System Article
Gray Mold
Gray mold, or botrytis blight, Botrytis cinerea, causes a greater loss of strawberry flowers and fruit than any other disease. It is found on green as well as ripening and harvested fruit.
#Strawberries
System Article
Gray mold, or botrytis blight, Botrytis cinerea, causes a greater loss of strawberry flowers and fruit than any other disease. It is found on green as well as ripening and harvested fruit.
#Strawberries
Overview Strawberry Gray Mold Disease is caused by the fungus Botrytis cinerea. It is a common and destructive disease in strawberry production that affects both the fruit and, in some cases, other parts of the plant. The disease is notorious for causing significant losses in yield and fruit quality, especially under conditions of high humidity and cool temperatures. Symptoms 1. Fruit Symptoms: o Gray Mold: The primary symptom is the appearance of grayish-brown, fuzzy mold on the fruit. This mold consists of a dense mat of fungal mycelium and spore-producing structures. o Rotting: Infected fruit becomes soft and mushy. The mold typically begins on the fruit's surface and spreads rapidly. o Premature Decay: Fruit may begin to decay and shrivel before reaching full maturity. 2. Blossom Symptoms: o Blossom Blight: The disease can also affect strawberry flowers, causing them to become water-soaked, brown, and mushy. Infected blossoms fail to develop into fruit. 3. Leaf Symptoms: o Leaf Spots: Although less common, Botrytis cinerea can cause small, irregularly shaped spots on leaves. These spots are typically grayish with a brown border.
Disease Cycle 1. Inoculum Source: The fungus Botrytis cinerea overwinters in plant debris, soil, and on infected plant parts. It also produces a large number of airborne spores that can spread the disease. 2. Spore Release: During wet or humid conditions, the fungus releases conidia (asexual spores) that are dispersed by wind, rain, or insects. 3. Infection: Spores land on ripe or nearly ripe strawberries and infect them through natural openings or wounds. High humidity and prolonged wet conditions favor spore germination and infection. 4. Disease Development: Once infected, the fruit becomes covered in gray mold. The fungus can then spread to other fruit and plant parts, perpetuating the disease cycle. 5. Spore Dissemination: As the infected tissues decay, they release more spores into the environment, further spreading the disease to healthy plants. Favorable Conditions • High Humidity: The disease thrives in high humidity and conditions of prolonged leaf wetness. • Cool Temperatures: Botrytis cinerea prefers cooler temperatures, typically between 55°F and 75°F (13°C to 24°C). • Dense Planting: Crowded plantings and poor air circulation increase humidity around the plants, creating ideal conditions for the disease.
Management Strategies 1. Cultural Practices: o Proper Spacing: Space plants adequately to improve air circulation and reduce humidity around the fruit. o Pruning: Remove and destroy infected fruit and plant debris to reduce the inoculum source. o Avoid Overhead Irrigation: Use drip irrigation to minimize moisture on the fruit and reduce the risk of infection. o Crop Rotation: Rotate strawberries with non-host crops to minimize fungal buildup in the soil. 2. Sanitation: o Remove Debris: Regularly clean up plant debris and fallen fruit to reduce sources of fungal spores. o Disinfect Tools: Use disinfected tools to prevent the spread of the disease from one plant to another. 3. Fungicide Applications: o Preventive Sprays: Apply fungicides as a preventative measure, particularly during flowering and fruit development. Common fungicides include those with active ingredients such as chlorothalonil, boscalid, or pyraclostrobin. o Rotate Fungicides: Rotate between different classes of fungicides to reduce the risk of resistance development. 4. Resistant Varieties: o Variety Selection: Some strawberry varieties have partial resistance to Botrytis. Consult local extension services or nurseries for information on resistant varieties. 5. Monitoring and Timing: o Regular Inspection: Regularly inspect plants for early signs of infection and take action promptly to prevent the spread of the disease. Conclusion Strawberry Gray Mold Disease, caused by Botrytis cinerea, can have a significant impact on strawberry crops, leading to reduced yields and fruit quality. By understanding the disease cycle and implementing a combination of cultural, sanitation, and chemical control measures, growers can effectively manage and reduce the impact of this disease. Regular monitoring and timely interventions are key to protecting strawberry crops and ensuring a healthy harvest.
