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TEXAS PECAN GROWERS ASSOCIATION
March 17, 2004
Anyone wanting this newsletter by email please send me a note
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.
It’s hard to believe but another season is upon us.
From the comments I have heard from producers everyone is
expecting a good season. Some areas of the state had poor
crops last year because of a couple of spring freezes and
these orchards should have an on year. Lets just hope mother
nature will help us out.
For those producers that observed phylloxera infestations
last year this is a reminder that insecticide applications
for this pest are applied just after budbreak. Recommended
insecticides include: Provado 1.6F (imidacloprid) @ 3.5-7
oz/A; Lorsban 4E (chlorpyrifos) @ 2-4 pts/A; and malathion
57% EC @ 1-2 pt per 100 gallons. Livestock grazing is only
permitted with malathion. Since phylloxera infestations can
be spotty, spot treatments of trees that had galls last year
would be recommended.
I have written this section several times in the past but
since I generally receive a few questions each spring on
the use of “dormant”oil I thought I would rerun
this information on some of the basics of horticultural
Horticultural oils have been used in agriculture for over
a 100 years to control various soft bodied insects such as
scale, aphis, and mites. Horticulture oils can be used on
pecan but because pecan and ALL members of the Carya (hickory)
genus are considered oil sensitive, the use of any oil on
pecan is restricted to the dormant season. A few other species
of trees that are considered oil sensitive include: black
walnut, junipers, cedars, redbud and maples to name a few.
Horticultural oils control insects either by penetrating
the insect egg and interfering with metabolic processes or
by preventing respiration through egg shells or the respiratory
passages of mature or immature insects. Horticultural oils
have no residual activity so only those insects which are
coated will be controlled.
Technology in the refinement of oils has come a long way
since the use of engine oil emulsions. Today horticultural
oils are refined to certain specifications and can be used
on a wide range of plants.
There are several types of horticultural oils on the market
today which can cause some confusion. In addition, labels
on horticultural oils will contain a different terminology.
Not all horticultural oils are the same and an understanding
of label information is necessary to know the difference.
The following is a brief description of different types of
oils and an explanation of some of the information that should
be found on the label.
Dormant Oil: This class of oil is the heaviest
of the horticultural oils and is formulated for use
on dormant plants only. Apply these oils as late in
the dormant season as possible but before budbreak.
Dormant oil effectiveness increases as temperatures
increase and insect metabolism is accelerated.
Summer Oil: Summer oils are slightly lighter
than dormant oils and are formulated for use during
the spring and summer on some plants.
Superior Oil: This class of oil is the most
highly refined of all the horticultural oils. These
oils are used primarily during the growing season,
however, they may be used as a dormant oil by changing
When purchasing a horticultural oil it is important that
you understand the information on the label. The following
information should be on the label and will assist you in
determining the quality.
Unsulfonated Residue (UR): this number is
a measure of purity or degree of refinement and is
always listed as a percent with 92 being the minimum.
The higher the percent the higher the purity.
Viscosity: This is a property used to define
oil heaviness and is expressed in seconds. Horticultural
oils fall into the 60 to 200 second range, with the
heavier oils rating 100 or higher. The higher the number
the more persistent the oil on the plant. Dormant or
semi-dormant plants will tolerate heavier deposits
than trees in leaf.
Distillation: distillation temperature range
is a measure of the volatility of an oil. Horticultural
oils have a distillation range of 400 to 488 F. The
lower the distillation temperature the quicker the
evaporation. Dormant oils will have a distillation
range of around 438 F while superior oils will be around
Gravity: This is another method of weighing
oil. When related to viscosity and the UR it can provide
an index to oil paraffinicity. Oils should be largely
paraffinic to be safe for plants. Gravity is measured
in degrees and the higher the number the more paraffinic
the oil. Thirty degrees is the minimum standard.
Horticultural oils are an effective and safe way to control
scale on pecans. In Texas, dormant oils are permitted in
the Texas Department of Agricultures certified organic production
(Organic Food Standards and Certification, Texas Administrative
Code, Title 4, Part1 Chapter 18).
As I stated above, pecan is considered an oil sensitive
crop therefore only dormant oils are recommended. Before
purchasing and applying any type of horticultural oil ALWAYS
READ THE LABEL. When applying, make sure there is good agitation
in the tank. Even though you are making an application to
a dormant tree, injury or tree death can occur if there is
poor agitation which allows the oil and water to separate
and trees receive high concentrations of oil.
Pecan nut casebearer
Although you might think it is a little early to be discussing
PNC, this is a reminder that PNC pheromone traps should
be in the orchard by the first week of April for the southern
part of the state, mid April for central Texas and late
April for the northern area.
The PNC pheromone trap has to be one of the most useful
pest management tools you can use. These traps are inexpensive
and will provide you with important information on the start
of PNC activity. Although these traps can not tell you if
you have to treat or not this trap will tell you when egg
lay starts and when nut entry starts. From many years of
trap monitoring I am confident that egg lay starts between
7 to 10 days after your first initial catch with nut entry
starting 12 to 16 days after this initial catch.
PNC traps have been around for awhile now and should be
available at most dealerships that cater to the pecan industry.
Traps can be purchased as “kits” with kits containing
from 1 to 3 traps plus extra lures and trap bottoms. Remember
that any lure not being used should be stored in the freezer.
We recommend 3 to 5 traps be used for orchards of 50 acres
or less and at least 5 traps for orchards larger than 50
I always recommend that producers purchase at least twice
what they might need. For example if you have a 25 acre orchard
and want to use 3 traps, order at least 6. If one of our
Spring storms blows you traps into t he next county or into
the river, you have extras on hand and will not lose valuable
monitoring time by having to wait for another order.
Additional information on PNC and the use of the pheromone
traps can be found in our Extension publication. You can
access this publication through the Texas A&M Entomology
Anyone needing help in locating a source for PNC pheromone
traps please give me a call.
May 6, 2004
Georgia Pecan Growers Annual Conference
Contact: Jane Crocker, 229-372-5416
June 11-13, 2004
Oklahoma Pecan Growers Annual Conference
Contact: OPGAShelton @aol.com
June 16-18, 2004
Louisiana Pecan Growers Annual Conference
Baton Rouge, LA
Contact: Frances Knox 318-747-3003 or
July 11-14, 2004
83rd Annual Texas Pecan Growers Conference and trade Show
San Antonio, TX
Contact: TPGA - 979-846-3285
Texas County Meetings:
March 30, 2004
Central Texas Pecan Meeting
April 3, 2004
Contact Dirk Arron 254-933-5305
April 7, 2004
Eastland county Field Day and Grafting Clinic
Cisco Jr. College, Cisco, TX
Contact Bob Bailey 254-629-1093
April 20, 2004
Guadalupe County field Day
Contact: Travis Franke 830-379-1972
May 3, 2004
San Saba County Field Day
Contact: Neal Alexander 325-372-5416