The effects of applying micronutrients, cattle manure, lime and splitting application of NPK fertilizers on the yield and the incidence of witches' broom disease of cacao caused by Crinipellis perniciosa were determined in two experiments carried out on structured Terra Roxa soil (TR) and Yellow Latosol (LA), in Pará State, from 1988 to 1993, after the slash and burn of the forest. The hybrid (Sca 6 x Be 10) cacao crop was introduced utilizing banana (Musa spp.), as temporary shading, and a leguminous tree (Erythrina poeppigiana) or Gmelina arborea, as permanente shading, The experimental design was a randomized block with three replications of 20 cacao trees per plot in each soil. Cacao yield data showed that there was no interaction between treatments and soils or cropping year. The highest yields were obtained by splitting NPK fertilizers three times a year or by applying NPK plus zinc, which increased (P < 0,05) production by 27,5% and 10,9%, respectively. Lowest witches' broom pod infection (P < 0,05) occurred when soil was treated with a micronutrient mix (Bo, Cu, Zn, Fe and Mo) or with cattle manure at the rate of 5 t ha-1. The most promising fertilizer strategy to increase yield of cocoa was splitting the rate of a NPK fertilizer (60 kg ha-1 of N, P(2)0(5) and K(2)0) three times a year. The importance of micronutrients, cattle manure and liming on pod infection by witches' broom disease deserves more attention in future research.
micronutrient; NPK; cattle manure; Yellow Latosol; Terra Roxa