Grapevine trunk diseases of cold-hardy varieties grown in Northern Midwest vineyards coincide with canker fungi and winter injury

Abstract

Grapevine trunk diseases make up a disease complex associated with several vascular fungal pathogenic species. Surveys to characterize the composition of grapevine trunk diseases have been conducted for most major grape growing regions of the world. This study presents a similar survey characterizing the fungi associated with grapevine trunk diseases of cold-hardy interspecific hybrid grape varieties grown nearly exclusively in the atypical harsh winter climate of Northern Midwestern United states vineyards. From the 172 samples collected in 2019, 640 isolates obtained by culturing were identified by ITS sequencing and represent 420 sample-unique taxa. From the 420 representative taxa, opportunistic fungi of the order Diaporthales including species of Cytospora and Diaporthe were most frequently identified. Species of Phaeoacremonium, Paraconiothyrium, and Cadophora were also prevalent. In other milder Mediterranean growing climates, species of Xylariales and Botryosphaeriales are often frequently isolated but in this study they were isolated in small numbers. No Phaeomoniellales taxa were isolated. We discuss the possible compounding effects of winter injury, the pathogens isolated, and management strategies. Additionally, difficulties in researching and understanding the grapevine trunk disease complex are discussed.

Fungal species associated with grapevine trunk diseases in Washington wine grapes and California table grapes, with novelties in the genera Cadophora, Cytospora, and Sporocadus

“…In Washington vineyards, Cytospora viticola was found at two sites on four distinct cultivars, and in California, it was found at three sites and three cultivars. This is a first report of Cytospora viticola in these two states; this species was previously reported causing Cytospora canker in vineyards from the northeastern US (US states of Connecticut, Michigan, Minnesota, New York, Ohio, Vermont, Virginia, and Wisconsin), and southeastern Canada (Canadian provinces of Ontario and Quebec) (Lawrence et al, 2017a;Dekrey et al, 2022). Our results of controlled inoculations confirmed Cytospora viticola as pathogenic to grapevine wood and support Cytospora canker as a grapevine trunk disease.…”

“…Members of the genus Cytospora include species that cause cankers on a range of horticultural crops, and Cytospora canker is recognized as a common disease in many fruit and nut crops (Adams et al, 2002;Fan et al, 2015;Lawrence et al, 2018a). However, Cytospora species are not frequently reported causal fungi of grapevine trunk diseases [see Fotouhifar et al (2010); Lawrence et al (2017a) and Dekrey et al (2022). In Washington vineyards, Cytospora viticola was found at two sites on four distinct cultivars, and in California, it was found at three sites and three cultivars.…”

Hybrid Vitis Cultivars With American or Asian Ancestries Show Higher Tolerance Towards Grapevine Trunk Diseases

“…Since most of the GTD pathogens are wound-colonizing fungi, frost cracks of the wood parts of the plant could facilitate the prevalence of the GTD disease complex in grapevine [67,68]. Compared to V. vinifera and V. labrusca species, V. amurensis is extraordinarily cold-resistant and can survive long and cold winters as a result of its relatively low respiratory intensity, a lower level of active metabolism and a longer dormancy period [32].…”

Susceptibility of fig cultivars to Diaporthe canker in Iran

“…The effects of abiotic stress on the development of canker have been evaluated in several previous studies (Agustí‐Brisach et al, 2020; DeKrey et al, 2022). In recent years, Middle East countries, particularly Iran, have experienced periods of increased intense droughts and uneven rainfall (Mansouri Daneshvar et al, 2019).…”