(UF/IFAS) — Just one freeze could cripple much of Florida’s citrus crop. It happened 30 years ago. Chris Oswalt, a multi-county commercial citrus agent for University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Extension, remembers the frost-bitten evenings. Christmas 1983, January 1985 and Christmas 1989 marked three of the worst citrus freezes in the state’s history. Even though …