Botrytis Management in Strawberry & Grape: Strategies & Tech

Pathogen Dynamics and Infection Cycle in High-Value Crops

Botrytis cinerea, commonly known as gray mold, represents one of the most destructive fungal diseases for high-value crops like strawberries and grapes in Latin America’s viticultural and fruit-growing regions. Its impact results in significant yield losses and post-harvest quality issues, directly affecting producer profitability. Understanding this pathogen’s dynamics and implementing integrated management strategies is essential for safeguarding production and ensuring the sustainability of agricultural systems.

The fungus Botrytis cinerea is a necrotrophic pathogen capable of infecting a wide range of plant tissues, from flowers and young fruits to leaves and stems. Its life cycle is favored by conditions of high relative humidity (above 90%) and moderate temperatures (between 15°C and 25°C), factors prevalent in many strawberry and grape-producing areas, especially during flowering and veraison. Initial infection often occurs in the flowers, remaining latent until the fruit reaches maturity, at which point the fungus becomes active, causing the characteristic soft, grayish rot. In grapes, the rot can manifest as “noble rot” under very specific conditions, but in most cases, it is a devastating disease. Spores, conidia, are dispersed mainly by wind and rain, rapidly colonizing new areas of the crop.

Prevention is the cornerstone of botrytis management. Implementing appropriate cultural practices drastically reduces disease pressure. Optimal ventilation within the plant canopy is crucial; this is achieved through strategic pruning to remove excessive foliage and ensure good air circulation, thereby lowering ambient humidity around the fruits. In strawberry cultivation, the use of plastic or straw mulches minimizes contact between fruits and moist soil, a source of inoculum. For grapes, managing vine vigor and defoliating the cluster zone improves solar exposure and aeration [1]. Selecting cultivars with greater genetic resistance is an increasingly relevant long-term strategy. For example, new grape varieties with thicker skins or less compact clusters are being developed, which reduces susceptibility to infection. Likewise, efficient irrigation, preferably drip irrigation, avoids wetting foliage and clusters, unlike sprinkler irrigation which favors spore dispersal and moisture persistence [2].

Cultural Practices for Fungal Inoculum Reduction

The integration of biological and chemical control methods offers a robust approach. Biological control agents, such as specific strains of Trichoderma harzianum or Bacillus subtilis, compete with Botrytis cinerea for nutrients and space, or produce antifungal compounds. These microorganisms are applied preventively during key phenological stages, such as flowering [3]. Regarding chemical control, fungicide use must be rational and part of a rotation strategy. Alternating products with different modes of action prevents the development of resistance in the pathogen, a growing problem in many regions. Fungicides based on fludioxonil, cyprodinil, or fenhexamid are effective options, but their application should be guided by risk thresholds and weather forecasts. New fungicide molecules, with more favorable toxicological profiles and greater specificity, represent a significant advancement in reducing environmental impact. Furthermore, the application of products based on plant extracts or essential oils is gaining ground as an alternative to synthetic fungicides, in line with organic and sustainable production trends.

Constant monitoring is fundamental for timely decision-making. Regular inspection of crops allows for the detection of early disease symptoms and the assessment of environmental conditions. Currently, precision agriculture integrates technologies that facilitate this task. Real-time weather and leaf wetness sensors provide crucial data for predicting botrytis outbreaks. Predictive models based on advanced algorithms analyze this data and alert producers to high-risk periods, optimizing treatment application windows [4]. Drones equipped with multispectral cameras can identify areas of plant stress or incipient infection before they are visible to the human eye, enabling targeted interventions. Mobile applications and farm management platforms offer tools to record observations, track disease progression, and access personalized recommendations. These technological advancements not only improve control efficacy but also contribute to more efficient resource management and reduced input use.

Effective management of Botrytis cinerea in strawberries and grapes requires a holistic and adaptive vision. The combination of preventive cultural practices, strategic use of biological control agents and fungicides, along with the implementation of advanced monitoring technologies, forms a robust integrated strategy. Adopting these practices not only protects current production but also fosters the resilience of agricultural systems against future challenges. Continuous innovation in plant genetics and precision agriculture tools will continue to provide new opportunities for more sustainable and productive management in our fields.

Biological Control Agents and Fungicide Rotation

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References:

[1] Instituto Nacional de Tecnología Agropecuaria (INTA). Integrated management of botrytis in grapevines. Available at: https://inta.gob.ar/documentos/manejo-integrado-de-botrytis-en-vid

Environmental Monitoring and Outbreak Prediction with Precision Agriculture

[2] Instituto Nacional de Tecnología Agropecuaria (INTA). Integrated disease management in strawberry cultivation. Available at: https://inta.gob.ar/documentos/manejo-integrado-de-enfermedades-en-el-cultivo-de-frutilla

[3] Infoagro. Biological control of Botrytis. Available at: https://www.infoagro.com/semillas_y_plantas/productos_biologicos/control_biologico_botrytis.asp

[4] Agrodigital. Sensors and Big Data: the key to more efficient agriculture. Available at: https://www.agrodigital.com/2023/07/20/sensores-y-big-data-la-clave-para-una-agricultura-mas-eficiente/