No abstract

RESUMOO aumento do cultivo da soja no Brasil tem trazido grandes avanços para a economia. Contudo, este segmento tem enfrentado grandes dificuldades para prosseguir de maneira positiva. Dentre os entraves da cultura está o problema da ferrugem asiática que está amplamente distribuída pelo país. O objetivo do trabalho foi realizar o levantamento da ocorrência da ferrugem asiática em diferentes épocas e regiões produtoras. O presente trabalho contou com a colaboração dos inspetores de defesa agropecuária da ADAPEC-TO que realizaram todo levantamento in loco nas propriedades.

Com o aumento vertiginoso da produção agrícola nacional, o uso de defensivos agrícolas tem sido um aliado do produtor no combate das pragas e doenças que acometem as lavouras. No entanto, os pequenos produtores, que compõem a maioria dos trabalhadores do campo, adquirirem defensivos em quantidades menores. Em muitos casos os pequenos produtores da agricultura familiar não possuem condições de se deslocarem até um posto ou uma central para dar a destinação correta às embalagens. Desse modo, alguns preferem enterrar, queimar, lançar em corpos hídricos, e outras práticas que comprometem a saúde

The reduction in the leaf area is one of the causes in the fall in soybean (Glycine max) productivity as it depends on the production of photoassimilates generated by the leaves, so any factor that interferes in its leaf area may affect the production. The attack of defoliating insects is among such factors. They cause a marked drop in grain yield due to its direct action, therefore, reducing the leaf area, consequently reducing the photosynthetic rate of the plant. The agronomic characteristics of the cultivars may interfere on the level of tolerance of the plant to this type of stress. The objective of this study was to evaluate the influence of defoliation levels on the vegetative and reproductive stages on the development and yield of grains in soybean cultivars. The experimental design was in randomized blocks, in a 2×11×2 factorial scheme, with four replicates. Factors consisted of defoliation stage (vegetative and reproductive), treatment levels (T1-control plant and ten treatments of artificial defoliation) and soybean cultivars (BRS 9090 RR and BRS 8890 RR). The following variables were evaluated: grain yield, dry mass of the pod, leaf dry mass, stem and root dry mass, plant height, stem diameter, number of leaves per plant, length and width of roots. It was observed that the defoliation had a negative effect on the productivity components of the cultivars, with the highest decrease in the reproductive stage, except for the treatment R5, 100% defoliation at the R5 stage, which was also reduced. In relation to the cultivars, the BRS 8890 RR was 27% better in grain yield in relation to BRS 9090 RR.