CHANGES IN CONIDIAL MORPHOLOGY AND GERMINABILITY OF BOTRYTIS-ALLII AND PENICILLIUM-HIRSUTUM IN RESPONSE TO LOW-TEMPERATURE INCUBATION

Botrytis allii and Penicillium hirsutum spores, produced at 20, 10, 4, 0 and -2 degrees C on potato dextrose agar, showed a clearly inverse relationship between spore volume and incubation temperature. The spor e volumes of both B. allii and P.hirsutum were greatest at -2 degrees and smallest at 20 degrees. The mean volume of B. allii conidia produc ed at -2 degrees was 2 . 8 times larger than that of conidia produced at 20 degrees, whereas the volume of P. hirsutum doubled. When the spo res produced at different temperatures were incubated at 20, 10, 4, 0, -2 and -4 degrees, the large conidia from the lower temperature condi tions germinated much earlier and had a faster germ-tube growth than t he small ones, particularly when the temperature for spore germination was below 0 degrees.