A COMPARISON OF TWO TEMPERATURE-DEPENDENT DEVELOPMENT MODELS FOR IMMATURE STAGES OF THE NANTUCKET PINE TIP MOTH (LEPIDOPTERA: TORTRICIDAE)

Parameters for a degree-day model (DD) and the Sharpe-DeMichele poikilothermic model (POIK) were estimated for the development of Rhyacionia frustrana (Comstock) immature stages. A comparison of the accuracy between the two models was made for eggs, larvae, and pupae. The DD and POIK model were equally effective for predicting development of eggs, but the POIK model was superior for predicting larval and pupal development. Regression analysis of predicted vs. observed development days show a good fit (R2 > 0.99) for eggs using both models, a relative good fit (R2 > 0.90) for larvae and a poor fit (R2 < 0.85) for pupae. Threshold temperatures were at 10.0°C for eggs, 7.0°C for larvae, and 9.8°C for pupae. Optimum hatch was 100% for eggs at 24°C and required 81 DD; optimum survival was 77% for larvae at 21°C and required 704 DD; and optimum eclosion from pupae was 55% at 26°C and required 227 DD.