Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 5/30/2013
Publication Date: 6/30/2013
Citation: Wiseman, M.S., Dugan, F.M., Xiao, C. 2013. A postharvest fruit rot of apple caused by Lambertella sp. in Washington state. Phytopathology. 103:S2.160. Interpretive Summary:
Technical Abstract: During surveys for postharvest diseases of apples in 2003-05, a fruit rot disease was observed on stored apples collected from packinghouses. The disease appeared to originate from infections of wounds on the fruit, and lesions were brown and decayed tissues were spongy. Lambertella sp. was consistently isolated from the decayed fruit. Isolates differed from Lambertella corni-maris by only 0-2 base pairs in the sequences within the combined LSU, ITS, and SSU regions. The fungus grew at -0.5 to 25°C and formed apothecia on artificial media after ca. 8-24 weeks. On PDA under 12/12 light/darkness, apothecia were 1-2.75 mm in diameter with stipes of 1-4 mm x 0.5 mm. Asci were 76-125 x 3.5-5.5 µm, inoperculate, eight-spored, clavate, and narrowed at the base. Ascospores were aseptate, 7-10 x 2.5-4.5 µm, uniseriate to biseriate, and initially hyaline then changing to orange-brown within the ascus. Colony characteristics included: growth with little/no aerial mycelium, dark-yellow to gray-black in color, orange crystals secreted after 10-14 days, gray-black pseudosclerotia, and yellow pigmentation in the agar. Morphological characteristics of the fungus overlap with those of L. corni-maris. ‘Fuji’ apple fruit that were wounded, inoculated with representative isolates, and incubated at 0°C yielded the same symptoms, and the fungus was re-isolated from the diseased fruit. This is the first report of a fruit rot in apple caused by L. corni-maris in Washington State.