This trial aimed to evaluate the Biological Forewarning System (BFS) for controlling Yellow Sigatoka in Northern Minas Gerais, Brazil. It was carried out in the town of Nova Porteirinha. One tested 7 treatments, using 6 gross sum (GS) values (1,000; 1,300; 1,600; 1,900; 2,200, and 2,500) and the systematic disease control every 15 days. The treatments were distributed into 7 plots (120 plants/plot) with ‘Prata-Anã’ and 10 plants from each plot were weekly evaluated with regard to leaf emission rate and disease incidence on the leaves 2, 3 and 4. The more advanced lesion stages and their intensity were used to calculate the gross sum, which aided in decision-making for chemical control. One collected data on production and firmness, pH, and acidity analysis of fruits. For the GS 2,500 treatment, taking into account 2-year evaluation, there was a reduction from 12 to 3 applications, i.e. 75% less fungicide was applied, without loss in productivity. Therefore, one suggests, taking into account the conditions of Nova Porteirinha, the application of BFS for chemical control of Yellow Sigatoka, using the GS value of 2,500 as an indicator of the correct time to perform pulverization.