Ch 5: Managing FAW with Push Pull

Push-pull technology

Push-pull is a habitat management strategy developed and implemented to manage pests such as stem borers, striga weed and address soil degradation, which are major constraints in maize production in Africa. The technology entails using a repellent intercrop (Desmodium as a “push”) and an attractive trap plant (Napier/Brachiaria grass as a “pull”).

The Napier grass planted around the maize farm:

•  attracts stemborers and FAW to lay eggs on it;
• but it does not allow larvae to develop on it due to poor nutrition; so very few larvae survive. At the same time, Desmodium, planted as an intercrop:
•  emits volatiles that repels stemborers or FAW, and
•  secretes root exudates that induces premature germination of striga seeds and kills the germinating striga; so this depletes seed banks of striga in maize farms over time;
•  covers the ground surface between maize, thus smothering weeds
•  enriches the soil with nitrogen, preserves soil moisture and protects the soil from erosion

The Desmodium and Napier/Brachiaria grass grown in Push-pull farms also:

•  provide valuable biomass as fodder for livestock, which can translate into increases in dairy products like milk.

“Push-pull climate smart” (combination of Desmodium Greenleaf and Bracharia cv Mulato II):

•  is designed for dry and hot conditions to address the challenges posed by climate change
•  Brachiaria grass grows fast with less water, and has been found to tolerate dry conditions better than Napier grass.

Push–pull is an effective and efficient low-cost technology as it addresses some major constraints faced by smallholder farmers. The multiple benefits of this technology can result in an overall and significant improvement of farmer’s food security and livelihoods.

Observations on FAW (S. frugiperda) by at least 250 farmers who had adopted the climate-smart Push-pull technology in drier areas of Kenya, Uganda and Tanzania indicated reduction of FAW larvae per plant and subsequent reduction in plant damage. Further surveys on climate-smart Push-pull and monocropped maize farms indicated 82.7 percent reduction in average number of larvae per plant and 86.7 percent reduction in plant damage per plot in climate-adapted push-pull compared to maize monocrop plots.

Hence, Push-pull technology appears effective in controlling FAW, with associated maize grain yield increases under the conditions tested. This technology could be immediately deployed for management of the pest in East Africa and in areas with similar conditions. Further testing in other agroecological zones is needed (Midega et al. 2018).

The push-pull technology is a specific application illustrating the general principle of the role of plant diversity on insect populations. There may be other plants (including crop species) that can be used to ‘push’ or ‘pull’ FAW and its natural enemies.