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Pheromone Design and Placement

Mori material with 99°70 pure Farnum et al.“ (+ trap catches at the range of bait concentration used, with an increasing response with increasing baiting levels of 1 to 100 pg. Plimmer et al.” and Cardé et al." used similar wicks and traps and arrived at identical conclusions. Miller et al."‘ used a system that probably had a higher release rate which accounts for their response data “topping out” at 10 pg. This is similar to the findings of Butt et al.,‘°° who reported that the optimum charge of pheromone for trapping male codling moths was 0.1 to 1.0 mg, depending on the trap type and duration of the test. Similar results were observed with the cabbage looper, Trichoplusia ni (I-Iiibner). ‘°‘

Numerous release systems have been used to dispense pheromones, including dispar- lure. For a discussion of this subject, see Campion et al.“” and Plimmer et al.‘°3 “Keepers”, such as trioctanoin, are sometimes added to retard evaporation of the pheromone, to give desired emission characteristics or to prolong wick life.” Emission rates vary greatly with the type of dispenser, and are also affected by tem- perature, air speed across the dispenser, humidity, amount of pheromone in the dis- penser, and by the chemical properties of the pheromone or pheromone blend. Learn more at

Pheromone Design and Placement

A key component of a mass-trapping strategy is the efficiency of the trap. Numerous

traps have been used in the gypsy moth program including sticky substances painted on trees with female extract in the center.‘ A similar “trap”, a paper strip coated with adhesive with a pheromone source in the center, has been used for gypsy moth work in the U.S.S.R.° The trap used in the studies of Forbush and Fernald" was the Shaw trap."-' a wooden platform with perpendicular wings in the form of a cross with both At the base of the crossed wings was the platform and the wings coated with adhesive. Learn more about pheromones at

The Johnson trap"‘ was a paper “coffee cup" type of trup with very low capacity but quite inexpensive, and was used by Beroza et al.,“ who also described a triangular trap. This latter trap" had adhesive on two sides and was baited with racemic dispar- lure released from a plastic laminate dispenser stapled to the third (uncoated) inner wall. This led directly to the delta trap“"°° which is identical to the triangular trap except that the ends are partially closed to prevent the entrance of birds and small mammals. The delta trap is currently widely used as a survey trap.

All of the above traps are adhesive traps and have limited capacity. A major advance was made by Granett,"5 who introduced a high-capacity box trap with a dichlorvos- impregnated strip to kill male gypsy moths entering the trap over the course of the season. This design was modified by Carde and associates,’’-“ who called the trap a “no exit” trap. Embody"° used a 9.6 I trap containing a dichlorvos-impregnated strip in trapping studies designed to relate male capture data with egg mass density. This trap,‘” termed the Gerberg trap, has an estimated capacity of more than 6000 moths. A similar trap, the “milk carton” trap, is currently being developed by the Animal Plant Health Inspection Service (Figure l).

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