Número de gerações de um percevejo e seu parasitoide e da severidade da ferrugem asiática em soja, simulados em cenários de clima e manejo no norte do RS

Abstract

The objective of this study was to simulate the number of generations of a soybean insect pest (Euschistus heros) and its parasitoid (Telenomus podisi) and a fungal disease (soybean rust caused by Phakopsora pachyrhizi) as infl uenced by sowing date, cultivar and time of occurrence of the pest and the disease. Bioclimatic models that predict development of the organisms and severity of the disease were integrated into a crop simulation model of soybean (DSSAT) that predicted phenological stages of the crop for scenarios of sowing data and cultivar maturity group in a long time series of daily meteorological data to Passo Fundo and Santa Rosa, Rio Grande do Sul State, Brazil. The results showed that regardless of the maturity group, the earlier the sowing date and the time of occurrence of E. heros in the fi eld, the greater its number of generations (2 to 3) until physiological maturity. For T. podisi, a higher number of generations (5 to 6) was estimated for the earlier sowing dates and late-maturing cultivars. For soybean rust no signifi cant trends of reduction in the mean disease severity was observed when advocated practices such as early sowing and early-maturing cultivars were used.