PEST MANAGEMENT DECISION GUIDE: GREEN LIST
- Rotate planting of cotton with onion or maize. Be sure not to plant alternate hosts such as cucumber or tomato.
- Use of resistant varieties. Contact local extension officer of agro-dealer for locally available varieties.
- Avoid the use of broad spectrum insecticides to conserve natural pest species such as ladybird beetles, lacewings and parasitoids.
- Top the plants following boll opening to remove the upper leaves where aphids primarily feed. This reduces infestation on lower areas of the plant.
- Actively monitor crops for symptoms of infestation and aphid presence by eye and using a hand lens.
- Symptoms of aphid infestation include yellowing and curling of leaves. Stunted growth and distortion of plant stems.
- A characteristic feature of infestation is the presence of black sooty mould growing on the honeydew secretion from aphids.
- Adults are 2 mm long, with black heads and yellow/green bodied.
- Nymphs are pale yellow/green, roughly 1-1.5 mm long.
- Consider direct control actions if more than 5 aphids are found per plant when 20 are surveyed.
- Using a strong jet of water, wash aphids off the underside of leaves during early and low infestations roughly once a week.
- Prune heavily infested plant parts and destroy by burning.
- Control ant populations, as ants are associated with aphids due to their honeydew secretions and protect aphids from natural enemies. Use a band of sticky tape around the base of plants to trap ants.
- Use of neem extract (50 g neem seed cake per litre of water and 2 tablespoons of liquid soap). Spray no more than twice per season.
- Use of liquid soap solution (10 ml liquid soap, 85 g chopped/ground garlic, 1 litre of water and 50 ml of vegetable oil). Add 2 litres of water to the solution before use then spray.
CREATED/UPDATED: January 2019
PRODUCED BY: Plantwise
©CAB International. Published under a CC-BY-SA 4.0 licence.