Submitted to: Journal of British Columbia Entomological Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/20/2004
Publication Date: 12/20/2004
Citation: Knight, A.L., Light, D.M. 2004. Stimulation of oviposition by codling moth (Lepidoptera: Tortricidae) exposed to ethyl (E,Z)-2,4-decadienoate. Journal of British Columbia Entomological Society. 101:53-60. Interpretive Summary: Improved methods to monitor egg laying by codling moth would improve management of this important pest. Researchers at the USDA - ARS Yakima Agricultural Research Laboratory found that a chemical from ripe pear odor, pear ester, stimulated egg deposition by codling moth in a series of laboratory experiments. Enhancement of egg deposition was noted for both a laboratory and a field-collected strain. Field trials, however, were not successful in stimulating egg lay on non-fruiting shoots in apple or near fruit clusters in apple or nut clusters in walnuts. Further testing is needed to develop an effective monitoring trap for egg deposition by codling moth.
Technical Abstract: The effect of the pear volatile, ethyl (2E, 4Z)-2,4-decadienoate (Et-E,Z-DD), on oviposition by codling moth, Cydia pomonella (L.), was evaluated in a series of choice and no-choice laboratory experiments and in subsequent field tests conducted in apple and walnut. Gray halo-butyl elastomer septa loaded with 1.0 ' 100.0 'g Et-E,Z-DD significantly increased the numbers of eggs laid by a laboratory population in 96 h no-choice assays by 2- to 4-fold. In addition, the number of eggs laid near the Et-E,Z-DD versus a solvent blank dispenser was significantly higher in choice bioassays across a similar range of septa loadings. Oviposition rates by a field-collected post-diapause strain of codling moth were significantly increased by the addition of 1.0 'g septa in a no-choice bioassay. Preliminary field trials were conducted in apple and walnut to develop an artificial egg trap baited with Et-E,Z-DD to monitor codling moth oviposition. Septa loaded with 0.1 to 10.0 mg did not significantly increase oviposition versus blank septa on a Mylar plastic collar trap or on the adjacent leaves and fruit in apple. Significantly more eggs were laid on the fruit and foliage than on the plastic collar. No eggs were deposited on non-bearing apple shoots baited with 0.1 ' 40.0 mg Et-E,Z-DD septa. Similarly, no eggs were deposited on cylindrical plastic traps baited with 10.0 'g to 1.0 mg Et-E,Z-DD septa in walnut orchards. The potential role of Et-E,Z-DD to monitor egg laying by codling moth under field conditions is discussed.