The Borer moth Crocidosema aporema (Walshingham 1914) (Lepidoptera: Tortricidae) is a potentially harmful species to the soybean crops, particularly in the areas of temperate weather, like those in the southernmost section of Rio Grande do Sul State. Level of damage caused on the late crops of the season is influenced by sowing time and varies according to the genotype. Currently the available information in Brazil pertinent to the variaton on C. aporema onslaught on commercial genotypes is scarce. This paper evaluated the damage provoked on late-season crops upon eighteen soybean commercial genotypes, compared in two groups according to relative maturity degree (RMD), in the V.4, V.6, V.8, V.10, R.2 and R.4 phenological states, during the agricultural year 2009/2010, in the Campanha Region of Rio Grande do Sul. Significant differences on attack levels were found among the longer cycle genotypes, being the 'Fundacep 59' cultivar the least attacked in this group and 'Fepagro RS-10' and 'Fundacep 45 - Missions' cultivars the genotypes presenting the highest damage to the crops. Level of damage varied differently according to the phenological stage for each genotype; there were cultivars suffering from highest attack levels during their vegetative stages and cultivars under heavier attack on reproductive stages. Monitoring of damage to the late-season crops identified only once, in the 'Fepagro RS-10' cultivar, the need for control adoption, when the level of 30% of attacked crops by C. aporema was reached.
Crocidosema aporema; pest-resistant crops; Glycine max
