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TEXAS PECAN GROWERS ASSOCIATION
August 26, 2004
Anyone wanting this newsletter by e-mail 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.
Overall I think we still have a pretty good crop. Pecan scab
has been a problem in some areas most of the season due
to all of the rain. Concerns this time of year include
insects - pecan weevil, hickory shuckworm, stink bugs/leaffooted
bugs and black pecan aphids; wildlife management- crows
and squirrels and getting orchard floors ready for harvest.
Black Pecan Aphid: I’ve received one report of black
pecan aphid activity this week. Although BPA can be found
all season it is generally a late season pest. The treatment
threshold for black pecan aphids is when populations reach
an average of 3 per compound leaf (both adults and immatures).
Adults and immatures can be found on both the upper and lower
surfaces of the leaflets and watch for infestations to begin
in the interior portion of the tree. Feeding by both immatures
and adults cause the characteristic yellow rectangular blotches.
Feeding damage will result in early or premature defoliation.
From the literature I have read the worst time for a pecan
to defoliate is during September. This late summer/ fall
time of year is very important in that pecans are trying
to fill out this years set of nuts plus trying to store up
energy for next year. It is important that trees retain their
foliage up to first frost.
Insecticides for BPA include: dimethoate
(Dimethoate E267) @ 1 pint per acre; imidacloprid (Provado
1.6F) @ 7 - 14 oz per acre; chlorpyrifos (Lorsban 4E) @ 2
- 4 pints per acre; pymetrozine (Fulfill) @ 4.0 oz per acre;
thiamethoxam (Centric 40WG) @ 2.5 oz per acre and malathion
.(Malathion 57EC) @ 1-2 pints per 100 gallons.
Pecan weevil: The first insecticide application for pecan
weevil should have gone out by this time. I included a section
on pecan weevil in my last newsletter and will rerun it.
Pecan weevil is a very important insect and it can be managed.
The objective of the pecan weevil management program is
pretty simple - that is, prevent female weevils from ovipositing
in nuts. In order to do this we recommend you do three things:
1) monitor kernel development to know when pecans are susceptible
to oviposition; 2) use some type of adult emergence trap
(wire cone, pyramid, Circle) to monitor adult activity and
3) use carbaryl insecticide.
Adult female pecan weevils are not able to successfully
oviposit in pecans until the kernel is in the late gel stage/early
dough stage. Pecans mature from the tip end towards the stem
end so always check the tip end for the most mature kernel
The first insecticide application should go out around August
20 or when kernel development of the earliest maturing varieties
you want to protect reach the late gel stage. This initial
treatment will go out regardless if you have collected adults
in your traps. A second application should go out 10 days
later if you are collecting adults in traps. Continue to
monitor traps up to harvest. A pecan weevil management program
will take at least 2 treatments but sometimes additional
applications will be needed.
Our recommended insecticides for pecan weevil include carbaryl
(Sevin 80S, Sevin 50WP) and cypermethrin (Fury 1.5ES). Do
not add any binding or sticking agent with your spray. For
pecan weevil control you do not want your insecticide bound
to the foliage. Note: Fury is being fazed out and replaced
with a similar product called Mustang Max. These two products
are almost identical, however, the active ingredient in Fury
is 1.5 lbs AI per gallon and Mustang Max is only 0.8 lbs
AI per gallon and the labeled rates per acre for both products
are almost identical.
Pecan weevil is not distributed across all of Texas and
we are always watching for new infestations and county records.
To date our distribution records of pecan weevil infesting
pecan in Texas include the following counties: Anderson,
Angelina, Archer, Bandera, Baylor, Bell, Blanco, Bosque,
Bowie, Brown, Burnet, Callahan, Camp, Cass, Cherokee, Childress,
Clay, Coke, Coleman, Collin, Comanche, Concho, Cooke, Coryell,
Crockett, Dallas, Dawson, Delta, Denton, Dickens, Duval,
Eastland, Edwards, Ellis, Erath.
Falls, Fannin, Fisher, Foard, Franklin, Freestone, Frio,
Glasscock, Gillespie, Grayson, Gregg, Hall, Hamilton, Hardeman,
Harrison, Haskell, Henderson, Hill, Hood, Hopkins, Howard,
Hunt, Irion, Jack, Jim Hogg, Johnson, Jones, Kaufman, Kendall,
Kent, Kerr, Kimble, King, Knox, Lamar, Lampasas, Leon, Limestone
,Llano, Lubbock, McCulloch, McLennan, Madison, Marion,Martin,
Mason, Menard,Midland Mills, Mitchell, Montague, Montgomery,
Morris, Nacogdoches, Navarro, Nolan, Palo Pinto, Parker,
Polk, Rains, Red River, Regan, Rockwall, Runnels, Rusk.
Sabine, San Augustine, San Saba, Schleicher, Schackelford,
Smith, Somervell, Stephens, Sterling, Stonewall, Sutton,
Tarrant, Taylor, Terry Throckmorton, Titus, Tom Green, Upshur,
Upton ValVerde, Van Zandt, Walker, Webb, Wichita, Wilbarger,
Williamson, Wise, Wood, Young and Zavala.
If you should observe an infestation and your county is
NOT listed please contact me.
In commercial orchards we recommend two insecticide applications
beginning at half shell and a second application 10 to
14 days later. Recommended insecticides include: tebufenizide
(Confirm 2F) @ 8 - 16 oz per acre; chlorpyrifos (Lorsban
4E) @ 2-4 pts per 100 gallons; esfenvalerate (Asans XL)
@ 2.56-4.27 oz per acre; phosmet (Imidan 70WSB) @ 1.5-2.0
lbs per 100 gallons; spinosad (SpinTor 2SC) @ 4 - 10 oz
per acre and methoxyfenozide (Intrepid 2F) @ 4 - 8 oz per
Stink bugs/Leaffooted bugs
This is the time of year when adult stink bugs and leaffooted bugs start leaving
some of their primary host plants and can migrate into pecans. Watch for
adults on clusters on the border rows. There are no treatment thresholds
for managing this complex of true kernel feeding insects. Treatment of border
rows can help reduce infestations without having to treat the entire orchard.
For those producers that planted trap crops watch for adults in these alternate
hosts. Treat the trap crop with an insecticide once the host plants start
Insect of interest: In case you think that the stink bug
/leaffooted bug complex doesn’t have any natural enemies
think again. It is common this time of year to see stink
bugs with parasite eggs attached (see picture). The following
is some information on one of the main parasites of stink
bugs - the feather legged fly.
Feather-legged fly: Trichopoda
pennipes (Diptera: Tachinidae)
is a tachinid parasitoid of members of the stink bug and
leaffooted bug families. It has a wide distribution in both
North and South America.
It occurs throughout much of the United States, and in the
southern states its major hosts are the southern green stink
bug Nezara viridula and leaffooted bug Leptoglossus phyllopus.
It is sometimes referred to as the "feather-legged fly" because
of the prominent fringe of feather-like bristles on its hind
legs. This distinctive and conspicuous fly is bright orange
with a velvety black head and thorax. It has dark legs with
a fringe of short black hairs on the hind leg and yellow
feet, large brown eyes and brown and black wings. The tip
of the female fly's abdomen is black. T.
pennipes is highly
attracted by an aggregation pheromone produced by male southern
green stink bugs, which results in the males being parasitized
at a consistently higher level than females. Each female
fly lays on average 100 eggs, which are placed singly on
the body of a large nymph or adult bug. Most of the small,
white or gray, oval eggs are placed on the underside of the
thorax or abdomen, but they can occur on almost any part
of the bug. Many eggs may be laid on the same host, but only
one larva will survive in each bug. The young larva that
hatches from the egg bores directly into the host body. The
maggot feeds on the body fluids of the host for about two
weeks, during which time it increases to a size almost equal
to that of the body cavity of its host. When it has completed
its development, the cream-colored third instar maggot emerges
from the bug between the posterior abdominal segments. The
bug dies after emergence of the fly, not from the parasitoid
feeding, but from the mechanical injury to its body. The
maggot pupates about an inch down in the soil in a dark reddish-brown
puparium formed from the last larval skin, and an adult fly
emerges about two weeks later. There can be three generations
per year depending on location.
The fly overwinters as a second instar larva within the
body of the overwintering host bug. Adult flies emerge
in late spring or early summer. The only bugs large enough
to parasitize at this time are overwintered adults. Subsequent
generations develop on both nymphs and adults of the
Adult flies feed on nectar, especially from plants such
as wild carrot (Queen Anne's lace) and meadowsweet, Spiraea
salicifolia. The rate of parasitism can be as high as 93%
on southern green stink bug and up to 80% on squash bug.
But because the bugs continue to feed after parasitization,
T. pennipes will not always prevent crop damage. However,
the reproductive organs of the host bug begin to atrophy
when the parasitoid reaches the second instar, so pest
population increase will be reduced somewhat. The fly is
most effective when it parasitizes nymphs, since 50% die
before becoming adults and the remainder that become adults
and overwinter will die before laying eggs.
(Information on the Feather legged Fly was from Susan Mahr,
University of Wisconson - Madison)
Southern green stink bug with T.
Photo by Juan Lopez - USDA, APHIS, College Station TX
Fort Bend county
November 16, 2004
Contact: Sarah Lineberger CEA-Hort
September 15-16, 2004
Alabama Pecan Growers
Contact: Monte Nesbitt, firstname.lastname@example.org
September 17, 2004
Arizona Pecan Growers
Palo Verde Holiday Inn, Tucson, AZ
Contact: Mike Kilby, Phone: 520-403-4613 or email email@example.com