Use of nitrate non-utilizing (nit) mutants to determine phenological stages at whichBotrytis cinereainfects wine grapes causing botrytis bunch rot

Botrytis bunch rot (botrytis) can reduce grape yield and wine quality Standardised assessment methods are needed to allow greater precision in wine making and to allow the use of disease management decision support models in grape production This study developed a botrytis disease assessment key to assist the accuracy of visual disease assessment Associated computer training software designed to improve the accuracy of disease assessments was also developed and tested The mean absolute error in estimates of percentage botrytis severity was significantly (P

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Diversity, Pathogenicity, and Fungicide Sensitivity of Fungal Species Associated with Late-Season Rots of Wine Grape in the Mid-Atlantic United States

Plant Disease ◽

10.1094/pdis-01-21-0006-re ◽

2021 ◽

Author(s):

Scott David Cosseboom ◽

Mengjun Hu

Keyword(s):

United States ◽

Detrimental Effect ◽

Field Trials ◽

Fungal Species ◽

Wine Grape ◽

Wine Grapes ◽

Phenological Stages ◽

Fungicide Sensitivity ◽

Late Season ◽

Higher Sensitivity

Late-season bunch rots cause major losses in grape production every year in the Mid-Atlantic United States, but the causal agents are not well characterized. In this study, 265 fungal isolates were collected from rotten grapes from 2014 to 2020 and identified to the genus level according to ITS sequences. The most prevalent of the 15 genera were Botrytis, Colletotrichum, Aspergillus, Alternaria, Pestalotiopsis, and Neopestalotiopsis. Of these, isolates within three prevalent, yet understudied genera were identified to be Aspergillus uvarum, Alternaria alternata, and Neopestalotiopsis rosae. The pathogenicity of these three fungal species was evaluated in two field trials by artificially inoculating wounded and non-wounded grapes of four cultivars at the phenological stages of bloom, veraison, and pre-harvest. Upon ripening, fruit were weighed and assessed for severity of multiple diseases. On non-wounded fruit, A. uvarum caused significantly higher disease severity than the control in both seasons. On wounded fruit, each inocula caused significantly higher disease than the respective controls in the first season, but only A. uvarum and B. cinerea caused this in the second season. Also, wounding was found to have a detrimental effect on cluster weight, which was significantly influenced by inoculation timing and cultivar. Lastly, A. uvarum and N. rosae were tested for sensitivity to azoxystrobin, boscalid, and difenoconazole. The A. uvarum isolates were found to be more sensitive to boscalid and difenoconazole in general, with varying sensitivity to azoxystrobin. N. rosae isolates were resistant to boscalid and azoxystrobin but displayed much higher sensitivity to difenoconazole. Evidence from the isolate collection and field trials demonstrates that A. uvarum could be a significant pathogen of wine grapes in the Mid-Atlantic. Results from this study will be useful for the identification and management of the understudied Alternaria, Aspergillus, and Neopestalotiopsis fruit rots of wine grapes.

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Leaf Removal for Control of Botrytis Bunch Rot of Wine Grapes in the Midwestern United States

Plant Disease ◽

10.1094/pd-77-1224 ◽

1993 ◽

Vol 77 (12) ◽

pp. 1224 ◽

Cited By ~ 16

Author(s):

J. T. English

Keyword(s):

United States ◽

Leaf Removal ◽

Wine Grapes ◽

Midwestern United States ◽

Bunch Rot

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Patterns of Root Growth in Grape and Apple in Relation to Shoot Phenology

HortScience ◽

10.21273/hortsci.40.4.1146a ◽

2005 ◽

Vol 40 (4) ◽

pp. 1146A-1146 ◽

Cited By ~ 1

Author(s):

David M. Eissenstat ◽

Denise Neilsen ◽

Alan N. Lakso ◽

David R. Smart ◽

Taryn L. Bauerle ◽

...

Keyword(s):

Root Growth ◽

Carbon Allocation ◽

Bimodal Distribution ◽

Considerable Variability ◽

Wine Grapes ◽

Phenological Stages ◽

Napa Valley ◽

Harvest Timing ◽

Shoot Phenology ◽

Root Observation

Growers plan most of their horticultural activities around certain shoot phenological stages, such as bloom, veraison, and harvest. Timing of root growth in relation to these stages of the shoot is of interest in fertilization scheduling and in understanding carbon allocation demands of the root system. With the recent use of minirhizotron root observation tubes, a much greater understanding of patterns of root growth has been made possible. In Fredonia, N.Y., 5 years of root investigation in `Concord' grape indicate considerable variability in timing of root flushes. Root flushes could occur any time between bloom and veraison, but were generally not observed after harvest. Wine grapes in the Napa Valley exhibited similar patterns. In apple, root flushes may occur at bloom, but often not after harvest. Consequently, we rarely observed the bimodal distribution of root flushes commonly depicted in textbooks for apple and grape. Our data suggest that general perceptions of the timing of root growth may be in error.

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A review of the direct and indirect effects of nitrogen on botrytis bunch rot in wine grapes

New Zealand Plant Protection ◽

10.30843/nzpp.2008.61.6841 ◽

2008 ◽

Vol 61 ◽

pp. 306-310 ◽

Cited By ~ 4

Author(s):

D.C. Mundy

Keyword(s):

Indirect Effects ◽

Metabolic Pathways ◽

Nitrogen Nutrition ◽

Integrated Management ◽

Quality Parameters ◽

Management Systems ◽

Direct And Indirect Effects ◽

Wine Grapes ◽

Berry Quality ◽

Bunch Rot

Nitrogen is an important macronutrient for grapevines influencing a number of metabolic pathways and plant structures This review provides a summary of some direct and indirect effects of nitrogen fertilisation on bunch rot incidence in the field Direct changes due to increased nitrogen nutrition include greater thickness of the wax on berry surfaces and increased concentrations of the biochemical defence compounds produced in them Indirect changes that result from increased nitrogen include development of tighter bunches and denser canopies As integrated management systems become more complex a better understanding of different components such as nitrogen nutrition is required to allow vineyard managers to make informed decisions on how potential changes to current practices may influence disease and berry quality parameters

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Development of biologicallybased products for control of Botrytis in wine grapes

New Zealand Plant Protection ◽

10.30843/nzpp.2009.62.4834 ◽

2009 ◽

Vol 62 ◽

pp. 397-397

Author(s):

P.A.G. Elmer ◽

F.J. Parry ◽

T. Reglinski

Keyword(s):

New Zealand ◽

Natural Product ◽

Biological Product ◽

Wine Grapes ◽

Crop Losses ◽

Late Season ◽

Food Research ◽

Product Formulation ◽

Excellent Control ◽

Bunch Rot

Bunch rot of grapes caused by Botrytis cinerea is responsible for crop losses exceeding 30 under favourable disease conditions The potential for greater losses exists due to a marketdriven industrywide shift towards nil pesticide residues spray programmes Plant Food Research is developing nil residue biological and natural products in partnership with New Zealand Winegrowers Technology New Zealand the Foundation for Research Science and Technology and BotryZen Limited The biological product BOTRYZen based upon Ulocladium oudemansii (Patent PCT/NZ01/00111) is applied early season for control of Botrytis and ARMOURZen a chitosanbased natural product formulation is applied mid and late season and complements BOTRYZen Two developmental products NP2 (PCT/NZ2005/000167) and BCAL1 have provided excellent control of Botrytis during mid to late season NP2 is a plantbased natural product suitable for use mid season while BCAL1 colonises the berry surface thereby preventing Botrytis infection preharvest These field trial results demonstrate that nil residue full season biological control of Botrytis is achievable with crop losses being similar to those under current fungicidebased spray programmes

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