Cabbage aphids are small insects, they are also called "Inda" in Kinyarwanda. Their feeding can change the shape of leaves, especially of old plants and also cause leaf curl. They appear in groups and are of different colours (including greenish, grey and black). There are several species of aphids that damage cabbages and similar crops.
The aphids feed by sucking juices from the cabbage plant. This feeding may spread diseases from plant to plant. The diseases are the main cause of damage. Cabbage aphids live on the underside of leaves, in the centre of cabbage head and prefer young leaves. Groups of aphids in the heads of cabbage are not easy to control. Cool and dry weather favor the growth of aphids. Large number of aphids can kill the plant.
- Inspect your garden for aphids regularly (3 times per week)
- Destroy and burry infested plants and plant materials; this will reduce the number of aphids in the field.
- Apply a spray of soap 1-2 times per day early in the morning or late in the afternoon. The spray is made by putting 5-8g of soap (used for wash dishes) into one liter of water.
- If all the natural options fail, try applying a pyrethroid insecticide (e.g. cypermethrin 5%) in one season and then Profenofos40%+ Cypermethrin4%1ml/1l (Roket ,Jaket, Profex Super) the following season. Use the recommended concentrations according to the labels.
Warning: Extensive use of pyrethroids can reduce their effectiveness on aphids, and also kill friendly insects. You must use appropriate safety equipment when applying insecticides, especially something to cover the mouth and nose, and protect the eyes with glasses.
When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.