First Report of Cryptovalsa ampelina and Eutypella leprosa Associated with Grapevine Trunk Diseases in Chile

Abstract

Trunk diseases (TD) of grapevines (Vitis vinifera L.) have increased considerably in Chile with an incidence of more than 25% found in ≥7-year-old vineyards. Only species of Botryosphaeriaceae, Phaeoacremonium, and Phaeomoniella were associated with TD in Chile (1,2). From 2009 to 2010, isolations were made from the grapevines ‘Cabernet Sauvignon’, ‘Carmenere’, ‘Flame Seedless’, and ‘Pinot Noir’ collected in central Chile (33°27′ to 34°39′S, 71°17′ to 71°33′W). These grapevines showed cankers and vascular necrosis of trunks, arms, and spurs along with a general decline and dieback. Isolations were performed in potato dextrose agar (PDA) plus 0.005% tetracycline, 0.01% streptomycin, and 0.1% Igepal CO-630 (Sigma-Aldrich, St. Louis, MO), for 14 days at 20°C. On the basis of colony morphology and conidia production, two Libertella-like species were obtained in 26 (7.8%) of 335 trunk samples. On the basis of the internal transcribed spacer region (ITS4 and ITS5) of rDNA, Cryptovalsa ampelina (Nitschke) Fuckel (GenBank Accession Nos. HQ694976 and HQ694977), and Eutypella leprosa (Persoon) Berlese (HQ694974 and HQ694975) were identified, showing 98 to 100% similarity with the sequences of C. ampelina (GQ293913) and E. leprosa (AJ302463.1). C. ampelina produced white-to-creamy, smooth colonies with a creamy underside. Colonies of E. leprosa were white-to-gray with a white underside. Orange conidial masses were exuded after 30 days at 20°C. Conidia on PDA (n = 20) were unicellular, hyaline, filiform, slightly curved, and (19.8) 23.4 ± 2.6 (28.3) × (1.1) 1.4 ± 0.2 (1.8) μm and (19.2) 23.9 ± 3.0 (27.6) × (1.0) 1.2 ± 0.1 (1.5) μm for E. leprosa and C. ampelina, respectively. Stromatic perithecia of C. ampelina, embedded in the bark, were observed in dead pruning residues of infected vines (4). Pathogenicity tests were conducted with two isolates of each species, on 30-day-old ‘Carmenere’, rooted in vitro (n = 12), that were inoculated by placing a 5-mm agar plug on the surface of the propagation medium. Additionally, 15 cm long pieces (n = 5) of 1-year-old canes from ‘Carmenere’, ‘Chardonnay’, and ‘Red Globe’ were inoculated by placing a 5-mm agar plug underneath a cut aseptically made in each cane. An equal number of noninoculated plants and canes, but treated with sterile agar plugs, were used as controls. Leaf number (LN), shoot length (SL), and root length (RL) were assessed on plants in vitro after 28 days at 20°C. The extent of vascular discoloration (VD) obtained in canes was determined after 45 days in humid chambers at 20°C. One-way analysis of variance was performed and mean differences were studied by Tukey's test. C. ampelina and E. leprosa significantly (P < 0.05) reduced the LN, SL, and RL relative to the control plants. They also caused a VD of 10.1, 11.6, and 9.8 mm and 11.2, 13.4, and 10.0 mm in ‘Carmenere’, ‘Chardonnay’, and ‘Red Globe’, respectively. No symptoms were observed on the control canes. C. ampelina (100%) and E. leprosa (75%) were reisolated from inoculated plants and canes. To our knowledge, this is the first report of C. ampelina and E. leprosa on grapevines in Chile. However, their relative importance as causal agent of trunk disease remains to be determined. C. ampelina and E. leprosa have been associated with grapevine cankers in the United States and Spain (3,4). References: (1) J. Auger et al. Plant Dis. 88:1285, 2004. (2) J. Auger et al. Plant Dis. 88:1286, 2004. (3) M. T. Martin et al. Plant Dis. 93:545, 2009. (4) F. P. Trouillas et al. Mycologia 102:319, 2010.

Duration of the susceptibility of pruning wounds of different ages to infections by Phaeomoniella chlamydospora on grapevine cv. Cabernet Sauvignon in Central Chile

“…In this sense, several works have evaluated the effect of early versus late pruning on the level of infection of pruning wounds, where late pruning (February-March) can reduce the risk of infection to P. chlamydospora , because early pruning (December-January) coincides with the peak of spore release and the presence of the first rains of the season that generally occur in California ( Eskalen and Gubler, 2001 ). Similarly, these results were also found with E. lata and P. chlamydospora , where early pruning inoculations showed higher levels of spurs infected in France ( Chapuis et al., 1998 ) and Italy ( Serra et al., 2008 ), respectively. This is in contrast to the results obtained by Luque et al.…”

“…Previous studies performed in vineyards with inoculation of fungal trunk pathogens, including Eutypa lata , Botryosphaeriaceae, and P. chlamydospora on pruning wounds, have shown that the susceptibility was highest to infection when the inoculation was done on fresh pruning wounds (the first two weeks), but the susceptibility decreased on the wounds when the time between pruning wounds and inoculation increased ( van Niekerk et al., 2011 ; Úrbez-Torres and Gubler, 2011 ; Elena and Luque, 2016 ). Moreover, according to studies on the grapevine, the pruning wounds inoculated with P. chlamydospora can be susceptible for a period extended up to 4 to 16 weeks after pruning from vineyards in California ( Eskalen et al., 2007 ), France ( Chapuis et al., 1998 ), Italy ( Serra et al., 2008 ), South Africa ( van Niekerk et al., 2011 ) and Spain ( Elena and Luque, 2016 ). For the development of a strategy in the management of the GTDs, studies about the duration of pruning wounds are important to elucidate aspects such as time for protection with fungicides and biological agents according to the susceptibility of pruning wounds.…”

Biodiversity of pathogenic wood fungi isolated from <em>Xylotrechus arvicola</em> (Olivier) galleries in vine shoots

“…On the other hand, the co-occurrence of P. viticola and E. lata has been hypothesized in explaining variation in the development of grapevine dieback (Péros et al, 1999). The fungus C. ampelina, isolated only from one vine sample, has also been associated with grapevine decline in Spain and Chile (Martin et al, 2009 ;Díaz et al, 2011), although it does not appear to be a major pathogen because of its low virulence.…”

Grapevine trunk diseases: complex and still poorly understood

“…Recently, new species have been described in Australia ( Eutypella microtheca , Eutypella citricola and Diatrypella vulgaris ; Trouillas et al. , 2011) and in Chile ( Eutypella leprosa ; Diaz et al. , 2011).…”