Utilization of Biological Control Agents against Phytophthora palmivora Causing Pod Rot Disease in Cacao

Abstract

Cacao black pod rot, caused by Phytophthora palmivora, is an economically serious problem in all cacao-producing regions, leading to global yield loss and tree deaths. With the advent of Republic Act 10068, also known as the Organic Agriculture Act of 2010, the state is searching for and encouraging sustainable agriculture. Hence, this study was conducted to determine the antagonistic effects of the different biological control agents against P. palmivora and identify the most effective biological control agents against cacao pod rot. Conducted at a laboratory, the experiment was laid out in Complete Randomized Design (CRD) and replicated three times with five samples of cacao pods per replication. Treatments used were as follows; T1- Negative control, T2- P. palmivora, T3- Chemical control, T4- Bacillus subtilis, T5- Bacillus amyloliquefaciens, T6- Trichoderma harzianum. The in vitro test was done using a dual culture technique, while the in vivo test was done through a detached pod test. The dual culture test showed that T. harzianum reduced P. palmivora radial growth to 6.77mm with a percent growth inhibition of 70.54%. Moreover, the detached pod test recorded no disease incidence, severity, and incubation period in pods treated with T. harzianum. Whereas, the longer incubation period was noted in pods treated with chemical control at 4.27 days. Moreover, the highest degree of control was recorded in pods treated with T. harzianum (100%). These findings emphasized the potential of T. harzianum as a sustainable and effective solution for combating cacao black pod rot and promoting sustainable agriculture.