Good quality apples are grown in relatively cold areas. However, frost frequently causes damage to flowers and small fruits. When the percentage of frost damage losses is higher than the
thinning requirement of the cultivar, production is reduced. In addition to reducing yield, frost damage to the skin and malformation of the fruits often devalues the quality and reduces
profits.
Critical temperature tables in relation to phenological stage are available for apples and other deciduous crops (Ballard and Proebsting, 1978; Proebsting and Mills, 1978). Some of the
data came from field observations using temperatures from standard shelters and some came from excised branch chamber studies. Since plants adapt to the short term temperature
environment and there are biological and physical phenomena that influence the critical damage temperature, extrapolation of these critical temperatures to a given crop and environment
is questionable. For a thorough discussion see Snyder et al. (2004).
In this paper, a program that predicts the fraction of damage to flowers and fruits, and hence the reduction of high quality production, is presented and validated using minimum
temperature data and the observed fraction of damaged apple flowers of three cultivars from 13 locations over two years of multiple frost events
