Mwangi Mumero @PeopleDailyKe
Researchers at the International Centre for Insect Physiology and Ecology (Icipe) say the climate smart version of pull-push technology is helping control the emergent fall armyworm pest that has ravaged farmlands across Africa.
Originally developed for the control of stem borers, the key pests of cereal crops across most of Africa, and the parasitic Striga weeds, push-pull involves intercropping cereal crops with insect repellent legumes in the Desmodium genus, and planting an attractive forage plant such as Napier grass as a border around this intercrop.
The intercrop emits a blend of compounds that repel (‘push’) away stemborer moths, while the border plants emit semiochemicals that attract (‘pull’) the pests. “Over the past several months, information from push-pull farmers shows that their fields were free of fall armyworm infestation while neighbouring monocrop plots were being ravaged by the pest,” says Prof Zeyaur Khan, Push-Pull leader at Icipe.
“We evaluated the climate-adapted version of the technology as a potential management tool for fall armyworm in East Africa,” he says. The study revealed that fall armyworm infestation to be more than 80 per cent lower in plots where the climate-adapted Push-Pull is being used, with associated increases in grain yields, in comparison to monocrop plots.
Efforts to control the fall armyworm through conventional methods, such as use of insecticides is complicated by the fact that the adult stage of the pest is most active at night, and the infestation is only detected after damage has been caused to the crop.
The pest also has a diverse range of alternative host plants that enables its populations to persist and spread. “Moreover, fall armyworm has been shown to develop resistance to some insecticides, while the performance of such chemicals is also hindered by limited knowledge and purchasing power of farmers, resulting into use of low quality, and often harmful products,” says Dr Charles Midega,an Icipe scientist.
The fall armyworm is a destructive moth that causes devastating damage to almost 100 plant species, including sorghum, rice, wheat and sugarcane, as well as a variety of horticultural crops, thereby threatening food and nutritional security, trade, household incomes and overall economies.
Estimates from 12 African countries indicate the pest is causing annual maize losses of between eight and 21 million tonnes and monetary losses of up to $ 6.1 billion (Sh610 billion)