By Dr Mobolade D. Akinbuluma

The fall armyworm (FAW) is a global insect pest that feeds on > 350 plant species and causes major yield loses. The insect uses ‘pheromones’ as a primary means of sexual communication to locate and select mates. An important concept has revealed that the variation in the responses of FAW males to sex pheromone compounds released by females affects the detection, monitoring and management of the pest. Therefore, five synthetic pheromone compounds were tested on African (Benin, Kenyan and Nigerian) male insects and compared with American (Floridan) males, with the use of a gas-chromatograph coupled with electroantennogram detector (GC-EAD) which enabled responses to be measured from the antennae of the male insects.

According to Dr M. D. Akinbuluma, a Senior Lecturer in the Department of Crop Protection & Environmental Biology, University of Ibadan, Nigeria and Postdoctoral Researcher, Institute of Biodiversity and Ecosystem Dynamics at the University of Amsterdam (UvA), The Netherlands, with the correct type(s) and composition of the sex pheromone compounds from the African female insects, their male counterparts can be arrested and this will invariably lead to tackling the menace of the hungry worms in African fields. The academic, together with his colleagues at UvA, discovered that the pheromone compounds in the insects from America (the native range of the insect) differ from those of the African continent (the invasive range) and that the variations have significant implications in the pest control in the latter region. Regional differences were also discovered between the responses of the two identified male mitotypes to the female odour sources. Akinbuluma firmly recommends that effective pheromone-based strategies for monitoring and managing fall armyworm is needed for enhanced food security in the African region.

In yet another latest study, the academic and researcher hypothesized whether six different varieties (types) of maize plants, a major host to the invasive pests, could be used to enhance control of FAW. After conducting different experiments using with standard techniques, Akinbuluma narrowed on the cultivation of hybrid maize seeds like the DEKAIB and 30Y87 by farmers not only because FAW females are avoided laying eggs on them to enhance their growth and multiplication but also because the insects were not attracted to the maize varieties in a Y-tube olfactometer test using the odours from the plant. 

Trapping volatiles from maize plant varieties

He further stressed that the insects were attracted to certain chemicals (semio-chemicals) in some maize varieties than in others and that all hands must be on deck to identify them. Finally, he succinctly advocates multidisciplinary approach into studying the chemistry of maize varieties that will further help to identify clues to develop those with increased resistance against FAW attack, so that food (especially maize) may not be further hindered within the African continent.

The battle for Africa’s fields is far from over as the competitive struggle for survival with fall armyworm persists, but with new strategies in hand, victory is within reach, says Dr Akinbuluma.