PEST MANAGEMENT DECISION GUIDE: GREEN AND YELLOW LIST
Whiteflies on tomato
- Remove tomato residues and volunteer tomatoes and bury or burn.
- Plant tomatoes 0.5-2 feet apart with at least 3 feet between rows.
- Use a shade net (size 400 µm)/tunnel for 3-5 weeks while in nursery to prevent attack by white flies.
- Transplant shortly after or during the rainy season.
- Use white/black inert plastic mulch 10-20 days after transplanting which attracts and kills whiteflies.
- Conserve natural enemies (wasps, ladybirds) by mulching or leaving a natural hedge of flowering plants (e.g. Tithonia, Lantana) along the edges to offer them refuge.
- Plant repellent crops such as coriander or Mexican marigold after 3-4 rows of tomato to repel the whiteflies.
- Keep the field weed-free throughout the cropping season since weeds act as alternate hosts and can harbour whitefly-transmitted viruses.
- Adult: a sucking insect, about 1 mm long. The body and wings are covered in a powdery, white to slightly yellowish in colour.
- Larva: yellow-white scales, 0.3-0.6 mm long on the underside of leaves.
- Puparium: flat, irregular, oval shape, 0.7 mm long.
- Eggs: whitish and pear-shaped, 0.2 mm long.
- After transplanting monitor weekly until harvest.
- Search for leaves with whitefly groups (they are mainly on underside of leaves). They will fly and resettle when you shake plants.
- Yellowing, curling, crumpling of leaves occurs at heavy infestation.
- Action threshold level is 10-20 plants with symptoms and/or at least 20 whiteflies on at least 10-20 plants/acre.
- Use yellow sticky traps at about 1 per 5 plants to capture and kill adult moths.
- Spray Beauveria bassiana products during the early morning or late afternoon (check product labels for dosage) to kill larvae and adults. Re-apply if needed after 21 to 28 days.
- Introduce natural enemies such as predatory mites or parasitic wasps to attack eggs and reduce the pest population.
- Use liquid soap spray at rate of 3 table spoons per litre of water.
- When using a pesticide or botanical, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, pre-harvest interval, max number of sprays, restricted re-entry interval. Do not empty into drains and water sources.
- Do not use chemicals with the same mode of action year after year as this can lead to resistance, always consult the most recent list of registered pesticides of MODA, Ghana.
Spray Azadirachtin 0.03% (50 ml/20L water) 15 days after transplant.
Not classified by WHO, but considered unlikely to present acute hazard in normal use. PHI 3 days, REI 1 day. Toxic to fish.
CREATED/UPDATED: July 2017
PRODUCED BY: Plantwise
©CAB International. Published under a CC-BY-SA 4.0 licence.