Strawberries are one of the most valuable crops in Florida. The state produces around 16 million flats of strawberries every year, which represents 15% of nation's berries and virtually all the berries grown during the winter. In 2004, 7000 acres were devoted to strawberries with an estimated return to the grower approaching to $200 million. The high value of the crop often compels growers to protect their profits by making numerous applications of fungicides on a strict calendar schedule. Disease models for timing fungicide applications are being developed and evaluated for anthracnose and Botrytis fruit rot and will enable growers to better evaluate the need for fungicide applications. The environmental factors to be utilized in the models include air temperature, rainfall amounts and durations, and daily hours of leaf wetness. Leaf wetness duration (LWD) is one of the most important agro-meteorological parameters influencing plant disease epidemiology. LWD is a difficult variable to measure since there is no observational standard, for either the sensor or for exposure conditions. A Penman-Monteith approach to estimate LWD was compared to the observed LWD during the 2006-2007 growing season. Initial results indicate a good correlation between observed and estimated LWD suggesting that estimated reference LWD can be used as an input to the disease models being developed. A strawberry “crop coefficient” is being developed and is expected to further increase the agreement between observed and estimated LWD.