PEST MANAGEMENT DECISION GUIDE: GREEN AND YELLOW LIST
Bacterial Blight on common Bean
Xanthomonas axonopodis. pv. phaseoli
- Plant resistant varieties e.g. new rose coco, miezi mbili and red kidney.
- Plant certified seed from certified dealers.
- Remove and burn crop debris.
- Plough deep and bury crop residues to enable breakdown of infected plant debris.
- Rotate with non leguminous crops e.g. maize, cabbages for 2 - 3 seasons.
- Ensure proper crop nutrition to keep plant vigour.
- Keep the field free of weeds and volunteer plants.
- Use furrow or drip irrigation to avoid spread of the disease when leaves are wet.
- Avoid field operations when the leaves are wet
- Disinfect plant implements when moving from one field to the other.
- Use proper spacing (50cm x 10cm) to ensure air circulation
- Intercrop beans with maize to prevent spread of the disease from one row to the other.
- Look for small angular water soaked reddish brown spots that enlarge and turn necrotic on leaves surrounded by a bright yellow halo.
- Look out for small water soaked lesions which become sunken and dark red-brown on pods.
- Check for yellow or brown spots on seeds near the hilum. Under severe infection, seeds appear shrivelled. A yellowish bacterial ooze is released from the lesions under humid conditions.
- Remove and burn infected plants.
- Practise soil solarisation to kill bacterial inoculum in the soil. Cover your soil with a transparent plastic paper for 4 weeks during hot seasons to kill the bacteria in the soil.
- Avoid introducing bacterial infections to farms because they are difficult to eradicate completely from the soil once introduced.
- WHO class II pesticides might not be allowed in local IPM schemes.
Spray copper oxychloride WG (eg Cupro Caffaro Micro 37.5 at a rate of 50gm/20lts water and Isacop 50WP at a rate of 50-60g/20litres of water). Spray early in the morning or late in the evening to minimize pesticide drift. Avoid spraying two hours before rainfall.
WHO class II (Moderately hazardous). Irritant to the eyes. Re-entry: when the chemical spray dries up
CREATED/UPDATED: August 2014
PRODUCED BY: Plantwise
©CAB International. Published under a CC-BY-SA 4.0 licence.