Bean rust is the result of an infestation by the fungus Uromyces appendiculatus, which targets the foliage, stems, and pods of bean plants. Failure to effectively manage this disease can result in the plant or its various components succumbing to extensive infection, ultimately leading to significant losses.
During the winter, the pathogen remains dormant in diseased plant remains and generates spores when favorable conditions arise. These spores are dispersed by the wind and infect healthy plants, initiating the disease.
Visible symptoms begin to manifest approximately 7-15 days after the initial infection, and the severity of yield loss is influenced by the timing of the infection, with earlier infections carrying a higher risk of reduced crop productivity.
INFECTION & SYMPTOMS
The infection can affect any aerial portion of the plant; however, symptoms are predominantly observed on the undersides of leaves.
Initially, the symptoms appear as small, raised white spots that eventually rupture, forming distinct circular reddish-brown spots. Some varieties may exhibit yellow rings around these spots. In severe cases, the extensive infection leads to leaf shedding or defoliation.
Infected pods display powdery pustules in a reddish-brown color, which are encircled by a yellow halo. As the infection advances, the pods become distorted in shape.
MANAGEMENT & CONTROL
Bean rust can be effectively managed and controlled using various approaches, including the utilization of chemical methods involving fungicides. Some examples of fungicides commonly used for this purpose are:
- BRADLEY 500SC: Recommended dosage is 10ml per 20 liters of solution.
- DOMAIN 250EC: Recommended dosage is 10ml per 20 liters of solution.
- DUCASSE 250EW: Recommended dosage is 20ml per 20 liters of solution.
- EXEMPO CURVE 250SC: Recommended dosage is 15ml per 20 liters of solution.
- EXPLORER 3SL: Recommended dosage is 10ml per 20 liters of solution.
- JUPITER 125SC: Recommended dosage is 15ml per 20 liters of solution.
- MILESTONE 250EC: Recommended dosage is 10ml per 20 liters of solution.
- MILLIONAIRE 690WDG: Recommended dosage is 40g per 20 liters of solution.
- PROVIDENCE 400WP: Recommended dosage is 50g per 20 liters of solution.
- RANSOM 600WP: Recommended dosage is 15g per 20 liters of solution.
- TOMAHAWK 250EC: Recommended dosage is 10ml per 20 liters of solution.
- TRINITY GOLD 425WP: Recommended dosage is 50g per 20 liters of solution.
- ABSOLUTE 375SC: Recommended dosage is 10ml per 20 liters of solution.
- COLONIZER 440WP: Recommended dosage is 50g per 20 liters of solution.
By employing these fungicides at the specified dosages, effective control and management of bean rust can be achieved.
Please take note of the following:
- When conducting spray applications, it is crucial to mix the fungicide with INTEGRA at a rate of 3ml per 20 liters. INTEGRA acts as a sticker, spreader, and penetrant, enhancing the effectiveness of the fungicidal treatment.
- Timely application of fungicides is of utmost importance to ensure optimal results in managing bean rust.
- It is recommended to alternate the use of different fungicides throughout the crop season. This practice helps prevent the pathogen from developing resistance to any specific chemical and ensures continued efficacy in disease control.
Other practices for managing bean rust include:
- Implementing crop rotation with nonhost crops.
- Choosing to plant resistant varieties of beans.
- Maintaining proper field sanitation practices.
- Effectively managing weeds in the field.
- Using certified seeds for planting.