Submitted to: Good Fruit Grower
Publication Type: Popular Publication
Publication Acceptance Date: April 1, 2007
Publication Date: May 1, 2007
Citation: Knight, A.L. 2007. Codling Moth has a New Calendar. Good Fruit Grower 58(5):16-17. Interpretive Summary: Predictive models developed nearly 30 years ago are still widely used to forecast when insecticides should be applied to target the most susceptible life stages of codling moth which is the key pest of apple and pear. Studies conducted by researchers at the Yakima Agricultural Research Laboratory examined the seasonal pattern of adult activity and egg hatch over four years to see if the model is still correct. Analysis of these data found that the model does not correctly predict the period of egg hatch during the first generation of codling moth. This error likely impacts the effectiveness of current spray programs for codling moth.
Technical Abstract: Studies were conducted in 10 apple orchards in Washington State from 2003-2006 to characterize the seasonal cumulative curves of codling moth flight and the occurrence of fruit injury. Data from each generation were fit to logistic curves and these data were compared to a current widely-used model. The only significant difference found was for the cumulative curve of egg hatch during the first moth generation. Data from the four-year study found that the peak in egg hatch occurred much later than previously predicted. The importance of knowing the correct shape of the cumulative curve of egg hatch is emphasized by comparing several hypothetical pest management scenarios using either the old or new model. Several modifications in the current pest control program for codling moth are suggested.