Push-Pull — Companion Planting That Beats Two Pests at Once

Maize and sorghum farmers across East Africa face two quiet thieves: stemborer caterpillars that bore into the stalks, and Striga, a purple-flowered weed that latches onto the roots and can take most of a harvest before anyone sees it. Push-Pull fights both with plants instead of chemicals. You “push” the pests away by planting Desmodium between the rows, and “pull” them out of the field with a border of Napier or Brachiaria grass that traps the egg-laying moths.

At a glance Origin: East Africa, developed at icipe (the International Centre of Insect Physiology and Ecology), Kenya · Maturity: Scaled · Effort: no chemical cost, but real labor to establish and manage the companion plants · Licence: open, owned by no one.

How it works. Desmodium, a low legume grown between the cereal rows, gives off smells stemborer moths avoid — the “push” — and its roots release natural compounds that make Striga seeds sprout and then die before they can attach, so the weed’s seed bank in the soil falls year on year. A border of Napier or Brachiaria grass around the plot is the “pull”: moths lay their eggs on it instead of the maize. As a bonus, Desmodium fixes nitrogen and makes good fodder, and the grass feeds livestock too.

What to expect — and what it does NOT do. Where Striga is severe, farmers have seen maize yields rise sharply once the system is established — icipe reports maize climbing from around 1 to about 3.5 tonnes a hectare — with far less pest damage and better soil over time. But it is not plant-it-and-leave: establishing Desmodium takes work and patience, and the single biggest obstacle is getting Desmodium seed, which has been scarce and is the main reason the method hasn’t spread faster. It suits mixed cereal-and-livestock smallholdings in the right rainfall; it is not a fit where there is no use for the extra fodder or where the companion seed simply can’t be obtained.

Who made it. Developed at icipe in Kenya, with Prof. Zeyaur Khan long associated with the work, together with the farming communities who refined it in their own fields — not one inventor.

Used it? Tell us how it went — what you planted, whether Striga and stemborer really fell, whether you could get Desmodium seed, what you’d change, and roughly where and when. We want the honest result, including what didn’t work. Your contact details stay private; we read and check every report before anything is published, and we’ll never publish a detail you’ve asked us to keep private.

Sources: icipe’s Push-Pull programme (push-pull.net) and its free Climate-Smart Push-Pull field manual (technologytransfer.icipe.org).