Invasive Species Compendium

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Abstract

First report of leaf spot disease caused by Alternaria alternata on Carya illinoensis in China.

Abstract

Pecan (Carya illinoensis) is an important tree for commercial nut production in North America and widely cultivated in China. In September 2019, leaf spot symptoms were observed on the leaves of C. illinoensis in an ecologic orchard in Chuzhou, Anhui, China, with a disease incidence of 90[%]. The initial symptoms appeared as small circular to irregular dark brown or black spots on the leaves. The lesions enlarged and coalesced into large necrotic areas, which later resulted in leaf abscission and stunting. Disease symptoms were not observed on the fruits. The causal pathogen was isolated and identified as Alternaria alternata based on morphological characteristics, molecular data (sequence analysis of the internal transcribed spacer (ITS), 18S ribosomal RNA (SSU), 28S ribosomal RNA (LSU), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), translation elongation factor 1-alpha (TEF1), and anonymous region (OPA10-2) genes) and pathogenicity test. This is thought to be the first report of A. alternata associated with leaf spot disease on C. illinoensis in China.