Biology and nutritional indexes of Spodoptera frugiperda (Lepidoptera: Noctuidae) in saccharine sorghum.
Saccharine sorghum has been analyzed as a supplementary prime matter for ethanol production, especially during the sugarcane off-season period. However, it has proven to be highly susceptible to insect attacks during the cultivation cycle. The fall armyworm should be emphasized due to its voracity and high damage capacity enhanced by feeding-caused decrease in photosynthetic area. Current analysis studies the biology and determines the nutritional indexes of Spodoptera frugiperda in saccharine sorghum. Cultivars of saccharine sorghum BRS 506, BRS 509 and BRS 511 were evaluated. Duration and survival of the egg, caterpillar, pre-pupal and pupal phases were determined, coupled to weight of pupae and caterpillar, life span, fecundity and pre-egg laying period. Although S. frugiperda completed its life cycle on cultivars BRS 506 and BRS 511, egg-laying and egg feasibility rates were low, whereas insects did not lay eggs on cultivar BRS 509. There was no significant difference in feeding intake by S. frugiperda among these three sorghum cultivars. Results suggest that saccharine sorghum is not a suitable host for S. frugiperda. Biological data reveal that the three saccharine sorghum cultivars are recommended for the grain production system since the number of specimens of the next generation is low or null.