An apple scab ascospore maturity model developed in New York [NY] did not satisfactorily predict maturity of V. inaequalis ascospores during 4 seasons in North Carolina [NC]. The model predicted mature ascospores in the winter much earlier than they occurred in nature. The failure of the model under N.C. conditions, apparently was due to certain aspects of the biology of V. inaequalis that were not accounted for by the model and were not noticed because of the environmental conditions in the Geneva, NY, area.