A prototype of the clear delta codling moth trap developed in 2008 by USDA’s Dr. Alan Knight.
A research report from Alan Knight, USDA–Wapato; Loys Hawkins and Kathleen McNamara, Bear Creek Orchards, Oregon; and
Rick Hilton, Oregon State University
Today, growers have a number of tools to effectively manage codling moth, including sex pheromones, granulovirus, three classes of insect growth regulators, and eight classes of synthetic insecticides attacking different aspects of the insect’s nervous system. Yet, growers must remain concerned about three aspects of codling moth management: the efficacy of integrated programs, continued selection for insecticide resistance, and rising costs of new technology. Underpinning these concerns throughout each growing season is how best to obtain accurate knowledge of whether and when additional tactics should be applied.
New trap designs for monitoring codling moth have also undergone some recent rapid evolution. First, white plastic delta traps replaced the standard wing-shaped cardboard trap. Next, studies showed that an orange delta outperformed the white delta trap for codling moth and avoided the catch of nontargets, such as honeybees. The adoption of the orange delta baited with the combo lure has significantly improved growers’ ability to monitor codling moth in sex-pheromone–treated orchards more precisely.
This approach was tested in 2008 in two Comice pear orchards situated near Medford, Oregon, in a 51-acre conventional and a 17-acre organic orchard. Both were treated with a grid of Checkmate CM puffers at a density of one per acre. The density of orange delta traps baited with the combo lure was more than doubled from 2007 (see "Codling moth trap comparisons"). All spray decisions were made by the grower using action thresholds of one or more females and four or more moths per trap. Most sprays applied during the season were triggered by the catch of a single female moth in a trap; however, male catch did trigger a few sprays. No fruit injury occurred in either orchard. Portions of each orchard were not sprayed with insecticides for codling moth under this program, and this likely increases the opportunities for biological control agents to maintain a range of secondary pest species below economic injury levels. Monitoring costs were higher with the precision program in both orchards due to the increase in traps, but labor and spray costs were considerably lower (see "Orchard costs"). Total costs in each orchard were about 60 percent less using this precision management approach compared to the costs that would have been incurred if the grower’s standard monitoring and spray protocol had been used.
Adoption of the clear delta trap baited with pear ester and acetic acid has the potential to improve a grower’s capacity to gauge risk and apply supplemental insecticides more judiciously. This new lure-trap combination may solve two of the major limitations of our past monitoring systems for codling moth: effectively catch females without the need to identify the sex of moths and catch a similar number of moths as our best pheromone lure so that existing thresholds may not have to be changed. Growers will vary on how they choose to use this new trap-lure system. Likely, several years of field use will be needed to gain sufficient practical experience to establish new action thresholds and to recommend a standardized protocol for trap density and placement in orchards.