Control of post-harvest decay of apples by pre-harvest and post-harvest application of ammonium molybdate

摘要

Ammonium molybdate was tested as a potential fungicide for use in apples (cv Golden Dlicious) against blue and grey mould, important post-harvest diseases of pome fruits. In tests in vivo at 20 deg C, ammonium molybdate (15mM) reduced lesion diameters of Penicillium expansum, Botrytis cinerea and Rhizopus stolonifer by 84%, 88% and 100% respectively. When apples treated with ammonium molynbdate were stored at 1 deg C for three months, a significant reduction in severty and incidence of P expansum and B cinereaa was observed in both years of study (1998 and 1999). In the second year of the experiment the reduction in disease severity was greater than 88% for both pathogens, and the level of control was similar, to, or greater than, that observed with the fungicide imazalil. When ammonium molybdate was applied as a pre-harvest treatment, a significant reduction in blue mould decay was onserved after three months in cold storage. In vitro, ammonium molybdate greatly inhibited spore germination of P expansum and B cinerea, although better inhibition was obtained against grey mould. Ammonium dimolybdate, sodium molybdate and potassium molybdate were also tested in vitro in comparison with ammonium molybdate as inhibitors of spore germination, but only ammonium molybdate inhibited spore germination by more than 50%.