Nachmias, A., Gilat Regional Experiment Station, Mobile Post, Negev, 85280, Israel
Caligari, P.D.S., Scottish Crop Research Institute, Pentlandfield, Roslin, EH25 9RF, Midlothian, United Kingdom
Mackay, G.R., Scottish Crop Research Institute, Pentlandfield, Roslin, EH25 9RF, Midlothian, United Kingdom
Livescu, L., Gilat Regional Experiment Station, Mobile Post, Negev, 85280, Israel

The effects of two major fungal diseases of potatoes growing in hot climates, early blight (Alternaria solani) and Verticillium wilt (Verticillium dahliae), were investigated in field trials. Large populations of clones were grown in the Negev, Israel in the Spring and Autumn seasons of three years, 1983, 1984 and 1985. Although symptoms of the diseases were seen in both seasons they were less severe in the Autumn. The effects of A. solani on yield, when expressed as percent of the control plot yield were also less in the Autumn than the Spring. With V. dahliae, however, the proportional effect on yield was greater in the Autumn. The decreases in yield associated with the two diseases were examined in terms of losses to the grower. The advantages of breeding for resistance/tolerance to these diseases were clear, emphasising the need for suitable screening techniques. © 1988 Kluwer Academic Publishers.