System Article
Blossom blight is a rot disease of stone fruit and hosts include apricots, cherries, nectarines, peaches, plums and almonds. Apples and pears can also be affected by blossom blight, although economic damage is rarely seen.
#Strawberries
Overview Strawberry Blossom Blight, also known as Botrytis Blossom Blight or Botrytis Fruit Rot, is a fungal disease caused by the pathogen Botrytis cinerea. This disease primarily affects the blossoms of strawberry plants, leading to poor fruit development and significant yield losses. It can also impact the fruit itself if left unmanaged. Symptoms 1. Blossom Symptoms: o Initial Signs: The first symptoms of Blossom Blight appear as water-soaked, grayish- brown lesions on the strawberry flowers. These lesions can spread rapidly. o Blossom Collapse: Affected flowers may become wilted, darkened, and eventually collapse. The flowers fail to develop into fruit, leading to reduced yields. o Gray Mold: In advanced stages, the lesions are covered with a grayish, fuzzy mold, which consists of fungal spores. This mold is often most visible under damp conditions. 2. Fruit Symptoms: o Rotting: If the infection progresses, it can affect the developing fruit. Infected fruit will show gray, fuzzy mold and become soft and decayed. o Premature Ripening: Fruits may ripen prematurely and develop a shriveled appearance. 3. Leaf Symptoms: o Although less common, the disease can also cause small, irregularly shaped lesions on the leaves, particularly under high humidity conditions.
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 strawberry blossoms 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 flowers become covered in gray mold. The fungus can then spread to other flowers and developing fruit, 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 can 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 flowers. o Pruning: Remove and destroy infected flowers and plant debris to reduce the inoculum source. o Avoid Overhead Irrigation: Use drip irrigation to minimize moisture on the flowers 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. 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 Blossom Blight, caused by Botrytis cinerea, can cause significant damage to strawberry crops if not managed effectively. Understanding the disease cycle, recognizing symptoms, and implementing a combination of cultural, sanitation, and chemical control measures can help manage and prevent the spread of this fungal disease. By maintaining good practices and monitoring plants regularly, growers can protect their strawberry crops and ensure a healthy, bountiful harvest.
