Molecular variability and genetic structure of Chrysodeixis includens (Lepidoptera: Noctuidae), an important soybean defoliator in Brazil.

This study provides the first genetic characterization of the soybean looper, Chrysodeixis includens (Walker, 1857), an important defoliating pest species of soybean crops in Brazil. Population genetic variability and the genetic structure of C. includens populations were evaluated by using ISSR markers with samples from the major soybean producing regions in Brazil in the growing seasons 2011/2012. Seven different primers were applied for population characterization of the molecular variability and genetic structure of 8 soybean looper populations from 8 states of Brazil. The seven ISSR loci generated 247 bands in 246 individuals of C. includens sampled. The expected heterozygosity (HE) in the populations varied between 0.093 and 0.106, while the overall HE was 0.099, indicating low genetic diversity. The analysis of molecular variance indicated that 98% of the variability was expressed among individuals within populations (FST = 0.021, p = 0.001). The low level of polymorphism over all populations, the high levels of gene flow, and the low genetic structure are indicatives of the exchange of genetic information between the different sampled regions. Population structuring suggests the presence of two major groups which do not correlate with their geographic sampling location in Brazil. These results may indicate recent recolonization of C. includens in Brazil or migration patterns following source-sink dynamics. Furthermore, the presence of two groups within C. includens suggests that a study on development of resistance or any other genetic-based trait needs to be evaluated on both groups, and pest management in soybean fields should be aware that differences may come to the control strategies they use.

Syntomopus parisii and Leptomeraporus sp. parasitizing Melanagromyza sojae in Brazil / Syntomopus parisii e Leptomeraporus sp. parasitando Melanagromyza sojae no Brasil

ABSTRACT: This note is the first report of Syntomopus parisii De Santis 1976 and Leptomeraporus sp. (Hymenoptera, Pteromalidae) simultaneously parasitizing Melanagromyza sojae Zehntner, 1900 (Diptera, Agromyzidae) in Brazil. The Pteromalidae parasitoids are natural enemies of stem miner flies, opening perspectives for biological control of soybean stem miner fly.

RESUMO: Esta nota é o primeiro registro de Syntomopus parisii De Santis 1976 e Leptomeraporus sp. (Hymenoptera, Pteromalidae) parasitando simultaneamente Melanagromyza sojae Zehntner, 1900 (Diptera, Agromyzidae) no Brasil. Os parasitoides Pteromalidae são inimigos naturais de moscas minadoras do caule, abrindo perspectivas para o controle biológico da mosca minadora do caule da soja.