Forecasting emergence, flight, and oviposition of Spilonota ocellana (Lepidoptera: Tortricidae), in British Columbia

Eyespotted bud moth, Spilonota ocellana (Denis & Schiffermuller), is becoming an important pest of pome fruits in British Columbia because implementation of noninsecticidal controls for codling moth, Cydia pomonella L., have removed routine sprays that inadvertently controlled it. Knowing the phenology of S. ocellana could improve timing of controls for this pest. Seasonal flight activity of male, eyespotted bud moths was monitored using pheromone-baited traps hung in unsprayed apple (Malus pumila Mill.) orchards in the Okanagan Valley of British Columbia from 1993 to 1996. Emergence of adult males and females and oviposition was monitored from 1994 to 1996 to establish relationships between their phenology and accumulated degree-days above 10 degrees C air temperature or number of days after the 1st moth was caught (biofix). Biofix occurred between 1-5 June, except in 1996, when it occurred 2-3 wk later, and flight activity continued until late August. Males and females emerged on the same day, 2.0 +/- 1.7 d (mean +/- SD, n = 3 yr) before biofix, and oviposition began 4.3 +/- 1.5 d after biofix. The nonlinear relationship between cumulative trap catch and d or number of degree-days after biofix was modeled with cumulative Weibull functions. A model based on data from Summerland using days after biofix as the predictor variable was more accurate at predicting the interval between biofix and 50% cumulative trap catch for independent data sets from Kelowna and Winfield than a model using degree-days after biofix as the predictor variable. However, the use of degree-days as a predictor variable has wider application to other regions and years. Similar models were used to describe the relationship between days or degree-days after biofix and cumulative emergence of males, emergence of females, and oviposition, respectively. These models will assist in the development of pheromone-based management programs for the eyespotted bud moth, and can be used to formulate control strategies for this pest.