Comparison of different fireblight prediction systems under creek climatic conditions

Firescreens and "Maryblyt" prediction systems of fire blight epidemics were evaluated and compared under greek climatic conditions during 1997 and 1998 growing seasons. In both years the number of sprays recommended by the systems was less than the usually applied ones, on the basis of phenology. In 1997 "Firescreens" recommended 1 or 2 sprays while "Maryblyt" none. In 1998 both systems recommended almost I spray. The results obtained suggest that both systems could be considered reliable since, there were no symptoms in most (15 out Is) experimental orchards and consequently there was no need for the two or three conventional sprays. In the orchards under heavy inoculum pressure, both systems gave less satisfactory control. "Firescreens" usually predict more infection days than "Maryblyt". However the infection days predicted by both systems coinside. Concerning the day of symptoms appearance "Firescreens" predicts it 1-2, days earlier than the actual day while "Maryblyt" 5 days later. The systems need further evaluation under more favourable conditions for fire blight epidemics and havier inoculum pressure.