Abstract

MOGOLLON ORTIZ, Ángela María  and  CASTANO ZAPATA, Jairo. In vitro Evaluation of Inductors of Resistance on Mycosphaerella fijiensis Morelet. Rev. Fac. Nac. Agron. Medellín [online]. 2012, vol.65, n.1, pp.6327-6336. ISSN 0304-2847.

Abstract. Black sigatoka (Mycosphaerella fijiensis M.), is the most important foliar disease of both banana and plantain, causing yield losses between 30 and 40%. Its management based on fungicides, represents 40% of the production costs. In order to find new alternatives to manage the disease in plantain, it was evaluated in vitro the effect on the fungus of the inductors of resistance salicylic acid (SA), acibenzolar-S-methyl (ASM), 2,6-dicloroisonicotinic acid (INA), 3-butanoic acid (BABA) and potassium phosphite, as well the fungicides propoconazole and clorothalonil. Each product was considered as an independent experiment in a completely randomized design in one way and conformed by four treatments and fifteen repetitions per treatment. It was evaluated: number of colonies cm^2-1, size of colonies (mm), sporulation and germination (%) of M. fijiensis. The effect of the inductors of resistance did not show total inhibition on the fungus growth; however, all the variables, except the germination with SA, INA and BABA, showed significant differences between the concentrations evaluated. The average number of colonies cm^2-1 with the inductors of resistance ranged between 1.58 and 3.5, while the control had 2.1 and 3.8; the colony size ranged between 1 and 4.6 mm and the control 3.8 to 4.6 mm; the number of conidia mL^-1 ranged between 1,142 and 4,700 and in the control 4,386 and 5,783, and the germination of conidia with ASM and potassium phosphite ranged between 27 and 72.6% while in the control was between 74 and 79%. Both fungicides propiconazole and chlorothalonil totally inhibited the fungus growth.

Keywords : Paracercospora fijiensis; black sigatoka; fungus; agar V8.

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