This trial evaluated coffee (Coffea arabica) leaf rust control based on rust severity values (RSV) according to climatic variables such as leaf wetness and air temperature during leaf wetness period. Two coffee growing areas were chosen, both in the state of Minas Gerais: a six-year-old coffe plantation in Coimbra in the Zona da Mata at 680 m of altitude, and a nine-year-old coffee plantation in Carmo do Paranaíba in the Alto Paranaíba at 850 m of altitude. In Coimbra, a potentially high yielding coffee plantation, the treatment based on RSV of 30 was similar to the calendar treatment (two sprays of systemic fungicides). In Carmo do Paranaíba, a potentially medium yielding coffe plantation, the treatment based on RSV of 49 recommended one application of systemic fungicide. The treatment based on the calendar preconized two applications for the systemic and four applications of the protective fungicide. In conclusion, the system based on RSV was as good as the calendar treatment for high berry yield coffee plants; for the medium berry yield coffee plants the system reduced at least one fungicide application.
