Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

First report of Alternaria alternata causing hybrid hazel (Corylus heterophylla × C. avellana) fruit drop in China.

Abstract

Previously undocumented apical necrosis has been observed in hybrid hazels (Corylus heterophylla × C. avellana) since 2012, causing premature fruit drop rates of up to 60% and leading to major economic losses in China. Hazelnut apical necrosis is also an important production problem in Italy. To explore the cause of hazelnut apical necrosis, 352 isolates were extracted from 150 fruits with external symptoms. Fruits were surface-disinfected, rinsed in sterile water, plated, and incubated for one week (25°C, 16/8 h light/dark), after a June to August 2015 collection from trees and below-canopy ground at 5 hybrid-hazel orchards in Jilin Province. Based on morphological characteristics, molecular data (PCR amplification and sequencing of rDNA ITS, endopolygalacturonase gene and OPA1-3 (anonymous region of A. alternata genome)) and pathogenicity tests, the causal agent was identified as A. alternata. This is thought to be the first report linking A. alternata to an internal form of hazelnut apical necrosis in China.