Insect Update

PECAN WEEVIL TRAPS

There are several types of traps for monitoring Pecan Weevil emergence, here we present how to construct three of these traps:

1- CONE TRAPS
2- PYRAMID TRAPS (Tedder's Trap)
3- CIRCLE TRAPS


Some of these traps also can be purchased from these stores (follow link). (Wire Cone, Tedder's trap, Circle trap)




1. CONE TRAP (Adapted from TCE Fact Sheet L-1808)



Cone Traps

Position these traps under pecan trees to detect adult emergence and check every week from mid-July until the end of October. By comparing weekly trap catches, weevil abundance can be assessed accurately. The cone emergence trap method is recommended most often for detecting adult pecan weevils.

A sturdy material for constructing cone traps is 1/8 inch mesh wire hardware cloth. Cut the wire in a 3- foot by 6-foot strip and then fold this strip into a circle (Figure 1). Bring the straight edges together and solder, forming the cone (Figure 2). Leave a 1/4-inch hole in the top of the cone. Place a fruit jar lid rim over the hole and secure it with silicone rubber caulking compound. Be sure enough of the cone is through the ring to form a baffle, so when a jar is attached and weevils are inside, they cannot escape (Figure 3).

Cone Traps


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2. PYRAMID TRAP/Tedder's TRAP (Adapted from OSU Fact Sheet F-7190)


Tedder's Traps
The pyramid trap can be easily constructed from plywood, particle board, or masonite. The thicker grade material (½ inch or more) will last longer depending on use and exposure to weather. A schematic for construction of four of these traps using one 48-inch x 96-inch x 1/2-inch sheet of plywood is provided in Figure 9. Markings on the schematic depict where saw cuts should be made. To insure correct measurements of cuts and minimal waste of materials, measure from left to right along the 96-inch sides as indicated. The two end pieces can be spliced together from the bottom or top side of glueing a 3-inch x 24-inch strip of plywood to each pieced to hold them together.

A 24-inch split is cut in the bottom (center) of half of the pieces. These splits will provide a means of joining the two halves together to form the final product (Figure below ). Two 1/2-inch holes can be drilled in the bottom of one piece of each trap to accommodate tent stakes, gutter nails, or reinforcement rod to anchor the traps in place. For added security, trap panels can be hinged together using 90 angle iron. Once they are assembled, all traps should be painted using a flat, dark brown, or black, 100 percent acrylic latex housepaint. Do not dilute the paint, so that its water-resistant qualities are retained, and traps will not warp. Once the traps have dried, place a modified boll weevil trap assembly on top of the pyramid. The trap top assembly can be secured in place by lightly tapping on the top. Over time, this method of securing the trap top will stretch or break the boll weevil trap assembly; therefore, plastic edging channel can be glued to the inside of the top assembly to accommodate the edge of the paneling. Because the boll weevil is a much smaller insect than the pecan weevil, the entrance hole in the wire mesh should be enlarged to 1/4 or 5/16 of an inch in diameter. When this trap is used for plum curculio, the diameter of the weevil entrance hole should not be changed.

Traps should be placed eight to 10 feet from the trunk of pecan trees and adjacent to the trunk on fruit trees. For small pecan trees, place the trap closer to the trunks, generally under the canopy. When trapping under larger pecan trees, place the trap on the north, west or northwest side of the tree. To further enhance capture using these traps closely mow or treat with herbicide to control grass and other weeds under the tree and around the trap. Trap operation under pecan trees should begin around July 15 and for fruit trees, when blooms begin appearing (about March 15).


To enhance capture within traps and increase repellence on the tree, trunks can be whitewashed with a solution of hydrated lime, salt, and water. Dissolve one pound of salt in two gallons of water. Add the solution to 10 pounds of hydrated lime, and mix well in a five-gallon container. A heavy-duty paint mixer will help with this chore. Screen the mixture through a 20-mesh sieve or standard wire window screen, and stir well before using. This recipe will make 2-1/2 gallons of sprayable whitewash. Large pecan trees may require 1 to 1-1/2 gallons of whitewash to cover the tree trunk. A thicker solution can be prepared for brushing onto the trunk by using only 1-1/2 gallons of water, or white latex paint diluted with 30 to 50 percent water will also work. Painting or whitewashing the tree trunk greatly increases the reflectancy of that surface, thereby decreasing its attractancy for weevils.

The minimum number of pyramid traps suggested per 100 acres of trees is 15; however, in smaller orchards or urban environments, as many early maturing indicator trees should be used as possible. One trap per tree is sufficient to help ascertain weevil emergence period and general population levels. Operation of this trap type should continue throughout the growing season on both fruit and pecan trees. The traps should be inspected and trap tops cleaned out every two or three days.

Tedder's Traps

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3. CIRCLE TRAP (Adapted from OSU Fact Sheet F-7190)

Circle Traps

 

 

 

 

 

 

 

 

 

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Pictures Courtesy Oklahoma State University

Because wire cone emergence traps and pyramid traps on the orchard floor are obstacles to mowing and grazing and because they easily can be damaged by livestock and mowing equipment, alternative designs are being explored by extension personnel in Oklahoma and Kansas. In 1996, extensive evaluations began on a new trap design developed by a Kansas pecan grower, Edmund Circle.

The Circle trap consists of a wire screen cage with a boll weevil trap top and is attached directly to the tree. Therefore, the visual cue of the tree is exploited and nothing clutters the orchard floor. Since tree size varies greatly, trap size and design must be modified.

Material used for this trap consists of aluminum insect screen ing 32-inch x 24-inch mesh. Large rolls 36 inches by 100 linear feet are readily available. Two wood lath pieces, 1 1/2 inches wide x 17 3/4 inches long, and 1 1/2 inches wide x 11 1/2 inches long are needed. The longer (32-inch) edge of the screening is folded into a cone shape, slightly overlapped, and stapled to the shorter piece of wood lath (Figure 1), approximately one inch from the bottom of the seam and top of the wood lath.

Excess screening is cut away at the cone top to ac- com mo date the trap top assembly (Figure 2 and 3). The top assembly is placed between the screening and the wood lath and stapled into place (Figure 4). The longer piece of wood lath is also stapled to the screening and top assembly directly opposite the fi rst piece of wood (Figure 5). A 32- inch piece of nine- to 10-gauge steel wire is stapled into a fold created on the shorter side (outside) of the trap using number 13 book bind ing staples (Figure 6). The wire serves to hold the outside part of the trap open, away from the ree, so that weevils may enter easily.

Finally, the trap top assembly is sealed to the screening and wood lath using hot glue (Figure 7). Remember, for pecan weevils the entrance hole at the top of the cone should be enlarged to 1/4 to 5/16 of an inch. The trap is attached to the tree using two, 1 5/8-inch drywall screws and the bottom of the screening is stapled or strapped to the tree.

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TRAPS ALSO CAN BE ORDERED FROM

Gempler's
P.O. Box 270
100 Countryside Drive
Belleville, WI 53508
Order by Phone: 1-800-382-8473
Order by Fax: 1-800-551-1128

Great Lakes IPM Inc.
10220 Church Road
Vestaburg, MI 48891-9746
Ph: 989-268-5693 or 989-268-5911
Toll Free:  1-800-235-0285
Fax: 989-268-5693
E-mail: glipm@nethawk.com

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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
Department of Entomology at Texas A&M University
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Texas A&M University
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