1a.Objectives (from AD-416):
1. Evaluate the correlation of leafroller adult catches in traps baited with pear ester and acetic acid with local larval populations within orchards.
2. Evaluate the relative attractiveness of other host plant volatiles in combination with acetic acid for both leafrollers and codling moth.
1b.Approach (from AD-416):
Orchards with known leafroller populations will be identified in the Wenatchee and Yakima Valleys. Blocks will be monitored with traps baited with acetic acid and pear ester. Leafroller larval populations and fruit injury will be sampled and correlated with moth catches. Replicated trials will be conducted in a few sites to compare the attractiveness of several different host plant volatiles plus acetic acid.
Monitoring of key pest species is a key element of integrated pest management programs developed for tree fruits. ARS researchers in Wapato, WA have addressed the need to develop more cost-effective means to monitor these pests. Traps baited with a single combinational lure were developed and tested for codling moth and two leafroller species in Washington, Oregon, and Utah. In particular, the effectiveness of this lure in allowing an estimate of the local pest population within orchards was the objective to allow growers to respond to within-orchard pest problems. Studies found that the addition of an acetic acid co-lure to the sex pheromone-pear ester combo lure-baited traps significantly increased codling moth catches. A commercial acetic acid lure, Pherocon AA, was developed for codling moth as a result of this research. The optimal daily release rate of acetic acid from lures required to be effective for both codling moth and leafrollers was found to be between 10 – 50 mg which is much higher than the rate of the Pherocon AA lure, < 5 mg/d. Acetic acid lures can be formulated that are effective for both Pandemis and Oblique banded leafrollers. Five other host plant volatiles in addition to pear ester combined with codling moth’s sex pheromone and used with an acetic acid lure performed similarly in traps for Pandemis leafrollers, and both beta ocimene and nonatriene were as attractive as pear ester for codling moth. The use of the AA lure with the sex pheromone-pear ester combo lure provided useful predictive capabilities to detect either the presence of either leafroller species within the orchard or the threat of nearby leafroller populations invading the orchard. Within orchards isolated from potential leafroller infestations the traps generally did not catch any leafroller adults. The work reported here addresses objective 3 of the parent project plan.