Identification and evaluation of the main risk periods of Botrytis cinerea infection on grapevine based on phenology, weather conditions and airborne conidia

Abstract

In the present study, a new method for a decision-support system for fungicide administration against the pathogen Botrytis cinerea in vineyards was developed based on Integrated Pest Management principles which identified an infection risk before the appearance of disease symptoms. The proposed method is based on the combination of (i) the phenological observations of the main susceptible stages to infection, (ii) the airborne spores monitoring, (iii) the forecasting of the suitable meteorological conditions for B. cinerea spore germination during the subsequent 4–6 days after the spore detection. Aerobiological, phenological and meteorological analyses were carried out using data from 2008 to 2015 in a vineyard of Northwestern Spain. Aerobiological spore data were obtained using a Lanzoni VPPS-2000 pollen-spore trap. Phenological observations were conducted on 22 plants of Treixadura cultivar following the BBCH (Biologische Bundesanstalt für Land und Forstwirtschaft, Bundessortenamt und CHemische Industrie) scale. The Magarey generic fungal model was applied for the identification of the main meteorological suitable periods for infection within the susceptible phenological stages of flowering and ripening of berries. Our results showed that climatic conditions favoured fungal development during flowering, although a higher incidence of B. cinerea infection risk-periods occurred during the prior-to-harvest stage of ripening of berries, the most susceptible phenological stage to B. cinerea infection obtained by the proposed methodology. This approach enables more precise targeting in pesticide spraying and reduction in pesticide application from 4–5 to 2–3 times per year at our commercial study. It also illustrates the real-world benefits of integrated disease risk modelling.

Botrytis cinerea Airborne Conidia and Their Germination Ability Assessed by Immunological Methods in a NW Spain Vineyard

“…We also found a strong correlation with relative humidity of the same day. This period of three to four days agrees with the indicated period by González-Fernández et al [16], who found a period between four to six days (depending on the phenological stage under propitious meteorological conditions) for conidia germination and plant infection since the detection of conidia presence.…”

“…According to this, we considered the flowering (S6-BBCH scale) as one of the most vulnerable grapevine phenological stages to B. cinerea infection. For the Ribeiro PDO vineyard area, González-Fernández et al [16] previously found that the highest airborne conidia levels are usually recorded near to the flowering phenological stage, thus indicating a higher activity and fungal development in this period. The bioclimatic indicator developed for this pathogen based on the Magarey model, gave as a result that the flowering stage is one of the most susceptible stages to infection [16].…”

“…Previous studies found a significant correlation between Botrytis squamosa aerial conidia at a given date and lesion density one week later in onion crops, both for managed and unmanaged sites, which shows the relation of disease development with spore concentrations during previous periods [15]. Furthermore, spores can be used for the evaluation of infection risk periods by the establishment of disease thresholds as a function of the airborne spore levels, distinguishing high-risk periods from low or moderate infection risk moments [16]. Airborne conidia are spread units designed for fungal propagation under favourable conditions that can indicate the disease potential.…”

Climate Change Impacts Assessment on Wine-Growing Bioclimatic Transition Areas

“…As a consequence, a reduction of the phytopathological fungal pressure in the vineyard could occur due to the less frequent propitious humidity conditions expected for infection and disease development, mainly in the Rias Baixas DO of the Eurosiberian area and the nearest transition zones. Therefore, a significant reduction in the number of phytochemical treatments will be expected, which will diminish the production costs and the risk of environmental pollution [106][107][108]. Malheiro et al [31] noted that the downy mildew contamination risk is low for BBLI values below 2500 and high for values exceeding 5100 [102].…”

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.…”