terclim by ICS banner
IVES 9 IVES Conference Series 9 Oospore germination dynamics and disease forecasting model for a precision management of downy mildew 

Oospore germination dynamics and disease forecasting model for a precision management of downy mildew 

Abstract

Downy mildew, caused by Plasmopara viticola, is the most economically impactful disease affecting grapevines. This polycyclic pathogen triggers both primary and secondary infection cycles, resulting in significant yield losses when effective disease control measures are lacking. Over the winter, the pathogen survives by forming resting structures, the oospores, derived from sexual reproduction, which produce the inoculum for primary infections. To optimize grapevine downy mildew control and obtain the desired levels of production while minimizing chemical inputs, it is crucial to optimize the timeframe for fungicide application. Disease forecasting models are useful to identify the infection risk. However, the prediction of primary infections is still a considerable challenge. A prior investigation revealed that the duration required for oospores to germinate (t) decreases as grapevines become susceptible to P. viticola. This study aimed to integrate oospore germination data with insights from the EPI forecasting model in ten vineyards located in Franciacorta, an important Italian viticultural area. The research was performed from grapevine sprouting (April) until bunch closure (July), over three consecutive years (2021-2023). Disease incidence and severity were assessed in untreated plots. Results indicated a simultaneous reduction in t corresponding to the infection risk signaled by the EPI model. A posteriori assessment highlighted the usefulness of biological data in defining the primary infection timing and the accuracy of the model in predicting the disease epidemics. In conclusion, the adoption of the EPI model integrated with the oospore germination assays significantly contributed to formulating a rational treatment strategy.

DOI:

Publication date: June 14, 2024

Issue: Open GPB 2024

Type: Poster

Authors

Giuliana Maddalena, Beatrice Lecchi*, Silvia Laura Toffolatti

Università degli Studi di Milano, Dipartimento di Scienze Agrarie e Ambientali – DISAA, Via Celoria 2, 20133 Milano

Contact the author*

Keywords

downy mildew, forecasting model, oospore germination, disease management, infection risk

Tags

IVES Conference Series | Open GPB | Open GPB 2024

Citation

Related articles…

Analysis of vineyard soil after mulching with municipal solid waste (MSW)-compost

The use of compost as amendment in agriculture is a well-established practice, strongly recommended for numerous benefits.

Contribution of grape seeds to evolution of acetaldehyde, pigments and tannins reactive towards salivary proteins of red wine over time

This study investigated the impact of the gsk/gse ratio on the evolution of acetaldehyde and of major phenolic compounds of aglianico wine in wine like solution and real wine. Four model solutions and the correspondant control wines were prepared. The natural weight ratio between grape skins and seeds was determined on the real grapes, and a control wine was obtained from those.

Chemical and biochemical formation of polysulfides in synthetic and real wines using UHPLC-HRMS

ulfur compounds in wine have been studied for several years due to their impact on wine flavour, but the role of polysulfides is a recent topic. Polysulfides in wine are formed when two sulfhydryl groups oxidize, especially in presence of elemental sulfur or metal catalysts from field treatment residues (Ugliano et al. 2011). These compounds are odourless, but can degrade during storage and affect the wine quality. The mechanism of their formation is still largely unknown but different chemical and biochemical pathways have been suggested. Disulfides from cysteine (Cys) and glutathione (GSH) have been revealed in model wines (Kreitman et al. 2016) and more recently also higher polymerized forms in real wines (Van Leeuwen et al. 2020). Volatile varietal thiols like 3-mercaptohexanol (3MH) and 4-mercaptopentanone (4MMP) – flavour compounds with tropical or fruity notes – could undergo similar reactions, also with Cys and GSH, subsequently losing their flavour property (fate). Even more concerning is the possible release of H2S from polysulfides during storage, leading to undesired off-flavours (Sarrazin et al. 2010).

Is it possible to approximate the technological and phenolic maturity of grapes by foliar application of elicitors?

The increase in the temperature and the more severe water stress conditions, trends observed in recent years as a consequence of climate change, are leading a mismatch between the technological and phenolic maturity of grapes

PERCEPTUAL INTERACTIONS PHENOMENA INVOLVING VARIOUS VOLATILE COMPOUND FAMILIES LINKED TO SOME FRUITY NOTES IN BORDEAUX RED WINES

Fruity notes play a key role in the consumer’s appreciation of Bordeaux red wines. If literature provides a lot of knowledge about the nature of volatile compounds involved in this fruity expression, the sensory phenomena involving these compounds in mixture still need to be explored. Considering previous sensory works about the impact of esters and some overripening compounds, the goal of this work was to study the implication of perceptual interactions involving red wine odorant compounds of diverse origins and described as potentially affecting fruity aromatic expression.