BIOLOGY AND PATHOGENICITY OF RHACODIELLA-CASTANEAE IN CHESTNUTS STORED AT LOW-TEMPERATURES

The growth and pathogenicity of Rhacodiella castaneae was studied on P DA and on inoculated and naturally infected chestnuts during storage a t 20, 10, 4, 2, 0, -2 and -4 degrees C. On PDA, the growth decreased w ith diminishing temperatures up to -2 degrees C, however, it stopped c ompletely at -4 degrees C. In vivo growth of the fungus was inhibited at -2 and -4 degrees C during 19 weeks of storage. Inoculated nuts kep t at 20 and 10 degrees C or at 4 and 2 degrees C had, within each temp erature range, a very similar incidence of rot. At 0 degrees C, the te mperature currently recommended for storage of chestnuts, no symptoms were detected up to 5 weeks in inoculated nuts and up to 6 weeks in na turally infected ones. But after 16 weeks, over 68 % of naturally infe cted nuts had rotted. Neither decay nor freezing injury was found in t he nuts kept at -2 and -4 degrees C during 19 weeks of storage.