VIEW ARTICLE

Postharvest Pathology and Mycotoxins

Postharvest Decay of Winter Pear and Apple Fruit Caused by Species of Penicillium. P. G. Sanderson, Oregon State University, Mid-Columbia Agricultural Research and Extension Center, Hood River 97031; R. A. Spotts, Oregon State University, Mid-Columbia Agricultural Research and Extension Center, Hood River 97031. Phytopathology 85:103-110. Accepted for publication 3 October 1994. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/Phyto-85-103.

In surveys conducted during two fruit packing seasons, P. expansum and P. solitum were recovered most frequently (65 and 96% of collections, respectively, in 1990–91, and 77 and 54% of collections, respectively, in 1991–92) and in highest densities (1,893 cfu/ml and 749 cfu/ml, respectively, in 1990–91, and 308 cfu/ml and 667 cfu/ml, respectively, in 1991–92) from pear and apple dump tank water. Penicillium solitum was collected most frequently (89% of collections) and in greatest concentrations (1,634 cfu/ml) from drench solutions followed by P. expansum and P. commune (47 and 42% of collections, respectively, and 495 cfu/ml and 249 cfu/ml, respectively). Penicillium expansum was recovered from about 27% of field bins sampled while P. solitum and P. commune were recovered from about 10 and 8%, respectively. Penicillium expansum and P. solitum were the Penicillium spp. most frequently recovered from fruit sampled from packinghouses and markets. Pear fruit were treated with 2 × 10² conidia per milliter of P. expansum in challenge inoculations 0, 1, 7, or 28 days following initial treatment with 2 × 10³ conidia per milliter of either P. solitum or P. commune to determine the competitive ability of P. expansum relative to these species. When incubated at 20 C for 7 days immediately following the challenge inoculation, P. expansum became established in wounds 0, 1, or 7 days following initial treatment with P. solitum and in water controls. Penicillium expansum did not become established in wounds challenged 28 days after initial treatments or in wounds challenged 7 days after initial treatment with P. commune. Incidence of infection by P. expansum following challenge inoculations 28 days after initial treatment with P. solitum was greater than in water controls when fruit were incubated at –1 C for 28 days followed by a ripening period of 7 days at 20 C. Incidence of infection by P. expansum generally decreased with increasing periods of time at which fruit were inoculated following initial wounding. Of 12 Penicillium spp. tested, only P. aurantiogriseum, P. commune, P. crustosum, P. expansum, P. griseofulvum, and P. solitum produced lesions in wounds of newly harvested, mature pear fruit (cv. d’Anjou).