PEST CONTROL
Clever Kenyan
pest control
! Push-pull planting ": Strategic intercropping and margin planting entices harmful bugs out of staple crops without pesticides
Smallholders struggling with insect infestations in their crops would do well to investigate the“ pushpull” form of pest management. The principle is based on the use of repellent plants which are planted within the crop field and the use of“ trap” plants which are planted in the veld margins around the crop field. A staple crop such as maize is vulnerable to stem borers. A secondary crop such as a Desmodium species is planted between the rows of the primary crop. A third crop such as Napier grass is planted on the edges of the land. So the approach relies on a combination of companion crops to be planted around and among the maize. The grasses are planted in the border around the maize fields where invading adult moths become attracted to chemicals emitted by the grasses themselves. Instead of landing on the maize plants, the insects head for what appears to be a tastier meal. These grasses provide the " pull " in the " push – pull " strategy. They also serve as a haven for the borers ' natural enemies. Napier grass has a particularly effective way of defending itself against the pests: once attacked by a borer larva, it secretes a sticky substance which physically traps the pest and limits its damage. The " push " in the scheme is provided by the intercropping plants that emit chemicals which repel stem borer moths and drive them away from the main crop. The best candidates discovered so far with the repellent properties are species of leguminous genus Desmodium. Desmodium is planted in between the rows of maize. Being a low-growing plant, it does not interfere with the crops ' growth and, furthermore, has the advantage of maintaining soil
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