The presence of weaver ants can increase cashew nut yields by up to 150 per cent, say researchers
The ants, known by their Latin name ‘Oecophylla longinoda’, reportedly act as an effective natural foil to a range of insect pests; most notably the West African fruit fly, which has been known to cause considerable damage to cashew crops.
The claims followed a two-year Danish-funded study in Benin, during which cashew trees with weaver ants patrolling were found to produce between 78 and 151 per cent more harvestable nuts than those without.
“The presence of weaver ants patrolling the trees provides protection against pests,” biologist Jean-François Vayssières told SciDev. “They can have a direct impact by capturing insects as prey, through excretions that act as a repellent or simply by their physical presence.”
Vayssières, who heads a separate project aiming to control fruit fly numbers at the International Institute of Tropical Agriculture (IITA), added that his studies had shown the ants’ pheromones acted as a repellent to the pests.
Cashew nuts are an important crop throughout Africa, including in Benin, where they have overtaken cotton as the primary export.