Strawberry affliction by Phomopsis Leaf Blight and Fruit Rot
In Ohio, the economic impact of Phomopsis leaf blight in strawberry production may be relatively minor, but the incidence of the disease has been on the rise. This article aims to provide a comprehensive guide on cultural practices and fungicide options for managing the disease in the state.
Site Selection
To promote a healthy strawberry crop, it's essential to choose a site with excellent soil drainage, air circulation, and full sun. This encourages faster drying of plant parts, which is crucial in minimising the favourable conditions for Phomopsis leaf blight.
Symptoms and Disease Development
The symptoms of Phomopsis leaf blight on strawberry leaves start as circular spots, similar to those caused by leaf spot disease. However, young lesions have a reddish halo. Unlike some diseases, temperature has less effect on disease development than the duration of wetness.
Impact on Strawberry Plants
Phomopsis leaf blight can weaken strawberry plants through the destruction of older foliage, potentially leading to reduced yields the following year. If lesions develop prior to harvest, they can produce pycnidia which release conidia to infect the fruit, causing Phomopsis fruit rot, also known as soft rot, especially in warmer climates.
Cultural Practices
Effective management of Phomopsis leaf blight includes good sanitation, crop rotation, improved air circulation, and irrigation management. Removing and destroying infected plant debris and mummified fruit reduces the inoculum source. Avoiding planting strawberries in the same soil repeatedly helps minimise pathogen build-up. Improved air circulation can be achieved by spacing plants adequately and managing weeds. Using drip irrigation instead of overhead sprinklers keeps foliage dry and reduces leaf wetness periods that favour disease development. The use of disease-free planting material is also crucial, as varieties differ in susceptibility to leaf blight.
Fungicide Options
Typically, fungicides effective against Phomopsis include those containing chlorothalonil, captan, fenhexamid, or thiophanate-methyl. These fungicides are often recommended as part of a spray program timed to protect young leaves and developing fruit. In Ohio, fungicide programs are usually integrated with cultural practices and applied preventively during conditions favourable for disease development (warm, humid weather). For specific pesticide recommendations and timings, consulting local extension publications such as from Ohio State University Extension or the Midwest Small Fruit Pest Management Guide is important, as these resources provide regionally tailored guidance and resistance management.
Recent Research
Recent research mentions the use of bimetallic nanoparticles in reducing certain strawberry fungal diseases, but these are still experimental and not standard recommendations for Phomopsis management.
Conclusion
For Ohio strawberry growers, combining good sanitation and cultural practices with regionally approved fungicides in a coordinated spray schedule is the recommended approach to manage Phomopsis leaf blight and fruit rot effectively. For precise fungicide labels and timings, refer to Ohio State University Extension publications or local plant disease diagnostic labs.
The integration of science-backed pest management strategies into the cultivation of strawberries can contribute significantly to health-and-wellness by mitigating the impact of soil-borne pathogens such as Phomopsis leaf blight. With the correct site selection, cultural practices, and awareness of fungicide options, growers in Ohio can implement a comprehensive approach to soil health and pest management in their strawberry production.
