Curative and Suppressive Activities of Essential Tea Tree Oil against Fungal Plant Pathogens

Moshe Reuveni,Marcel Barbier,Ethel Sanches

doi:10.3390/agronomy10040609

Abstract

Timorex Gold based on the essential tea tree oil (TTO) derived from the Australian tea tree oil (Melaleuca alternifolia) plant has demonstrated high efficacy and a strong curative activity against black Sigatoka in banana and controlled it in stages 1, 2, 3, and 4 of disease development. Transmission electron microscope (TEM) examination of infected leaf sections treated with Timorex Gold revealed disruption of the fungal cell membrane and destruction of the fungal cell wall in disease development stages 4 and 5. Mineral oil and the fungicide difenoconazole, when applied alone, had no curative effect and did not disrupt the fungal cell wall or membrane, similar to the untreated control tissue. A single spray of Timorex Gold effectively controlled and suppressed powdery mildew in cucumber by causing the disappearance of 99% of established colonies recorded 1 or 2 days after the application and was effective for up to 8 days after application. Scanning electron microscope (SEM) examination of infected and Timorex Gold-treated leaves indicated strong shrinkage and disruption of fungal hyphae and conidial cells. The curative and suppressive modes of action of the Timorex Gold may explain its success in controlling both diseases.

Highlights

Black leaf streak, known as black Sigatoka disease, is caused by Pseudocercospora fijiensis Morelet and is considered the most damaging and costly disease of commercial bananas and plantains [1,2]
In the present study we investigated the curative activity of Timorex Gold against M. fijiensis hyphae on banana leaves and its suppressive activity against powdery mildew in cucumber leaves
This study demonstrated that the tea tree oil-based product Timorex Gold effectively suppressed powdery mildew development on cucumber plants

Summary

Introduction

Known as black Sigatoka disease, is caused by Pseudocercospora fijiensis (teleomorph Mycosphaerella fijiensis) Morelet and is considered the most damaging and costly disease of commercial bananas and plantains [1,2]. Damage caused by this disease significantly reduces the photosynthesizing area of the leaf, and fruit-yield losses can reach 50% through premature maturation—a very serious problem in fruit grown for export [1,3,4]. Disease control is generally achieved by the use of fungicidal chemicals, including sulphur and sterol biosynthesis inhibitors. The emergence of fungicide-insensitive variants of the pathogen has been reported [6]

Methods

Results

Discussion

Conclusion