The Effectiveness of Some Essential Oils as Botanical Fungicides Against Inhibition of the Growth Cocoa Fruit Rot Phytopthora Palmivora

Abstract

The main disease in cocoa pods is fruit rot caused by the fungi Phytophthora palmivora. The loss caused by P. palmivora is almost 90%. Currently, the control is still using synthetic fungicides which are harmful to humans and the environment. Therefore, the use of essential oils as fungicides is a safe control for the environment. This study aims to obtain a combination of nutmeg, cloves, and citronella that are effective as a botanical fungicide to control cocoa pod rot disease. The study was conducted at the Lampung State Polytechnic Plant Laboratory using a completely randomized design with 8 treatments which were repeated 5 times. The treatments tested were (1) negative control (water), (2) positive control (synthetic fungicide), (3) nutmeg oil, (4) clove oil, (5) citronella oil, (6) nutmeg + clove oil, (7) nutmeg oil + citronella, and (8) Clove and citronella oil. Essential oil testing on the growth of P. palmivora was carried out in vitro by inoculating agar pieces containing fungal culture on the surface of PDA containing essential oils. The results showed that all essential oil combination treatments were able to suppress the growth of the P. palmivora on PDA media. The combination of nutmeg oil and clove oil can suppress fungal growth by 77%, while the combination of nutmeg oil and citronella oil reaches 56.5% and the combination of clove oil and citronella oil reaches 27%. However, the single treatment that best suppressed the growth of P. palmivora was citronella oil, which was 32.8%.