectively; relatively low output, low pressure equipment is needed.
Disadvantages: These units are primarily used as dilute spray applicators and require more water per acre; even at low pressure, smaller spray tips may have considerable droplet atomization, atomized droplets drift readily and present a hazard in close work around vulnerable crops with low vegetation.

I hope all of you will be able to make it to the annual TPGA Conference and Trade Show in San Antonio this year. Call the TPGA office 979-846-3285 or visit their web site at www.TPGA.org for more information. I will have an exhibit booth again this year and hope you will come by to visit.

Also this is a reminder that CEU credits will be given during the conference and you will have to sign up each day. Announcements concerning sign up location and CEU credits will be made each morning.

July is the month to take leaf samples. Leaf sample analysis along with soil samples will provide you with a good picture of your fertility program. I’ll provide more information on this topic in the next newsletter.

Also in the next newsletter will be information on herbicides.

July 11-14, 2004
83rd Annual Texas Pecan Growers Conference and Trade Show
San Antonio, TX
Contact: TPGA - 979-846-3285

For more information, contact:
Bill Ree
Extension Program Specialist
Texas A&M University-Riverside Campus
Bryan, TX 77806-2150
Phone: 979-845-6800
Email: w-ree@tamu.edu

The information given herein is for educational
purposes only.  References to commercial products
or trade names are made with the
understanding that no endorsement by
Texas Cooperative Extension is implied.

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