Abstract

Several trials were conducted to evaluate the effectiveness of new insecticides in controlling the white fly Bemisia tabaci Genn, which is the vector of the Bean Golden Mosaic Virus (BGMV), at the Zapotitlan Valley and at the San Andres Experimental Station at 460 masl, during the dry season, from December 22, 1989 to May, 1990. A complete randomized block experimental design with 4 and 5 replications was used. Four trials were planted with the Rojo de Seda, Sangre de Toro and CENIA-Cuscatleco bean varieties. In the first and second trials, the chemicals bifentrin 100 EC (60 g.ai./ha) and fenpropatrin 375 EC ( 203 g.ai/ha) were efficient in controlling the whitefly, reducing the incidence of BGMV. If B. tabaci Genn is not controlled efficiently and timely, the BGMV incidence reaches 100% between 36 and 32 days after planting (DAP) on the susceptible varieties Rojo de Seda y Sangre de Toro. Seed and soil treatments combined with foliage spraying were also used in the third and fourth trials. The treatments of carbosulpan + bifentrin (1519.9 kg/ha) and acephate + bifentrin (1428 kg/ha) produced the highest yields with the resistent variety CENIA- Cuscatleco. Acephate + fenpropatrin (756.6 kg/ha), acephate + bifentrin (725.1 kg/ha) and carbofuran + fenpropatrin (636.3 g/ha) produced the highest yields with the susceptible variety Rojo de Seda. Of the tested products, fenpropatrin 375 EC showed the lowest populations of eggs and nymphs of B. tabaci Genn. There was a significant correlation between production and the time when the disease symptoms appeared. The largest Net Benefit was obtained with acephate 95% + bifentrin 100 EC treatment, followed by carbofuran 5% + bifentrin 100 EC.