Nantucket Pine Tip Moth Phenology and Timing of Insecticide Spray Applications in the Western Gulf Region
The Nantucket pine tip moth, Rhyacionia frustrana (Comstock) (Lepidoptera: Tortricidae), is a common pest of pine plantations throughout the Southern United States. The objectives of this study were to predict the phenology of R. frustrana populations throughout the Western Gulf region, and to provide optimal spray periods for locations that have three or four generations annually. The thermal requirements necessary to complete a generation were obtained from published data, and used in conjuction with historical temperature data to model phenology throughout the region. Four generations were predicted to occur annually throughout many of the pine producing regions of Louisiana, northeastern Texas, and southern Arkansas. Three generations were predicted for the Ozark and Ouachita Mountain ranges in Arkansas. Five generations were predicted for extreme southern portions of Louisiana and throughout southeastern Texas. Spray timing prediction values were also obtained from published data and used to predict optimal spray periods based on 5-day increments for each location where either three or four generations occurred. Tables containing the predicted optimal spray dates are provided for numerous locations within each state. Validations were conducted in Lousiana and east Texas to determine the effectiveness of this technique to achieve adequate spray timing. There was 57 percent agreement between the optimal spray periods and field-determined spray dates based on insecticide efficacy studies. Land managers who use contact insecticides, such as pyrethroids, can use these data for optimizing spray effectiveness within the Western Gulf region.
This paper serves as a companion to a previously published work for the Southeastern United States (Fettig and others 2000a), and thus completes phenology and optimal spray period descriptions for R. frustrana throughout the Southern United States.