7 research outputs found
Ecological management of cereal stemborers in African smallholder agriculture through behavioural manipulation
1. Africa faces serious challenges in feeding its rapidly growing human
population owing to the poor productivity of maize and sorghum, the most important
staple crops formillions of smallholder farmers in the continent,with yields being among
the lowest in the world.
2. A complex of lepidopterous stemborers attack cereals in Africa. However, their
effective control is difficult, largely as a result of the cryptic and nocturnal habits of
moths, and protection provided by host stem for immature pest stages.Moreover, current
control measures are uneconomical and impractical for resource-poor farmers.
3. An ecological approach, based on companion planting, known as ‘push–pull’,
provides effective management of these pests, and involves combined use of inter- and
trap cropping systems where stemborers are attracted and trapped on trap plants with
added economic value (‘pull’), and are driven away from the cereal crop by antagonistic
intercrops (‘push’).
4. Novel defence strategies inducible by stemborer oviposition have recently been
discovered, leading to the attraction of egg and larval parasitoids, in locally adapted
maize lines but not in elite hybrids. We also established that landscape complexity did
not improve the ecosystem service of biological control, but rather provided a disservice
by acting as a ‘source’ of stemborer pests colonising the crop.
5. Here we review and provide new data on the direct and indirect effects of the
push–pull approach on stemborers and their natural enemies, including the mechanisms
involved, and highlight opportunities for exploiting intrinsic plant defences and natural
ecosystem services in pest management in smallholder farming systems in Africa