terclim by ICS banner
IVES 9 IVES Conference Series 9 Exploring zoxamide sensitivity in Plasmopara viticola populations: implications for fungicide management in precision agriculture

Exploring zoxamide sensitivity in Plasmopara viticola populations: implications for fungicide management in precision agriculture

Abstract

Fungicides play a critical role in managing grapevine downy mildew caused by the oomycete Plasmopara viticola, a biotrophic and polycyclic pathogen with a high risk of fungicide resistance. Zoxamide, categorized as a low to medium resistance risk, disrupts cell division by inhibiting tubulin polymerization. Resistance to zoxamide is uncommon in field isolates. This six-year study (2017-2022) aimed to detect and quantify zoxamide sensitivity in P. viticola populations across varying resistance pressures in Italian grapevine regions. Analysis of 126 samples from 57 vineyards, mainly in North-Eastern Italy, revealed that most samples exhibited EC50, EC95, and MIC values below 0.1 and 10 mg/L of zoxamide, respectively. Nineteen vineyards showed reduced sensitivity (MIC>100 mg/L), but only four samples were characterized by 24-54% resistant oospores at >100 mg/L of zoxamide. Notably, samples treated 4-5 times displayed a broader distribution of toxicological parameters, suggesting a heightened need to manage fungicide applications to reduce selection pressure. In conclusion, oospore assays proved valuable not only for detecting the overall sensitivity profile of populations but also for quantifying resistant individuals within them, enabling a better identification of critical factors affecting zoxamide sensitivity and highlighting the need for improved management practices in a precision agriculture context.

DOI:

Publication date: June 14, 2024

Issue: Open GPB 2024

Type: Poster

Authors

Mattia Peracchi1*, Beatrice Lecchi1, Giuliana Maddalena1, Silvia Laura Toffolatti1

1 Università degli Studi di Milano, Dipartimento di Scienze Agrarie e Ambientali – DISAA, Via Celoria 2, 20133 Milano2

Contact the author*

Keywords

plant disease, integrated pest management, disease control, fungicide resistance

Tags

IVES Conference Series | Open GPB | Open GPB 2024

Citation

Related articles…

Exploring the factors affecting spatio‐temporal variation in grapevine powdery mildew

The spatial distribution of powdery mildew is often heterogeneous between neighboring plots, with higher disease pressure in certain places

Bio‐metaethics viticulture proposed by the Giesco. Direct charter with producers. Example of evaluation of training systems

The key points of the current GiESCO charter ‘BIO‐MetaEthics’ are exposed. The new development in cooperation with Giovanni Cargnello is to apply the principles and the content into the practice by establishing a direct contract with producers and other actors of the wine sector. An evaluation sheet is proposed and tested in a new advanced vineyard. For illustrating the methodology of evaluation, the example of the choice of the training systems is detailed on a wide range of situations. 

Effect of the commercial inoculum of arbuscular mycorrhiza in the establishment of a commercial vineyard of the cultivar “Manto negro

The favorable effect of symbiosis with arbuscular mycorrhizal fungi (AMF) has been known and studied since the 60s. Nowadays, many companies took the chance to start promoting and selling commercial inoculants of AMF, in order to be used as biofertilizers and encourage sustainable biological agriculture. However, the positive effect of these commercial biofertilizers on plant growth is not always demonstrated, especially under field conditions. In this study, we used a commercial inoculum on newly planted grapevines of a local cultivar grafted on a common rootstock R110. We followed the physiological status of vines, growth and productivity and functional biodiversity of soil bacteria during the first and second years of 20 inoculated with commercial inoculum bases on Rhizophagus irregularis and Funeliformis mosseaeAMF at field planting time and 20 non-inoculated control plants. All the parameters measured showed a neutral to negative effect on plant growth and production. The inoculated plants always presented lower values of photosynthesis, growth and grape production, although in some cases the differences did not reach statistical significance. On the contrary, the inoculation supposed an increase of the bacterial functional diversity, although the differences were not statistically significant either. Several studies show that the effect of inoculation with AMF is context-dependent. The non-favorable effects are probably due to inoculation ineffectiveness under complex field conditions and/or that, under certain conditions, AMF presence may be a parasitic association. This puts into question the effectiveness of its application in the field. Therefore, it is recommended to only resort to this type of biofertilizer when the cultivation conditions require it (e.g., very low previous microbial diversity, foreseeable stress due to drought, salinity, or lack of nutrients) and not as a general fertilization practice.

Effects of water deficit on secondary metabolites in grapes and wines

In this video recording of the IVES science meeting 2021, Simone D. Castellarin (University of British Columbia, Wine Research Center, Wine Research Centre, Vancouver, Canada) speaks about the effects of water deficit on secondary metabolites in grapes and wines. This presentation is based on an original article accessible for free on OENO One.

Twenty-two shades of grey – An analysis of alcohol regulations in the Arab world

This article compares alcohol regulations across 22 Arab League member countries.