Push-Pull protects against fall armyworm


The fall armyworm, a pest native to tropical and subtropical America, has recently invaded Africa, causing substantial damage to maize and other crops. Scientists of our partner organisationicipe (International Centre of Insect Physiology and Ecology) evaluated functionality of a companion cropping system, ‘climate-adapted push-pull’, developed for control of stemborers in drier agro-ecologies, as an added tool for the management of fall armyworm.

The Push-Pull method, supported and promoted by Biovision, comprises two important factors: Between maize and sorghum desmodium is planted, which repels the stemborer – Push – and also fertilises the soil and, as it covers the ground, it helps keep the water in the soil. Around the fields, napiergras or brachiaria is planted, which attracts the stemborer – Pull. The larvae of the stemborer then perish in the sticky leaves of those two plants.

250 farmers who had adopted the technology in drier areas of Kenya, Uganda and Tanzania were randomly selected for the study during the long rainy season from March to August of 2017. Each farmer had a set of two plots, a climate-adapted Push–Pull and a maize monocrop. Data were collected in each plot on the number of fall armyworm larvae on maize, percentage of maize plants damaged by the larvae and maize grain yields. Similarly, farmers' perceptions of the impact of the technology on the pest were assessed using a semi-structured questionnaire.

Reductions of 82.7% in average number of larvae per plant and 86.7% in plant damage per plot were observed in climate-adapted push-pull compared to maize monocrop plots. Similarly, maize grain yields were significantly higher in the climate-adapted push-pull plots. (see figure)

Farmers rated the technology significantly superior in reducing fall armyworm infestation and plant damage rates. These results demonstrate that the technology is effective in controlling fall armyworm with concomitant maize grain yield increases, and represent the first documentation of a technology that can be immediately deployed for management of the pest in East Africa and beyond.

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