Microbial population dynamics on Golden Delicious apples from bud to harvest and effect of fungicide applications.
Teixido, N.; Usall, J.; Magan, N.; Vinas, I.;
Annals of Applied Biology Year: 1999 Vol: 134 Issue: 1 Pages: 109-116 Ref: 41 ref.
1999
บทคัดย่อ
The microbial population dynamics on apples (cv. Golden Delicious) were analysed every 15 days between bud and harvest in Aitona, Spain, in 1994 and 1995. The total microbial populations varied with developmental stage and with prevailing climatic conditions. The predominant mycroflora were the filamentous fungi Cladosporium and Alternaria spp. and white and pink yeasts. Other genera isolated included mainly species of Epicoccum, Fusarium and Acremonium. However, the most important post-harvest pathogens Penicillium expansum and Botrytis cinerea were seldom isolated from ripening apples. Maximum total filamentous fungal populations occurred after fruit set and during early ripening (approx. 2x104 colony forming units
g) while bacterial populations were maximum at bud stage (3.5x105 and 3.0x104 colony forming units/g in 1994 and 1995, respectively). White yeasts were more numerous than pink yeasts. Endophytic infection of apple buds by Alternaria spp. was found in almost all bud tissue. Cladosporium spp. were initially isolated from 12.5-50% of tissue samples during blooming and fruit set. The impact of a 4-spray fungicide regime during apple development significantly decreased the total filamentous fungal populations in both years. However, bacterial populations were often higher on apples from fungicide-treated plots. Fungicide sprays decreased populations of Cladosporium, Alternaria and white yeasts for a maximum of up to 15-30 days after application. Fungicide application had little effect on endophytic infection of apples by Alternaria spp. between bud and harvest.