Push-pull technology is a ecological method of pest-control. It keeps pests away from crops in two ways: using one plant near the crop to repel ('push') pests away from it, and using a second plant beyond the field of crops to pull the pests away.
Maize farmers in Kenya have successfully used this to combat the stemborer larvae that attack their plants. They plant desmodium between rows of maize and Napier grass around the field. The desmodium repels the stemborers from the maize, and the Napier grass attracts them.