The system also promotes soil fertility.
Researchers have found intercropping maize with drought-resistant greenleaf desmodium and planting Brachiaria grass on the farm’s edge helps curb fall armyworms.
Desmodium and Brachiaria grass are high quality animal fodder plants.
The leguminous greenleaf desmodium becomes repellent, emitting a blend of compounds that help push armyworms away from maize while Brachiaria Mulato II grass around field edge produces chemicals attractive to the pests.
The International Centre of Insect Physiology and Ecology (Icipe) said that the “push-pull” crop system also promotes soil fertility and hinders the striga weed from attaching roots of cereal crops.
Icipe together with Rothamsted Research of Britain studied 250 maize farms that have adopted the push-pull method in western Kenya, eastern Uganda and northern Tanzania and found that the climate-adapted push-pull technology controls fall armyworm in smallholder farming systems in East Africa.
The method was initially developed for control of cereal stem borers and striga weed.
The scientists studied Kenya’s Bungoma, Busia, Siaya, Vihiga, Migori and Homa Bay sub Counties, Tarime district in Tanzania, Uganda’s Iganga, Bugiri ,Tororo and Bukedea districts.
Data on number of fall armyworm larvae on maize, percentage of maize plants damaged by larvae and grain yields was collected. Each farmer had a set of two plots, a climate-adapted push–pull and a maize monocrop.
There was 82.7 per cent reduction in number of fall armyworm larvae per plant and 86.7 per cent drop in plant damage per plot with push-pull systems. Grain yields were significantly higher, 2.7 times in systems plots.
“The farmers in the push-pull project reported that their fields were free of fall armyworm infestation while neighbouring monocrop plots were being ravaged by the pest,” said ICIPE’s Pull-Push Leader Prof Zeyaur Khan.