Yield estimation and damage by Eoreuma loftini on sorghum genotypes and pearl millet in a warm-humid tropical climate

Abstract

Sorghum (Sorghum bicolor (L.) Moench) is one of the main forage crops for animal feed, although its productivity is often limited by pest pressure. One strategy to tackle this limitation is the development and adoption of pest-tolerant or resistant genotypes. The objective of this research was to evaluate sorghum genotypes and pearl millet (Cenchrus americanus (L.) Morrone) for Mexican rice borer (Eoreuma loftini) infestation, intensity of infestation, and forage yield. Larvae of E. loftini were detected in all evaluated sorghum genotypes and in pearl millet, with tunnels with horizontal and vertical direction along the stems. `Paloma', `Fortuna', `197-1-1', and `197-1' genotypes, along with pearl millet, showed the lowest infestation rates. Regarding infestation intensity or damage, `Proconsul' and `Gobernador' genotypes had the highest damage rates, with 57.2\% and 47.5\% respectively, compared to the other treatments, which showed values ranging from 16.8\% to 33.9\%. Lodging plant values ranged from 0\% to 95\%, with `Proconsul' genotype showing the highest percentage of lodging plants, compared to genotypes such as `197-1-1', `197-1', `195-2', `Fortuna', `Paloma', `Williams', `Arcos', and pearl millet, which had lodging below 1.2\%. In terms of yield, the late genotypes ('197-1-1' and `197-1') showed the highest yields, with 73.6 and 63.2 t ha-1, respectively. Sorghum genotypes `Paloma', `Fortuna', `197-1-1', and `197-1', as well as pearl millet, showed the lowest infestation rates and intensity by E. loftini, indicating that these genotypes may be potentially tolerant to E. loftini infestation. This finding could inform the development of an integrated management plan for this pest, including host tolerance.