Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/17/2014
Publication Date: 11/1/2016
Citation: Jones, V., Horton, D.R., Mills, N., Unruh, T.R., Miliczky, E., Shearer, P., Baker, C., Melton, T. 2016. Using plant volatile traps to develop phenology models for natural enemies: an example using Chrysopa nigricornis (Burmeister) (Neuroptera: Chrysopidae). Biological Control. 102:77-84. Interpretive Summary: Efforts to incorporate biological control of insect pests in orchards are complicated by difficulties in predicting when during the spring and early summer natural enemies are likely to arrive in orchards. Scientists with Washington State University, USDA-ARS, University of California, and Oregon State University used an attractant trap to monitor populations of a lacewing beneficial insect in orchards, and used these observations to develop a seasonal predictive model of occurrence. The model was found to accurately predict spring arrival and population peaks of the lacewing in orchards of Washington, Oregon, and California. These results will assist growers in knowing when beneficial insects are likely to be present in their orchards, helping growers more effectively time other pest control measures
Technical Abstract: A model predicting phenology of adult Chrysopa nigricornis (Burmeister) (Neuroptera: Chrysopidae) in orchards was developed from field (trapping) data supplemented with developmental data collected under laboratory conditions. Lower and upper thresholds of 10.1°C and 29.9 °C, respectively, were estimated from published and unpublished laboratory trials, and were used to process the field data. Season-long field data were collected using white delta traps that had been baited with a volatile compound (squalene) shown elsewhere to be highly attractive to C. nigricornis. The model was developed from data collected in three Washington apple orchards, and then was evaluated for error rates in independent data sets collected from apple, sweet cherry, pear, and walnut orchards across a much wider geographic region. We found that the mean absolute deviation across all crops and years was 39.7 ± 1.2 day-degrees, or 4.4 ± 0.14 days. Populations of C. nigricornis in walnut orchards of California emerged 105 DD later than those in Oregon and Washington, thus requiring the subtraction of average time of first catch (105 DD) to synchronize models. The ability to use a single model across multiple crops, different prey species and abundances, and different pesticide regimes demonstrates that natural enemy models may have a broader applicability than in the system in which they had been developed. These models also suggested that prey phenology was not a critical factor affecting lacewing phenology.