Epidemiology, identification and disease management of grape black rot and potentially useful metabolites of black rot pathogens for industrial applications – a review
D. Molitor, and M. Beyer
Annals of Applied Biology, vol. 165, no. 3, pp. 305-317, 2014
Phyllosticta ampelicida (teleomorph: Guignardia bidwellii) is the fungal plant pathogen that causes black rot on grapevine. It is able to infect all green, expanding grape tissues. Black rot poses a threat to both yield and wine quality; a severe attack can virtually cause a complete crop loss. The fungus is native to North America, and was spread to Europe at the end of the 19th century. With the beginning of the 21st century, an increasing importance of the disease was observed in several European winegrowing regions. Successful black rot control strategies combine sanitary measures, cultural techniques, growing cultivars with reduced susceptibility and the use of effective fungicides. Berries are most susceptible to infections between flowering and bunch closure and consequently, fungicide applications against black rot need to focus on this period. In this paper, forecast models and decision support systems that help to achieve satisfactory control with a minimum of fungicide input are presented. Black rot in grapevine was reported to be well controlled in field experiments by a broad range of fungicide classes including quinone outside inhibitors (98 ± 3% efficacy), demethylation inhibitors (98 ± 3% efficacy) and dithiocarbamates (92 ± 7% efficacy). Average efficacies of other fungicide classes tested so far ranged from 32 to 69%; meta data on the efficacy of fungicides in numerous field trials are given. At present, black rot causes major problems primarily if vineyard management and fungicide use were reduced or abandoned. Organically managed vineyards are highly affected. Hence, site and cultivar selection as well as cultural measures are of the highest importance especially in organic viticulture. Recent studies showed that some strains formerly classified as G. bidwellii in fact belong to a distinct species (P. parthenocissi). Black rot pathogens produce some phytotoxic secondary metabolites, such as phenguignardic acid, guignardic acid, alaguignardic acid and the guignardianones A, E and F, which could stimulate the development of new herbicides of natural origin.