First Report of Wood Canker Caused by Neoscytalidium dimidiatum on Grapevine in California

Abstract

In May 2012 in the Coachella valley, Riverside County, California, the decline of vines in table grape (Vitis vinifera) vineyards was observed. Foliar symptoms consisted of shoot blight with wilting and necrosis of leaves and drying and shriveling of berries. In some cases, the entire vine collapsed in the middle of the growing season (apoplexia). Wood cankers in the spurs, cordons, and trunks of affected vines were also present. The nine isolates recovered from the cankers were identified as Neoscytalidium dimidiatum (Penz.) Crous & Slippers based on morphological characteristics and DNA sequence comparisons. Two isolates were grown on potato dextrose agar (PDA) medium and a total of 50 conidia were measured per isolate. Conidia were ellipsoid to ovoid, with a truncate base and an acutely rounded apex, initially aseptate, becoming brown and two-celled at maturity, 7.2 ± 1.2 μm × 3.8 ± 0.4 μm. The rDNA internal transcribed spacer (ITS), and β-tubulin (BT) loci were amplified using primer pairs and methods previously described (4). A total of five isolates were sequenced. The DNA sequences of one N. dimidiatum grapevine isolate (UCR-Neo1) were deposited in the GenBank database (ITS, KC937066; BT, KC937067). Pathogenicity tests were performed by inoculating 12 grape cuttings cv. Thompson Seedless with isolate UCR-Neo1 and 12 control cuttings with sterile medium using a technique previously described (1). The experiment was repeated twice. After 20 weeks of incubation period in the greenhouse, the lesions length produced by N. dimidiatum averaged 13.5 mm and was significantly longer (P < 0.05) from the control (average 3 mm). N. dimidiatum was reisolated from all the inoculated plants and identified by colony morphology. The incidence of N. dimidiatum in table grape vineyards of the Coachella valley has been estimated at 15%, with nine vines infected out of 60 vines total. This pathogen has been identified in California in walnut nursery causing the death of trees due to the development of canker at the graft union (2). N. dimidiatum has also been identified as the causal agent of shoot blight, canker, and gummosis on citrus in Italy (3). The crop is also being grown in the Coachella valley and these findings warrant further investigation in order to determine the host range, distribution, and incidence of this pathogen in the area. References: (1) K. Baumgartner et al. Plant Dis. 97:912, 2013. (2) S. F. Chen et al. Plant Dis. 97:993, 2013. (3) G. Polizzi et al. Plant Dis 93:1215, 2009. (4) J. R. Urbez-Torres et al. Plant Dis. 92:519, 2008.

Flowering as the Most Highly Sensitive Period of Grapevine (Vitis vinifera L. cv Mourvèdre) to the Botryosphaeria Dieback Agents Neofusicoccum parvum and Diplodia seriata Infection

“…To date, at least 30 Botryosphaeriaceae species are known to infect grapevine [4,5,6,7,8,9]. Symptoms of Botryosphaeria dieback consist in woody tissues of grey sectorial necrosis with a brown stripe under the bark as well as typical foliar discolorations in white and red cultivars or wilting leaves in some cases [10,11].…”

Fruit rot caused by Neoscytalidium hyalinum on melon in Iran

“…have a wide geographical and host range. The symptoms include branch wilt, dieback, canker, leaf blight, gummosis and tree death (Polizzi et al 2009;Sakalidis et al 2011;Chen et al 2013;Rolshausen et al 2013;Correia 2016;Nurul Nadiah et al 2017).…”

Long-Term Benefits of Protecting Table Grape Vineyards against Trunk Diseases in the California Desert

“…Hence, high levels of Botryosphaeriaceae inoculum were previously trapped in the region with a significant positive correlation between irrigation and spore release [4]. This unique viticulture area is also known for hosting some of the most virulent GTD pathogens, including Botryosphaeriaceae species in the genera Lasiodiplodia and Neoscytalidium dimidiatum [34,35] that were recovered from the infected grapevine in our field trial. We also identified Phaeomoniella chlamydospora and Phaeoacremonium species the causal agents of esca disease that are widespread to all viticulture production areas worldwide [36], as well as species in the genus Eutypella, previously identified in the California desert area on citrus [37] and known to be pathogenic to grapevine [38].…”