Phomopsis viticola

Genus/species: Phomopsis viticola

 

Classification: Ascomycete

Morphology:

  • Cell: Growth is in the form of hyphae (cell with filamentous, tubular cell wall containing chitin) which, when connected together, form what is called a mycelium.
  • Colony:  Malt agar: Produce raised colonies with growth rings. Dark pycnidia are produced over time
  • Spore: Both fusiform and filiform spores can be present in the cirrhi which are mucus-bound groups of spores that take the form of a ribbon.
  • Ascus: single-walled
  • Liquid Growth:

Physiological Traits:

Sugar and amino acids from berries are used as nutrient sources.

Ecological Traits:

Found in all viticultural areas and specifically does well in wet climates.

Distinguishing Features:

Can be identified on the vine by dark necrotic spots surrounded by a halo of yellow, dying tissue.

Main control method is to use certified wood and avoid introducing the disease to the vineyard by maintaining strict hygiene practices. Leaf removal in the fruiting zone can also inhibit the fungi from establishing itself on the berries due to unrestricted airflow.

Protectant fungicides: mancozeb, captan, ziram. (Erincik, 2002)

Role in wine:

It is a grapevine disease agent and infects all green parts of the vine producing necrotic areas on the grapevine. This leads to girdling of portions of the vine and yield losses. When berries become infected, there is a decrease in quality of the fruit.

Sensitivities:

  • Sulfur spray: Some inhibition
  • Sorbate­­­­­: NA
  • DMDC: NA
  • pH: NA
  • Acids: NA
  • Ethanol: NA
  • Anaerobiosis: NA
  • Heat: Can be effective if cuttings are heat treated before planting.

References:

  • Burges, N. Taylor, A. Kumar, S. Phomopsis Cane and Leaf Spot. Department of Agriculture, The State of Western Australia. No. 9. 2005.
  • Erincik, O., Madden, L. V., Ferree, D. C., Ellis, M. A. Infection of grape berry and rachis tissues by Phomopsis viticola.Online. Plant Health Progress doi:10.1094/PHP-2002-0702-01-RS. 2002.
  • Úrbez-Torres, J. Adams, P. Kamas, J. Gubler, W. Identification, Incidence, and Pathogenicity of Fungal Species Associated with Grapevine Dieback in Texas. Am. J. Enol. Vitic. 60:4:497-507 2009.
  • Kassemeyer, H. Berkelmann-Lohnertz, B. Biology of Microorganisms on Grapes, in Must and in Wine. Springer-Verlag Berlin Heidelberg. Pgs. 61-85. 2009.
  • “(F) 42-day-old colony morphology of P. viticola (UCD2408TX). Mucilaginous light-cream exudation (cirrhi) can be observed from pycnidia. (G) P. viticola alpha (oval and elliptical) and β (filiform and mostly curved) conidia (UCD2408TX). Scale bar, 10 µm.” (Úrbez-Torres et al. 2009)