Greenleaf Desmodium

Push-pull grows maize with desmodium between the rows and napier grass as a border. Volatiles from the desmodium act on stemborer moths while the border grass draws them away from the crop, and the legume fixes nitrogen and covers the ground. It was developed in western Kenya and is used by large numbers of smallholders across East Africa.

Fertilizer rates, timing, and forms should follow local soil tests and regional guidance. AgricultureID does not publish universal fertilizer recommendations.

Intercropping with Desmodium species reduces infestation of maize by the parasitic witchweed Striga hermonthica dramatically, and the effect is far larger than shading or added nitrogen alone would explain. Root exudates that interfere with the parasite's germination and attachment have been described as the mechanism, alongside the soil-fertility and shading effects. It is an in-field weed-control effect from a companion crop rather than from a product.

Management combines resistant varieties, rotation, monitoring, and — where justified — locally authorized control products applied according to their labels.

The published account of how desmodium acts on stemborers has been revised more than once — including work arguing that the intercrop intercepts and kills larvae rather than repelling adult moths. AgricultureID records that the effect is well documented in the field and that the mechanism is an active research question, rather than asserting one explanation.

Greenleaf is a productive, palatable perennial legume for grass-legume pasture and for cut-and-carry, and it fixes nitrogen well. In push-pull systems the cut desmodium feeds stalled dairy animals, which is a large part of why the system is adopted: it produces fodder on land that is still growing maize.

The seed is small and expensive, seedlings are slow, and a desmodium intercrop takes time to cover before it does anything useful. Establishment cost and seed availability, not agronomic performance, are the reasons cited most often for non-adoption of push-pull, and vegetative propagation from stem cuttings is used to reduce them.

The trailing stems root where they touch moist soil, so an established stand thickens and persists and can be propagated by cuttings. That habit also makes it competitive with the crop if it is not cut back, so managing the intercrop is part of managing the maize.

Greenleaf persists under partial shade and under grazing better than many tropical legumes, which suits it to plantation understoreys and to mixed swards where a more erect legume would be removed.

Desmodium uncinatum, silverleaf, is used in the same systems and is not the same plant; the two differ in adaptation and in seed cost, and published push-pull results refer to specific species. Recommendations naming only "desmodium" must be resolved to a species.

Greenleaf needs reasonable moisture and does not tolerate a long dry season as well as stylo does, and it is grown in the wetter tropical highlands rather than in the seasonally dry savanna. That, rather than any preference, is what bounds the geography of the systems built on it.

Soil suitability should be assessed with local soil survey information and, where available, field testing.