Assessment of yield loss due to the millet head miner, Heliocheilus albipunctella (Lepidoptera: Noctuidae) using a damage rating scale and regression analysis in Niger
Linear equations for five pearl millet (Pennisetum glaucum) varieties were established for yield losses due to damage by the noctuid Heliocheilus albipunctella, using a panicle damage rating scale. A very high positive correlation (r0.90; P=0.001) was found between damage rating and percentage yield loss, and also between observed and predicted yield loss. The low percentage absolute deviation (% ad) and deviation ratios (dr) between observed and predicted yield loss demonstrated the reliability of the damage rating scale, and the established yield loss equations. In addition, the damage rating on farmers'' fields by farmers and a team of technicians showed that the method can be used for quick on-farm assessment of yield loss by extension agents and farmers. In four farmers'' fields, the estimated yield loss for the local variety (Sadore local) ranged from 11.7 to 41.9%. Implications of the use of the method for future crop loss assessment in pearl millet are presented and discussed