Nanoparticles in the management of brown eye spot in coffee

Brown eye spot (Cercospora coffeicola)is one of the main diseases of coffee (Coffea arabica L.)and represents a serious phytosanitary problem for the crop. Among the disease management strategies, the use of balanced mineral nutrition is recommended. In this context, the supply of micronutrients and elements in a nanoparticle (NP)form has been studied due to the unique properties of NPs. The objective of this study was to evaluate the effects of different NPs on the C. coffeicola x coffee pathosystem. The effect of five NPs (copper-Cu, manganese-Mn, zinc-Zn, silver-Ag, and boron-B)and the fungicide azoxystrobin + cyproconazole at five doses (3, 50, 100, 250, 500 mg L?1), on the sporulation and mycelial growth rate (MGR)of C. coffeicola were quantified. The most effective in vitro dose (500 mg L?1)was applied to coffee seedlings Mundo Novo 376/4 cultivar inoculated with C. coffeicola. The area under the disease progress curve (AUDPC), compound phenolic, lignin soluble and chlorophyll content were evaluated. The AgNP, CuNP, MnNP, ZnNP and fungicide reduced the germination of C. coffeicola spores. The addition of fungicide, BNP, CuNP, ZnNP and MnNP to the culture medium at the dose of 500 mg L?1 reduced the mycelial growth by approximately 100 percent, compared to the control. Lower AUDPC's were recorded for coffee seedlings sprayed with fungicide and AgNP.