LOW-TEMPERATURE BIOLOGY AND PATHOGENICITY OF PENICILLIUM-HIRSUTUM ON GARLIC IN STORAGE

Penicillium hirsutum grown on potato dextrose agar and kept at 20, 10, 4, 2, 0, -2 and -4 degrees C for 25 weeks revealed a longer lag phase at 0 degrees C and below, and its growth was reduced as the temperatu re was lowered. At -4 degrees C, the fungus showed slight lengthening of the hyphae only after 19 weeks. Sporulation and germination of coni dia were also delayed by low temperatures, and at -4 degrees C there w as no production or germination. All of the wounded and inoculated clo ves of 'Bianco Piacentino' garlic showed symptoms of blue mould diseas e after four weeks of storage at temperatures between 0 and 20 degrees C. At -2 degrees C, P. hirsutum colonised all of the cloves after sev en weeks, while at -4 degrees C they were all still healthy after 16 w eeks. No freezing injury was encountered at negative temperatures. A s torage temperature of -4 degrees C is advisable for the prevention of blue mould disease.