Panama disease, caused by Fusarium oxysporum f. sp. cubense, is a limiting factor for banana (Musa spp.) production. The most efficient control measure consists of the use of resistant cultivars. Inducing resistance in the host is an alternative to be evaluated. The present investigation studied the effect of acibenzolar-S-methyl (ASM) and DL-b-amino-n-butyric acid (BABA) resistance inducers on the germination and mycelial growth of F. oxysporum f. sp. cubense in vitro at the following rates of: 0; 0.050; 0.100; 0.150; 0.200; 0.250 and 0.500 mg.ml-1 and 0; 0.525; 1.050; 1.575; 2.100; 2.625 and 3.150 mg.ml-1, respectively, using F. oxysporum f. sp. cubense at 1 x 10³ conidia.ml-1 as inoculum. The ASM and BABA were sprayed at the rates of: 0; 0.050; 0.100; 0.150; 0.200; 0.250 mg.ml-1 and 0; 0.525; 1.050; 1.575; 2.100; 2.625 mg.ml-1, respectively, on in vitro produced banana plants varieties 'Maçã' and 'Grande Naine' under greenhouse conditions. Roots were inoculated by immersion in a conidial suspension of F. oxysporum f. sp. cubense at 1 x 10³ units.ml-1 four, six and eight weeks after induction. Disease severity was measured 20 days after inoculation using a disease index. The results pointed out that BABA at 2.100 mg.ml-1, decreased disease severity in the var. 'Maçã' by 35.0% when applied four weeks before inoculation. The ASM at 0.500 mg.ml-1, inhibited in vitro germination of conidia. BA BA at the rates used, did not affect the mycelial growth of the fungus. In 'Grande Naine', BABA at 0.525 mg.ml-1, reduced disease severity by 21.55% for the inoculation times. No ASM effect was observed for the severity of Panama disease.
mal-do-Panamá; aquired systemic resistance; Musa spp
