Can an anti-erosive Andropogon gayanus live hedge help regulate millet stem borer infestation in neighbouring millet fields?

Abstract

From 2008 to 2010, the effect of a wind erosion-alleviating practice, that is, planting of windbreaks of the perennial grass Andropogon gayanus Kunth on the populations of millet stem borer (MSB) Coniesta ignefusalis (Hampson) (Lepidoptera: Pyralidae) and the damage induced by this pest to pearl millet, was studied at Sadore (Niger). The extent of bored stems in the A. gayanus hedge bordering millet plots (23% on average) was significantly lower than in the millet plots (76% on average), with no MSB larva recovered, compared to an average of 2.2 larvae per stem in the millet plots over the three years. Andropogon grass was thus ruled out as a trap crop for MSB management. Under the conditions of this study, a pest regulation service by Andropogon grass hedges, synergistic with a potential wind erosion alleviating service, cannot be put forward.