Management of Fusarium wilt of bananas in Minas Gerais, Brazil

The North of Minas Gerais is a major banana production region in Brazil. 'Prata Anã' (AAB, Pome subgroup), the predominant cultivar in this area, is severely affected by Fusarium wilt (Fusarium oxysporum f. sp. cubense - Foc) race 1. To assess alternative production strategies in soils infested with Foc, an experiment was established in a highly Foc-infected area. Tissue culture planting materials of 'Silk' (AAB, highly susceptible), 'Prata Anã' (AAB, moderately susceptible) and 'BRS Princesa' (AAAB, moderately resistant) were planted comparing four treatments. Full treatment consisted of silicon, Trichoderma harzianum, compost, differentiated sources of NPK and Crotalaria juncea as a cover crop. Medium and minimum treatments included selected components of the full package. Control plots followed local practices. The first symptoms of Fusarium wilt were observed at 3 months after planting (MAP) in 'Silk' (incidence = 30%) and reached 100% at 9 MAP in this cultivar. Symptoms in 'Prata Anã' were observed at 6 MAP (incidence = 8%). At 14 MAP the internal severity index values recorded in 'Prata Anã' were: 23% (full), 26% (medium), 57% (minimum) and 81% (control) with average productivity of 22.9, 19.4, 18.8 and 8.9 tons ha-1 of commercial fruit, respectively. No symptoms of Fusarium wilt were observed in 'BRS Princesa' after the first cropping cycle whatever the treatment. Our preliminary data show the potential of soil health-oriented practices, but also highlight the importance of genetic resistance to manage Fusarium wilt on infected areas. While in 'Silk', our treatments were not efficient to reduce the disease in the first crop cycle, in 'Prata Anã' a reduction of about 58% was observed under the full treatment with an increase of 157.3% in commercial fruit production. The results to date suggest that banana production in Foc-infected soils depends not only on some level of cultivar resistance, but also multiple practices that promote soil suppressiveness against Fusarium wilt and plant defences.