PEST MANAGEMENT DECISION GUIDE: GREEN LIST
Serpentine leaf miner on beans
- Use tolerant crop varieties if available
- Where possible, cover small plants with transparent plastic (such as polytunnels) to prevent insects from laying eggs
- Weed out leguminous plants which can be alternative hosts such as sweet clover, Lathyrus, and many others.
- Plant maize around beans because maize acts as a barrier against the leaf miners
- Rotate beans with cereals, and not with legumes, tomatoes, garlic, onions, groundnut, rape, melon or cucumber.
- Tomato is a host plant for L. trifolii
- Monitor weekly at all growth stages of crop
- Look for tiny thread-like tunnels (mines) on the upper leaf sides
- Look for larvae inside tunnels or on the upper side of leaves (tiny legless maggots with no separate head, whitish, transparent and later yellow-orange)
- Threshold: At 8 to 12 infected plants (with 5-6 infected leaves) per 100 plants, consider green direct control action
- If, after green direct control, leaf miner damage still increases up to 20 to 30 infected plants per 100 plants, then consider chemical action
- Use yellow sticky traps to assess the presence of L. trifolii
- Hand pick heavily infested leaves with many leaf miner tunnels, and destroy them by crushing or burying them, or feeding them to cattle
- Spray neem extract against larvae onto leaves in the early morning or late evening. Add a sticker such as liquid soap to the neem water mix. Reach good leaf coverage. Neem slightly enters the leaves and reaches some of the larvae inside the tunnel
- If possible, cover soil under infested plants with plastic sheets to prevent larvae from reaching the ground and pupating
- Use yellow sticky traps to reduce numbers of L. trifolii
- Parasitoids, and to a lesser extent to nematodes, bacteria and fungi, are used for biological control of leafminers
CREATED/UPDATED: May 2017
PRODUCED BY: Plantwise
©CAB International. Published under a CC-BY-SA 4.0 licence.