Abstract

The rust (Uromyces appendiculatus var. typica) is one of the main bean diseases in the humid Mexican tropics. The objective of this experiment is to present the results from the research conductedby the bean breeding program and the test of fungicides for controlling bean rust. Advanced lines’ evaluation, preliminary trials and regional yield trials have been conducted since 1980 and as result, the rust tolerant "Negro Veracruz" and the rust resistant "Negro Huasteco-81" varieties were released in 1981. The rust resistant "Negro Cotaxtla-91" was released in 1991. Chemical rust control trials with fungicides were started at several localities in 1990. The application of fungicides on susceptible varieties like Jamapa inereased yields by over 200 kg/ha. The fungicides which best controlled bean rust were; Hexaconazole (0.5 l/ha), Maneb (3kg/ha), and Tebuconazole (0.5 kg/ha), when applied twice before blooming. The cost of the fungicide application was paid back by 75 kg/ha of bean yield increase.