Controlling Spur Blight in Berry Crops: Effective Strategies

Spur blight is a common fungal disease that affects berry crops such as raspberries and blackberries. It can lead to significant yield losses if not managed properly. In this article, we will discuss effective strategies for controlling spur blight in berry crops.

Understanding Spur Blight

Spur blight is caused by the fungus Didymella applanata. It typically infects young, succulent shoots and leaves, but can also infect fruit and older wood. The disease overwinters on infected plant debris and can spread through splashing rain or irrigation water, as well as from contaminated tools or equipment.

The symptoms of spur blight include small, dark spots on the leaves and stems, which enlarge and develop into sunken lesions. Infected leaves may also curl and become distorted. Fruit can also become infected, resulting in rotting and discoloration.

Cultural Practices for Spur Blight Control

Good cultural practices are essential for effective spur blight control. These include:

• Sanitation: Remove and destroy all infected plant debris, particularly after harvest. This includes any pruned material, old fruiting canes, and fallen fruit.
• Plant spacing: Proper plant spacing promotes good air circulation and reduces humidity levels, which can help prevent fungal growth.
• Irrigation: Avoid overhead irrigation, which can promote fungal growth. Instead, use drip irrigation or other methods that apply water directly to the soil.
• Fertilization: Apply fertilizer according to soil test results to promote healthy plant growth. Over-fertilization can lead to excessive vegetative growth, which can make plants more susceptible to fungal diseases like spur blight.
• Pruning: Prune plants regularly to remove dead or diseased wood, which can harbor fungal spores. After pruning, disinfect tools with a solution of 70% ethanol or 10% bleach.

Chemical Control Options

In addition to cultural practices, chemical control options are available for managing spur blight in berry crops. These include:

• Fungicides: Several fungicides are available for controlling spur blight, including captan, pyraclostrobin, and boscalid. Fungicides should be applied preventatively, starting in early spring when new growth appears. Follow label directions carefully and rotate among fungicides to reduce the risk of resistance.
• Bactericides: Some growers have reported success using copper-based bactericides for spur blight control. However, these products can be phytotoxic in some situations and should be used with caution.

Integrated Pest Management (IPM) Approach

Integrated pest management (IPM) is a holistic approach to pest control that combines cultural, biological, and chemical control methods. By using multiple tactics, IPM can help reduce dependence on any one method and minimize negative impacts on the environment.

Some IPM tactics for preventing and managing spur blight in berry crops include:

• Using disease-resistant cultivars
• Monitoring plants regularly for signs of disease
• Encouraging beneficial insects and other natural enemies of pests
• Using cultural practices to reduce disease pressure
• Using chemicals only as a last resort, and selecting products with low environmental impact

Raspberries infected with spur blight

Spur blight can be a serious problem for berry crop growers, but effective control strategies are available. By using good cultural practices, selecting resistant cultivars, and using chemical controls as necessary, growers can manage the disease and protect their yields.

: berry crop diseases, fungal infections in fruit crops, integrated pest management, agricultural practices