Articles
The current status of trunk disease in Australian almond orchards
Article number
1406_47
Pages
327 – 336
Language
English
Abstract
Trunk diseases are caused by several organisms and are present in almond production regions worldwide.
These diseases can have a significant impact on orchard longevity and profitability.
Common symptoms of trunk diseases include necrosis of wood, discoloration of vascular tissues, extensive gumming, and decline and dieback of limbs from the point of infection.
Infection may kill scaffolds and the entire tree if left untreated.
Trunk disease symptoms were prevalent in all almond production regions in Australia, according to disease surveys conducted from 2018 to 2020. Samples from symptomatic trees yielded numerous fungal species identified using ITS4 and ITS1F primers.
Experiments were undertaken on almond trees (‘Carmel’) in pots to determine the pathogenicity of seven commonly isolated fungal species; Diplodia seriata, Eutypa lata, Colletotrichum acutatum, Collophora hispanica, Collophora rubra, Pleurostoma richardsiae, and Cytospora diatrypelloidea. Results revealed that all species caused disease, however, Cm. acutatum, E. lata and P. richardsiae were the only isolates that produced lesions larger than the control in all experiments.
It is likely that extrinsic factors influence canker development, including water stress, soil nutrients and temperature.
The susceptibility of cultivars to trunk disease pathogens was also investigated.
Experiments were carried out on potted almond trees (‘Nonpareil’, ‘Carmel’, ‘Wood Colony’, ‘Maxima’, ‘Carina’, and ‘Price’) to evaluate six almond cultivars commonly planted in Australia against five trunk pathogen species.
Cultivar susceptibility did not differ among pathogens.
Further investigation into factors influencing disease severity is necessary to refine management recommendations for the Australian almond industry.
These diseases can have a significant impact on orchard longevity and profitability.
Common symptoms of trunk diseases include necrosis of wood, discoloration of vascular tissues, extensive gumming, and decline and dieback of limbs from the point of infection.
Infection may kill scaffolds and the entire tree if left untreated.
Trunk disease symptoms were prevalent in all almond production regions in Australia, according to disease surveys conducted from 2018 to 2020. Samples from symptomatic trees yielded numerous fungal species identified using ITS4 and ITS1F primers.
Experiments were undertaken on almond trees (‘Carmel’) in pots to determine the pathogenicity of seven commonly isolated fungal species; Diplodia seriata, Eutypa lata, Colletotrichum acutatum, Collophora hispanica, Collophora rubra, Pleurostoma richardsiae, and Cytospora diatrypelloidea. Results revealed that all species caused disease, however, Cm. acutatum, E. lata and P. richardsiae were the only isolates that produced lesions larger than the control in all experiments.
It is likely that extrinsic factors influence canker development, including water stress, soil nutrients and temperature.
The susceptibility of cultivars to trunk disease pathogens was also investigated.
Experiments were carried out on potted almond trees (‘Nonpareil’, ‘Carmel’, ‘Wood Colony’, ‘Maxima’, ‘Carina’, and ‘Price’) to evaluate six almond cultivars commonly planted in Australia against five trunk pathogen species.
Cultivar susceptibility did not differ among pathogens.
Further investigation into factors influencing disease severity is necessary to refine management recommendations for the Australian almond industry.
Authors
B.J. Oswald, S. Kreidl, S.Q. Dinh, T.J. Wiechel, M.R. Sosnowski
Keywords
cultivar susceptibility, identification, pathogenicity, Prunus dulcis
Groups involved
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