Day-degree models for predicting the generation time and flight activity of local populations of Lobesia botrana (Den. & Schiff.) (Lep., Tortricidae) in Greece

The generation time of Lobesia botrana (Den. & Schiff.) was estimated as the number of day-degrees required between the start of a flight and the start of the following flight in two regions in northern Greece. The day-degrees required for the first generation (x = 339.3, Naoussa; x = 275.6, Thessaloniki) were significantly shorter than for the second (x = 751.5. Naoussa, x = 833.8. Thessaloniki) and the third generations (x = 899.5, Naoussa, x = 1197.0, Thessaloniki). Nonlinear models were developed using trap catches of male L. botrana during 1987-1989 for predicting its flight activity. A lower threshold temperature of 6.45degreesC was used in calculating daily day-degrees from 1 March. The models predicted with sufficient accuracy the accumulated male moth catch and they accounted for the 60-78%. and 86-91% of year-to-year variation in male flight activity in Thessaloniki and Naoussa, respectively.