Economic evaluation of lepidopterous pests in intercropped sorghum and maize in southern Honduras
2001
Vergara, Ocsar | Pitre, Henry | Parvin, David
An important constraint to sorghum [Sorghum bicolor (L.) Moench] and maize (Zea mays L.) production in southern Honduras is a lepidopterous complex. The objective of this study was to apply economic analysis to sorghum production and insect pest management strategies. Whole plant samples were taken of sorghum and maize in an on-farm study to determine insect pest densities, plant damage, and yield in plots managed under different planting dates, weed management, and insecticide application treatment systems in 1996. An economic analysis was conducted on the production systems applying direct and fixed costs and income in an appropriate model. The fall armyworm, Spodoptera frugiperda (J.E. Smith), was the most prevalent species; two other armyworm species, Metaponpneumata rogenhoferi (Moschler) and S. latifascia (Walker), were present only early in the season; and a grass looper, Mocis latipes (Guenee}, was present in mid- to late season. The lepidopterous population density was kept under crop damaging levels and yield was increased when Semevin (thiodicarb) insecticide was used as a seed protectant in combination with delayed planting date (five days after the beginning of the rainy season), delayed weed control (two to three weeks after crop emergence), and application of Lannate (methomyl) insecticide as soon as eggs or first instar larvae were observed on the crop plants. Increased levels of technology input into the intercropped production system increased sorghum production by 49% and maize production by 26% in this on-farm study. This increase in yield may be translated to an increase in farm net return of 58% and 15% for sorghum and maize, respectively.
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