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Caterpillar Species are Maize Pests, Likely to Multiply with Climate Change

In East Africa, the caterpillars of two butterflies, Busseola fusca and Chilo partellus , represent a major threat for maize, the main food crop in the region. As recently borne out by the work of IRD researchers and their partners in Kenya, their distribution varies with altitude. Busseola fusca prefers mountain sides, whereas Chilo partellus predominate at low altitude; a new study has revealed this phenomenon. Temperatures play a role in several ways, leading to the conclusion that the populations of these two types of pest will grow in the coming years.

Thanks to the marked altitude steps of the East African mountains—genuine open-air laboratories— IRD scientists and their Kenyan partners from ICIPE, KEFRI and the University of Nairobi simulated the effects of climate change on crops. They recently revealed that the richness of silica of maize plants is lower at high altitude. This element, extracted from the soil, is essential for the rigidity of the leaves and stems of grass family crops such as maize, enabling them to defend against pests. However, at a low temperature, the plant does not absorb through the roots and incorporate silica as much. At high altitude, heavier rainfall is also a factor, meaning silica is leached and depleted from the soil.

Ollivier Girard/CIFOR

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