How Can Botrytis Impact Crop Health and Yield?

One major outbreak of Botrytis can impact crop health and lead to substantial losses. The pathogen causes disease in crops by releasing enzymes and toxins that damage plant cells and break down plant tissue. This results in a range of visible symptoms, including soft rot, wilting, and blight. As the fungal disease progresses, it interferes with photosynthesis and the plant’s ability to absorb water and nutrients, ultimately leading to lower yields and poorer quality produce.

The disease is also notorious for causing spoilage in fresh fruit and vegetables. In certain crops, such as strawberries and grapes, the fungus can remain dormant in healthy-looking fruit for several weeks, only becoming active and causing visible rot as the fruit ripens during storage or transport.

Which Crops Are Most Affected by Botrytis?

Botrytis can infect over 200 plant species, but it most commonly targets these crops:

• Grapes: Botrytis bunch rot is one of the most important diseases to manage in vineyards. The risk of infection is high in late summer and early autumn as grapes begin to ripen, and can vary by grape variety.

• Berries: Strawberries, raspberries, blackberries, and other berryfruit are prone to Botrytis gray mold infection. This fungal disease often develops in spring and as the fruit ripens under wet or humid conditions. It can also cause post-harvest spoilage, particularly in strawberries.

• Tomatoes: in greenhouse crops like tomatoes, Botrytis can strike at any time of the year if humidity and ventilation are not managed properly.

• Kiwifruit: Botrytis is a major cause of stem-end rot in stored kiwifruit. Infection mainly occurs through harvest wounds and develops as the fruit is kept in cool storage.

Other crops affected by Botrytis include peppers (capsicum), cucumbers, orchard fruits such as apples, peaches, pears, and plums, as well as leafy greens like lettuce and spinach.

Can Botrytis Be Beneficial in Crop Production?

While Botrytis is usually a threat to crops, there’s a rare exception for winegrowers. Under specific climate conditions, Botrytis cinerea causes “noble rot” in white wine grapes – a controlled infection used to produce some of the world’s finest dessert wines.

Noble rot is triggered by humid, misty mornings, followed by warm and dry afternoons. This pattern allows the fungus to penetrate the grape skin without causing damaging rot. As moisture evaporates, the sugars, acids, and flavor compounds in the grapes become highly concentrated, causing them to dry out and shrivel up like raisins. The resulting grapes produce intensely sweet and complex wines with distinctive aromas after they are harvested.

Why Early Botrytis Detection Matters for Growers?

Catching Botrytis early can prevent small infections from turning into major crop losses. The disease spreads rapidly via spores carried by wind, rain, or physical contact, often infecting large areas of crops in a short amount of time. Yet most growers still rely on visual scouting alone to spot the rot, and by then the fungus has already been active for several days or weeks, making widespread crop damage often unavoidable.

That’s why early detection is vital. By identifying plant disease threats before they escalate, growers can take proactive steps to manage crop risk, such as applying fungicides as needed The result is smarter input use, fewer unnecessary treatments, and yield protection when it counts.

How Can Growers Use an Early Warning System to Monitor Botrytis Risk?

Early warning systems don’t just monitor and predict weather threats on the farm. They can also alert growers to the climate conditions conducive to plant diseases, such as Botrytis, days before symptoms appear in the field. Using climate and crop data from local sensors or satellites, these tools indicate when conditions are favorable for crop infection. With these proactive alerts, growers can respond faster and more effectively to prevent the disease from spreading.

How Can Growers Prevent Botrytis?

Prevention is the most effective strategy for managing crop diseases like Botrytis. By combining good cultural practices with proactive monitoring for early warning signs, growers can act before the disease takes hold. Here’s how:

1. Manage growing conditions: Monitoring relative humidity, VPD, temperature, and other climate data gives growers real-time insights to make timely adjustments to their growing environment, helping keep Botrytis outbreaks to a minimum.

2. Time irrigation wisely: Watering early in the day gives plants enough time to dry before nightfall, reducing the damp conditions that encourage Botrytis. Drip irrigation, which delivers water directly to the roots, is a better choice than overhead watering because it keeps the leaves dry.

3. Avoid overcrowding plants: Proper spacing promotes airflow between plants and reduces the chance of spores spreading from diseased crops to healthy ones due to overcrowding.

4. Remove infected material: Removing and promptly disposing of diseased plant material helps to limit the spread of gray mold. Avoid adding contaminated material to compost, as the spores can survive and then infect healthy plants.

5. Prune regularly: Regular pruning allows growers to inspect plants and remove any visible signs of infection. It’s also important to sanitize tools between each use to limit the potential for cross-contamination.

6. Improve air circulation: For protected cropping growers, installing fans or vents helps to facilitate better air exchange, which reduces moisture buildup and enhances the drying of plant surfaces.

7. Monitor and respond early: Tools like the GrowPilot app alert growers when there is a risk of Botrytis based on their farm’s climate. These alerts help growers make timely, informed plant disease management decisions, such as reducing humidity, adjusting irrigation, or applying preventative treatments.