The findings are important because sheath rot remains one of the most persistent challenges in maize production. The fungus can spread through both soil and air and survive for more than two years by producing dormant structures called sclerotia. As agriculture faces growing pressure to reduce chemical pesticide use while maintaining crop productivity, plant-based biopesticides are receiving increased attention.
Turning Local Plant Resources Into Crop Protection Solutions
Indonesia is one of the world’s richest biodiversity regions and possesses extensive plant resources that may support sustainable agriculture. Botanical pesticides derived from local plants are increasingly viewed as practical alternatives to conventional chemical treatments.
Eucalyptus leaves have long been recognized in Indonesia for their medicinal and essential oil applications. However, their agricultural potential has received less public attention.
According to Handry R. D. Amanupunyo of Pattimura University, eucalyptus leaves contain bioactive compounds including flavonoids, tannins, saponins, terpenoids, alkaloids, and essential oils that are known to exhibit antimicrobial activity. While previous studies explored their antibacterial and insecticidal functions, evidence regarding antifungal performance remained limited.
This research expands that understanding by testing whether eucalyptus leaf extract can inhibit fungal growth associated with corn disease.
How the Study Was Conducted
The experiment was carried out from April 9 to April 20, 2025, in the Laboratory of the Faculty of Agriculture at Pattimura University.
Researchers collected infected corn sheath samples containing Rhizoctonia solani and isolated the fungus under controlled laboratory conditions.
Two forms of eucalyptus extract were prepared:
- Fresh eucalyptus leaf extract
- Residual eucalyptus leaf extract obtained after processing
Each extract was tested at several concentrations ranging from 0.5 mL to 2.0 mL. The extracts were mixed into fungal growth media and compared with Dithane, a commonly used synthetic fungicide.
Researchers evaluated performance by observing:
- Expansion of fungal colony diameter
- Percentage of fungal growth inhibition
- Timing of sclerotia formation, which indicates fungal survival capability under stress conditions
Statistical analysis using Analysis of Variance (ANOVA) identified meaningful differences among treatments.
Residual Eucalyptus Extract Delivered the Strongest Natural Suppression
The experiment revealed that all eucalyptus treatments influenced fungal development, but residual extract consistently produced stronger inhibition than fresh leaf extract.
Untreated fungal colonies expanded to an average diameter of approximately 7.01 cm.
By comparison:
- Dithane treatment reduced colony growth to approximately 0.50 cm
- Residual eucalyptus extract (2.0 mL) reduced colony growth to approximately 1.07 cm
- Residual eucalyptus extract (1.5 mL) reduced growth to approximately 1.35 cm
- Residual eucalyptus extract (1.0 mL) reduced growth to approximately 1.64 cm
When converted into inhibition performance:
- Dithane achieved approximately 93% inhibition
- Residual eucalyptus extract (2.0 mL) achieved approximately 85% inhibition
- Residual eucalyptus extract (1.5 mL) achieved approximately 81% inhibition
- Residual eucalyptus extract (1.0 mL) achieved approximately 77% inhibition
The highest-performing natural treatment approached the effectiveness of the synthetic fungicide.
Researchers also observed that residual extract delayed the appearance of sclerotia, structures that allow the fungus to survive in unfavorable environments. Slower sclerotia formation suggests reduced pathogen resilience.
Why Eucalyptus Leaves Affect Fungal Growth
The suppression effect appears to result from multiple active compounds acting simultaneously.
Flavonoids may disrupt fungal cell membranes and interfere with energy metabolism. Tannins may weaken fungal cell walls by limiting structural synthesis. Alkaloids may interfere with nucleic acid formation and damage internal cellular processes.
Essential oil compounds—particularly 1,8-cineole—are also believed to alter membrane integrity and trigger leakage of essential cellular contents.
Together, these biological effects reduce fungal growth and weaken the pathogen’s ability to establish infection.
Implications for Sustainable Agriculture and Agricultural Waste Utilization
The study highlights an emerging opportunity for agricultural waste valorization.
Residual eucalyptus leaves, often treated as byproducts after processing, may become raw materials for biopesticide development. If future field trials confirm laboratory performance, farmers could gain access to crop protection methods that reduce chemical dependency and support environmentally responsible production.
The findings also align with broader agricultural priorities including circular economy practices, lower chemical residues, and greater use of locally available biological resources.
As ethically paraphrased from the interpretation presented by Handry R. D. Amanupunyo and Pattimura University, eucalyptus-derived biopesticides may contribute to more sustainable crop protection systems while preserving agricultural quality and reducing environmental burden.
Author Profile
Handry R. D. Amanupunyo is a researcher from the Faculty of Agriculture, Pattimura University, Indonesia. His academic work focuses on plant protection, plant disease management, agricultural microbiology, and the development of environmentally friendly biopesticides derived from local biological resources.
Source
Article Title: Effectiveness of Inhibition of Cauliflower Leaves (Melaleuca leucadendra L.) Against the Cause of Corn Sheld ROT (Rhizoctonia solani) in Vitro
Journal: Formosa Journal of Science and Technology (FJST)
Publication Year: 2026
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