Texas Cooperative Extension

Texas Cooperative Extension
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September 20, 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.

This will be the last scheduled newsletter of 2004.  I'll start again next March.

Harvest has started in south Texas on the Pawnees with yields being a little light. There have been scattered showers across the central portion of the state but nothing that will interfere with harvest. Third generation PNC has been heavy in some orchards and could impact quality.

Black Pecan Aphid: Leaflets damaged by black pecan aphids will have rectangular necrotic (brown or yellow) areas between the leaf veins. Damaged leaves will continue to drop up to first frost.

Hickory shuckworm: Damage from hickory shuckworm will become apparent at harvest. HSW larvae will be a creamy dirty white color while PNC larvae are dark. It is too late to do anything now for this years crop. If infestations are heavy - make plans for next year!

Pecan nut casebearer: Third generation PNC has been heavy in many orchards during August and September. During this time of year you can separate PNC activity from hickory shuckworm by the frass that is pushed outside the nut at the base of the cluster by PNC larvae (see picture). The black granular frass is from PNC. Hickory shuckworm larvae do not push the frass outside the nut. Third generation PNC is hard to scout for the pecans are large and eggs can be laid any where on the nut. Often times they (eggs) are at the base of clusters where the pecans are touching.

Pecan weevil: For those producers with adult emergence traps, continue to monitor traps up to harvest. If the soil in the orchard becomes hard due to drought there could be a delayed adult emergence and pecan weevil can feed on pecan up to shuck split. A pecan weevil management program will require at least two applications.. I feel that producers should take notes on their pecan weevil management program, notes on percent damage, yields, location of infestations., insecticides used, irrigation or rain fall dates - and amounts will help one evaluate his/her program.
One number to remember is that it is approximately 42 days from egg lay to grub emergence. If grubs are observed emerging from pecans look back 6 weeks to see what happened at that time which allowed females to lay eggs in nuts.

Stink bugs/Leaffooted bugs: During the late summer and early fall is the time of year when adult stink bugs, primarily the southern green, green, brown and dusky stink bugs and leaffooted bugs can move into orchards from other host plants. Unfortunately there are no defined treatment thresholds for this group and most effective insecticides can not be applied within 21 to 28 days of harvest or after shuck split. With the difficulty in scouting and the possibility of late season damage (can feed on pecans during harvest) this presents a challenge to both producers and researchers alike.

If anyone has tried using a trap crop to manage stink bugs I would like to hear about the results - good or bad.

I am also trying to gather information on the impact of stink bugs/leaffooted bugs on the crop and what they are costing producers. Please complete the short survey at http://pecankernel.tamu.edu/surveys/stinkbugsurvey.htm, or you could fill out or answer the following.

1. State

2. County(ies) where orchard(s) are located

3. Type of production
a. commercial # acres improved
b. native # acres

4. Varieties with damage

5. Do you recognize stink bugs? Yes No
(online survey has color pictures)

6. How do you sell your pecans? Check all that apply.

a. wholesale only
b. wholesale and retail
c. retail inshell only
d. retail cracked
e. shelled

7. Do you grade your pecans prior to sale?
Yes No
if yes - estimated dollar loss
or estimated percent kernel damage

8. Did you apply an insecticide for stink bugs?

Yes No

If yes how many acres? ___________

Cost of treatment $_____________

month of treatment. _____________

9. Other comments ________________________

Your name is not required and all individual information will be confidential.

Walnut caterpillar: I received one report from an east Texas forester this week that he had observed a lot of walnut caterpillar activity in east Texas recently. Now this may be old news to some of you but I don’t see much of east Texas so I’m passing the information along.

In Texas there can be either two or three generations per year depending on the number of frost free days with the three generations occurring in the southern and eastern portions of the state.

Walnut caterpillar larvae feed in colonies and do not construct any type of webbing. Female moths deposit egg masses which can contain over 600 eggs on the underside of leaflets and larvae will go through 5 instars with most of the damage occurring during the 5th or last instar.

Young larvae feed only on soft tissue, leaving a skeletonized leaf while older larvae feed on the entire leaf. When it is time to molt the colony will move as a group to the main trunk or a scaffold limb and leave behind a clump of cast skins.

Natural control is achieved through various egg and larval parasites and numerous predators. However, if an insecticide is needed, there are numerous products which can be used. If livestock are grazing in the area to be treated then grazing restrictions will have to be observed.

Colony of walnut caterpillars

Texas Counties
September 22, 2004
Guadalupe county
Contact: Travis Franke 830-379-1972

September 23, 2004
Galveston county
Contact: William Johnson 281-534-3413

October 5, 2004
Bell county
Contact: Dirk Arron 254-933-5305

November 16, 2004
Fort Bend county
Contact: Sarah Lineberger CEA-Hort

State Meetings
September 25-26, 2004
18th Annual Mississippi Pecan Festival
Richton, MS
Contact: 601-525-3792

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.

Department of Entomology at Texas A&M University
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