Recovery of Alternaria brassicicola from Chopped, Bagged Kale (Brassica oleracea var. acephala)

Abstract

Alternaria brassicicola was found on pieces of chopped, bagged kale held 1 week beyond the typical postharvest storage period. Three of 11 Alternaria isolates were identified as A. brassicicola based on species-specific primers and multilocus genotyping with the translation elongation factor 1-alpha, RNA polymerase second largest subunit, and glyceraldehyde-3-phosphate dehydrogenase gene regions. Two isolates of A. alternata, two isolates of A. tenuissima, and four isolates comprising two unidentified species also were found. A. brassicicola also was found in a production field on the same farm. In the greenhouse, only A. brassicicola isolates caused disease on inoculated kale plants. As previously reported, A. brassicicola isolates had larger colony diameters on semiselective Chen and Wu medium than the nonpathogenic isolates. Black spot caused by A. brassicicola on kale leaves in the field can lead to black spot on harvested kale.