| Autor: |
Holland LA; Department of Plant Pathology, University of California, Davis, CA 95616.; Kearney Agricultural Research and Extension Center, Parlier, CA 93648., Trouillas FP; Department of Plant Pathology, University of California, Davis, CA 95616.; Kearney Agricultural Research and Extension Center, Parlier, CA 93648., Nouri MT; University of California Cooperative Extension San Joaquin County, Stockton, CA 95206., Lawrence DP; Department of Plant Pathology, University of California, Davis, CA 95616., Crespo M; Kearney Agricultural Research and Extension Center, Parlier, CA 93648., Doll DA; University of California Cooperative Extension Merced County, Merced, CA 95341., Duncan RA; University of California Cooperative Extension Stanislaus County, Modesto, CA 95358., Holtz BA; University of California Cooperative Extension San Joaquin County, Stockton, CA 95206., Culumber CM; University of California Cooperative Extension Fresno County, Fresno, CA 93710., Yaghmour MA; University of California Cooperative Extension Kern County, Bakersfield, CA 93307., Niederholzer FJA; University of California Cooperative Extension Colusa County, Colusa, CA 95932., Lightle DM; University of California Cooperative Extension Glenn County, Orland, CA 95963., Jarvis-Shean KS; University of California Cooperative Extension Sacramento, Solano, and Yolo Counties, Woodland, CA 95695., Gordon PE; University of California Cooperative Extension Madera County, Madera, CA 93637., Fichtner EJ; University of California Cooperative Extension Tulare County, Tulare, CA 93274. |
| Abstrakt: |
Almond canker diseases are destructive and can reduce the yield as well as the lifespan of almond orchards. These diseases may affect the trunk and branches of both young and mature trees and can result in tree death soon after orchard establishment in severe cases. Between 2015 and 2018, 70 almond orchards were visited throughout the Central Valley of California upon requests from farm advisors for canker disease diagnosis. Two major canker diseases were identified, including Botryosphaeriaceae cankers and Ceratocystis canker. In addition, five less prevalent canker diseases were identified, including Cytospora, Eutypa, Diaporthe, Collophorina, and Pallidophorina canker. Seventy-four fungal isolates were selected for multilocus phylogenetic analyses of internal transcribed spacer region ITS1-5.8S-ITS2 and part of the translation elongation factor 1-α, β-tubulin, and glyceraldehyde 3-phosphate dehydrogenase gene sequences; 27 species were identified, including 12 Botryosphaeriaceae species, Ceratocystis destructans , five Cytospora species, Collophorina hispanica , four Diaporthe species, two Diatrype species, Eutypa lata , and Pallidophorina paarla . The most frequently isolated species were Ceratocystis destructans , Neoscytalidium dimidiatum , and Cytospora californica . Pathogenicity experiments on almond cultivar Nonpareil revealed that Neofusicoccum parvum , Neofusicoccum arbuti , and Neofusicoccum mediterraneum were the most virulent. Botryosphaeriaceae cankers were predominantly found in young orchards and symptoms were most prevalent on the trunks of trees. Ceratocystis canker was most commonly found in mature orchards and associated with symptoms found on trunks or large scaffold branches. This study provides a thorough examination of the diversity and pathogenicity of fungal pathogens associated with branch and trunk cankers of almond in California. |
