Start Date: Aug 17, 2009
End Date: Aug 16, 2014
Candidate endophytes (Trichoderma species) have been screened to demonstrate their ability to colonize cacao and for biocontrol efficacy against cacao pathogens. At present, isolates to be considered for further study include 15 isolates previously screened for biocontrol and endophytic efficacy in cacao by ARS, and several isolates of specific interest to INIAP scientists. Four Bacillus isolates previously collected in Ecuador and screened by collaborators for biocontrol and endophytic activity in cacao may also be considered. The capacity of different formulations to enhance biocontrol efficacy will be determined. The formulations used to date in biocontrol research in cacao have incorporated starches (as carriers), surfactants, or water alone. Lab-based research on formulations with Trichoderma isolates indicate a significant benefit to Trichoderma efficacy in response to added nutrients, humectants, and vegetable oils (corn oil). Initially, these formulations (including nutrients, humectants, and oils) will be evaluated for their abilities to enhance Trichoderma biocontrol efficacy in small scale and short term field studies. Formulation concepts will be optimized as to specific components (for example, readily available nutrient sources), concentrations, and application timing. Standard protocols will be developed for rapid evaluation of biocontrol agents, formulations, and their interactions in the field. In collaboration with cooperating institutions, large scale field trials of promising endophyte formulations with biocontrol potential will be conducted. The economic impact of biocontrol strategies for the control of disease will be determined. The best cultural practices, integrated pest management (IPM) practices, and cacao clonal material selected for disease resistance and yield will be evaluated. The first three treatment combinations will include control (no management), best cultural practices, best cultural and IPM practices combined, and best cultural and IPM practices combined with superior cacao clonal material. The fourth treatment involves rejuvenation of cacao trees by topping and grafting. Regrowth from the top of cacao tree stumps will be grafted with selected superior hybrid national cacao clones. Twenty-five percent of the trees within the selected plots will be rejuvenated every year.