Abstract

SOTO-MUNOZ, L.  and  MARTINEZ-PENICHE, R. A.. Efect of antagonic yeasts and sodium bicarbonate on Penicillium expansum Link in two apple varieties. Rev. Chapingo Ser.Hortic [online]. 2009, vol.15, n.2, pp.211-216. ISSN 2007-4034.

As the use of chemical fungicides to control postharvest diseases of apple as Penicillium expansum Link is not entirely accepted, antagonist microorganisms as yeasts are employed. However, due to their limited effectiveness they are proposed to be combined with substances of natural origin. To evaluate the efficacy of different strains of antagonistic yeasts in combination with sodium bicarbonate (SBC) to control P. expansum, 'Golden Delicious' and 'Red Delicious' apples were treated with three levels of SBC and inoculated with a given concentration of ten antagonistic yeasts separately in wounds where a spore suspension of P. expansum (1 x 10⁴ UFC), was then placed. Lesion diameter and incidence were measured after ten days of incubation. 'Red Delicious' was less susceptible to P. expansum than 'Golden Delicious' (diameter lesion of 1.52 cm vs 2.01 cm). Yeasts with the highest antagonist capacity on P. expansum were 22-218, 8-121 y 26-224 (Torulaspora spp) reducing the development of fungus in 89, 81.8 y 84.3% respectively. SBC did not reduce the development of fungus, but at 2% it enhanced the antagonistic effect of yeasts 23-61 and 3-5241 in 26.4 y 23.1% respectively. Yeast 22-218 showed the major antagonism against P. expansum in 'Golden Delicious' diminishing the lesion diameter at 0.1 cm, while yeasts 22-224 and 8-121 did in 'Red Delicious' diminishing injury in 91.7 and 91% respectively.

Keywords : Malus domestica Borkh; Blue mold; biological control; 'Red Delicious'; 'Golden Delicious'.