First assessment of Goidanich Index and aerobiological data forPlasmopara viticolainfection risk management in north-west Spain

Abstract

The climate of north-western Spain, with high temperatures and relative humidity during the grapevine vegetative cycle, can especially favour the development of fungal diseases in vineyards. One of the most important diseases is downy mildew, caused by the fungus Plasmopara viticola. The aim of the current study is to propose a system containing phenological data, biological sensors of pathogen indicator and the agrometeorological Goidanich Index in order to optimize the application of downy mildew fungicide treatments. The study was conducted in a vineyard of the ‘Ribeiro’ Designation of Origin region from 2005 to 2016 during the Vitis vegetative period. Aerobiological sampling was performed using a LANZONI VPPS-2000 volumetric trap. The highest number of infection cycles was recorded during the 2009 harvest, with a total of 16 cycles. Years with fewer infection cycles were 2008, 2011 and 2012 (13 cycles). Primary infections were produced during the third fortnight of April and a high amount of secondary infection cycles were detected by the Goidanich algorithm during the fruit development and berry ripening stages. The best estimators of the P. viticola spore concentrations were the fungus spore levels during the previous day, the average temperature 5 days before and rainfall 2 days before. The regression equation obtained accounted for the 95.9% of the spore concentration variation. The combination of the Goidanich index and biological sensors provides a valuable tool to establish an accurate, modern, integrated downy mildew pest-management strategy.

Fungal Diseases in Two North-West Spain Vineyards: Relationship with Meteorological Conditions and Predictive Aerobiological Model

“…In our study area, the Erysiphe and Plasmopara infections were later than the Botrytis, between the end of flowering (S-6) and development of fruits (S-7). These results agree with findings by other authors [57][58][59]. Generally, powdery mildew requires relatively dry conditions and moderate temperatures, while downy mildew is greatly affected by wet conditions, either the presence of dew or rainfall [60].…”

A Weather-Driven Model for Predicting Infections of Grapevines by Sporangia of Plasmopara viticola

“…Concerning airborne P. viticola sporangia, the current study confirmed other reports that P. viticola sporangia are a common component of the airborne microflora of vineyards ( Diaz et al, 1998 ; Albelda et al, 2005 ; Fernandez-Gonzalez et al, 2009 ; Magyar et al, 2009 ; Fernández-González et al, 2011 , 2019 ; Martínez-Bracero et al, 2019 ; Rodríguez et al, 2020 ). This is highly relevant to DM management: while the inoculum for primary infection is available only following a rain, the secondary inoculum is always present when P. viticola is established in the vineyard.…”

“…The next model step consists of DM-free sites on which the sporangia deposit after being detached from sporangiophores on sporulating DM lesions and dispersed into the air ( Figure 1 ). Because P. viticola sporangia become airborne under a wide range of environmental conditions ( Caffi et al, 2013a ) and because they are normally present in the air of DM-affected vineyards ( Diaz et al, 1997 , 1998 ; Albelda et al, 2005 ; Fernandez-Gonzalez et al, 2009 ; Magyar et al, 2009 ; Fernández-González et al, 2011 , 2019 ; Martínez-Bracero et al, 2019 ; Rodríguez et al, 2020 ), the model assumes that whenever there are sporangia on DM lesions, sporangia may detach, disperse, and be deposited on the host surface, i.e., when D’ > 0; if D’ = 0, there are no viable sporangia, and the model run ends.…”

Fungal Phytopathogenic Spore First Assessment in an Olive Orchard of Northwestern Spain

“…Therefore, the identification and quantification of the spore load in the atmosphere as bioindicators of pathogen presence, and their relationship with the meteorological and geographical data allows us to prevent the frequency and severity of diseases early [58]. Several studies detected a high degree of association between the aerial conidia concentration and the lesion density of the plants one week later, which shows the relation of disease development with spore concentrations in the atmosphere of the crop during previous periods [59][60][61]. The learning of the different ecological processes behavior of phytopathogenic fungus in the atmosphere of the crop is very important in regions where the cultivated area tend to the increase before the pressure of disease could be high.…”