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Trapping
Trapping is the first line of attack in boll weevil eradication operations. Trapping identifies the location of boll weevil populations and measures their densities.
Trap Description
The boll weevil trap has three parts: a body, a molded screen cone and a collection chamber. The yellow-
green trap body mimics the plants the boll weevil lives in and feeds on.
An artificial pheromone contained in a polyvinyl-chloride dispenser is placed in the collection chamber to attract weevils along with an insecticide strip to kill weevils that enter the trap.
Weevils attracted to the trap land on the outside of the body and crawl to the inside of the cone. An opening in the top of the cone allows the weevils to enter the collection chamber.
Trapping Density
Traps are placed around fields at the rate of one trap every tenth of a mile. However, the density may be doubled to two traps per one-tenth of a mile alongside any overwintering habitat areas such as brush, grass, shrubs, weeds, etc. In the latter stages of a program, trap density is reduced.
Traps between two adjacent cotton fields are spaced at one trap per one-tenth of a mile by alternating trap positions and assignments between the two fields.
Trap Placement
Traps are placed around the perimeter of all cotton fields on a four-foot long, wooden stake driven into the ground. Each trap is set on a nail halfway driven into the top of the stake to hold the trap upright in high winds or other disturbances.
Traps are placed as near to the cotton field as possible but in a position that avoids the regular path of field equipment or other traffic. This keeps the traps from being damaged and maintains a high level of trap effectiveness.
Also, the trap is positioned in as open an area as possible, free from weeds, brush or other obstacles that may obstruct trap visibility or interfere with free airflow to and from the traps.
The work unit number, field number and trap number are marked on the outside of the trap body. Each trap is identified with a unique number to precisely pinpoint the location of each trap capture. Trap numbering begins with No. 1 at the northeast corner of each field, moving counterclockwise around the field with subsequent trap numbers 2, 3, 4 etc.
Note: The traps used in the eradication program are important to the program’s success. Cotton producers are asked to take care when working around the traps to ensure the traps are not damaged or destroyed. Growers are encouraged to work with their field unit supervisors.
Trap Inspection
Traps are inspected once a week.
The lure is replaced every two weeks. The date of lure replacement is indicated on the lure by marking the date on the lure with a permanent marker pen.
Insecticide strips are replaced once a month. Insecticide strip replacement is indicated by marking “I.S.” next to the trap-servicing date on the trap body.
Trappers also check the current crop stage in the field next to each trap and report the most advanced stage.
Bar-Code System
The bar-code system is a crucial part of the boll weevil trapping program. The bar code for each trap is unique, associating the data from a particular trap to a computerized map location.
Each time a trap is inspected a hand-held scanner is used to read the bar code. The time and date of inspection as well as the sequence in which the traps are serviced are automatically recorded.
Trappers also record crop stage, number of weevils found in the trap, replacement of pheromone and insecticide dispensers and trap condition.
Quality Control
Quality control ensures program guidelines for boll weevil trapping are being properly implemented and is conducted throughout the season. A minimum of 15 percent of all fields in each work unit are randomly selected on a weekly basis. Quality control consists of:
Visual Inspection -- A supervisor inspects ttraps and reports on whether the traps have been properly mapped, placed at the correct density and properly positioned. The inspecting supervisor also checks to be sure the lure and insecticide strips have been properly replaced and whether the proper information has been recorded on the trap body.
Spiking -- The inspecting supervisor will plant a known number of weevils or tokens in a percentage of the fields selected for quality control that week.
Information gathered by the supervisor is entered into the computer and subsequently compared with the relevant daily trapping report when it is submitted. This comparison verifies that the spiked weevils were recovered and allows Foundation personnel to determine how many weevils were actually captured in the trap.
Trappers who fail to retrieve spiked weevils or tokens or report false data are subject to disciplinary action, including termination.
