Spatial variation in response to 'reduced input' spray programs for powdery mildew and botrytis identified through whole-of-block experimentation

Background and Aims: Previous work has highlighted the utility of the whole-of-block approach to viticultural experimentation. Here, we use this approach as a means of evaluating alternative spray programs for managing two economically important grapevine diseases at commercial scale. Methods and Results: Two experiments were conducted in vineyards in the Coal River and Rokeby districts of Tasmania. The first, carried out in a 4.5 ha vineyard planted to Vitis vinifera L. cv. Pinot Noir, sought to evaluate fungicide programs for control of powdery mildew ( Erysiphe necator ), in particular with a view to reducing the amount of sulphur applied in organic production systems. The second sought to evaluate the benefit (if any) of changing the time of fungicide application from flowering to pre-bunch closure for the control of botrytis bunch rot ( Botrytis cinerea ) in a 2.4 ha Chardonnay vineyard. In both cases, treatments were applied to a whole-of-block experimental design using commercial spray equipment. Disease severity and the response to the various spray treatments, was spatially variable and related to topographic variation. Botrytis severity was also related to vine vigour. The powdery mildew results supported the retention of sulphur in organic spray programs, while Switch® (Syngenta Group, Basel, Switzerland) applied at pre-bunch closure in the botrytis experiment reduced disease severity relative to the application at flowering. Spatial variation in the response to the latter treatment, when examined four times pre-harvest, suggested that secondary spread may not have been an important mechanism for increasing disease severity over time. Conclusions: Consistent with the other work described in this series of papers, we conclude that the whole-of-block experimental approach offers both researchers and vineyard managers a means of acquiring more useful information than would be obtained from a conventional plot-based approach. Significance of the Study: This study highlights the value of collecting spatially distributed data as a means of better understanding the incidence, spread, progression and control of fungal grapevine diseases. As such, it provides a new application for this experimental approach, which enables spatial variability to be used as an experimental tool.

[1]  T. Michailides,et al.  EPIDEMIOLOGY OF BOTRYTIS CINEREA IN ORCHARD AND VINE CROPS , 2007 .

[2]  R. M. Lark,et al.  The geostatistical analysis of experiments at the landscape-scale , 2006 .

[3]  M. Doster,et al.  Effects of leaf maturity and cultivar resistance on development of the powdery mildew fungus on grapevines , 1985 .

[4]  K. Evans,et al.  Disease Assessment and Epidemic Monitoring Methodology for Bunch Rot ( Botrytis Cinerea ) in Grapevines , 2006 .

[5]  M. Hutchinson.  A new procedure for gridding elevation and stream line data with automatic removal of spurious pits , 1989 .

[6]  Susan L. Ustin,et al.  Grapevine dormant pruning weight prediction using remotely sensed data , 2003 .

[7]  R. Lark,et al.  Geostatistics for Environmental Scientists , 2001 .

[8]  L. Willocquet,et al.  Effects of radiation, especially ultraviolet B, on conidial germination and mycelial growth of grape powdery mildew , 1996, European Journal of Plant Pathology.

[9]  R. E. Smart,et al.  Sunlight into wine , 1991 .

[10]  Eileen S. Scott,et al.  Effects of powdery mildew on the sensory properties and composition of Chardonnay juice and wine when grape sugar ripeness is standardised , 2005 .

[11]  G. N. Hill,et al.  Tools for accurate assessment of botrytis bunch rot (Botrytis cinerea) on wine grapes. , 2010 .

[12]  P. Darriet,et al.  Characterization of some mushroom and earthy off-odors microbially induced by the development of rot on grapes. , 2006, Journal of agricultural and food chemistry.

[13]  R.G.V. Bramley,et al.  Precision Viticulture: Managing vineyard variability for improved quality outcomes , 2022, Managing Wine Quality.

[14]  W. Wilcox,et al.  Ontogenic resistance to powdery mildew in grape berries. , 2003, Phytopathology.

[15]  W. Hewitt,et al.  Early Botrytis rot of grapes: time of infection and latency of Botrytis cinerea Pers. in Vitis vinifera L. , 1973 .

[16]  B. G. Coombe,et al.  Growth Stages of the Grapevine: Adoption of a system for identifying grapevine growth stages , 1995 .

[17]  R. M. Lark,et al.  Spatio-temporal variability of some metal concentrations in the soil of eastern England, and implications for soil monitoring. , 2006 .

[18]  C. Huffaker,et al.  Predator [Metaseiulus occidentalis] — Prey [Pronematus spp.] interactions under sulfur and cattail pollen applications in a noncommercial vineyard , 1974, Entomophaga.

[19]  P. Grbin,et al.  Sustainable Control of Powdery and Downy Mildew Diseases of Grapevine and Impacts of Control on Wine Quality and Vineyard Health , 2008 .

[20]  R. Bramley,et al.  Understanding variability in winegrape production systems 2. Within vineyard variation in quality over several vintages , 2005 .

[21]  R. G. V. Bramley,et al.  Enhancing the value of field experimentation through whole-of-block designs , 2010, Precision Agriculture.

[22]  M. Hubert,et al.  A Robust Measure of Skewness , 2004 .

[23]  P. Crisp,et al.  An evaluation of biological and abiotic controls for grapevine powdery mildew. 2. Vineyard trials , 2006 .

[24]  R. Bramley,et al.  Vineyard variability in Marlborough, New Zealand: characterising variation in vineyard performance and options for the implementation of Precision Viticulture , 2011 .

[25]  M. Hubert,et al.  A Comparison of Some New Measures of Skewness , 2003 .

[26]  R. Bramley,et al.  Understanding variability in winegrape production systems , 2004 .

[27]  B. Tisseyre,et al.  The potential of high spatial resolution information to define within-vineyard zones related to vine water status , 2008, Precision Agriculture.

[28]  R. Bramley,et al.  Viticultural experimentation using whole blocks: evaluation of three floor management options , 2011 .

[29]  A. Lakso,et al.  Influence of powdery mildew on yield and growth of Rosette grapevines. , 1984 .

[30]  Brett Whelan,et al.  Establishing Management Classes for Broadacre Agricultural Production , 2007 .

[31]  H. Bleiholder,et al.  Growth Stages of the Grapevine: Phenological growth stages of the grapevine (Vitis vinifera L. ssp. vinifera)—Codes and descriptions according to the extended BBCH scale† , 1995 .

[32]  R. Bramley,et al.  Vineyard variability in Marlborough, New Zealand: characterising spatial and temporal changes in fruit composition and juice quality in the vineyard , 2011 .