InfoSAWIT, JAKARTA – A new hope has emerged in the fight against the rhinoceros beetle (Oryctes rhinoceros), a major pest for palm oil and coconut plantations in Southeast Asia. A collaborative study published in the report "First Report: Senna multijuga Subsp. multijuga (Fabales: Fabaceae) as an Attractant and Bioinsecticide for Oryctes rhinoceros (Coleoptera: Scarabaeidae)" reveals that a local plant known as the "Golden Shower Tree" has dual potential as a natural attractant and bio-insecticide.

The research involved a team of researchers, including Ruli Wandri, Samsu Alam, Shervinia Dwi Ayundra, Azharudin Apriansa, Dwi Asmono, Subeki, Yuyun Fitriana, Rosma Hasibuan, and Radix Suharjo. The study began in 2020 at a plantation of PT Sampoerna Agro Tbk in Indonesia, where many rhinoceros beetles were observed being attracted to "Golden Shower Trees" and subsequently dying after feeding on parts of the plant.

Initially, the identity of the plant was unknown. The research team conducted a series of morphological and genetic sequence analyses, including on the MaturaseK, rps16, and rpl16 genes. The results confirmed the plant to be Senna multijuga, a species in the Fabaceae family found in South America and several parts of Asia, including Indonesia.

"This identification is significant because it's the first time Senna multijuga has been reported to have properties as both an attractant and a bio-insecticide against the rhinoceros beetle," the research team stated in their report, as cited by InfoSAWIT from the open-access scientific publisher MDPI on Wednesday (9/17/2025).

More Effective Than Pheromone Traps

Field tests conducted over nine months showed surprising results. Of the 25 S. multijuga trees observed, the number of attracted and trapped rhinoceros beetles reached 836. This was significantly higher than the 512 beetles caught using 299 synthetic pheromone traps based on ethyl 4-methyloctanoate (E4-MO), which has long been the standard attractant.

"This means that the ability of S. multijuga as an attractant is 1.6 times more effective than the commonly used synthetic pheromones," the researchers noted. This finding opens the door to a cheaper, more efficient, and environmentally friendly method of pest control.

In addition to attracting the beetles, extracts from the leaves, stems, and bark of S. multijuga also showed insecticidal effects. Laboratory tests found that the leaves were more effective at killing larvae, while the stems and bark were capable of causing mortality in both larvae and adult beetles.

The mortality rate for adult beetles ranged from 12.5% to 25%, while for larvae it was between 1.25% and 3.75%. Although the percentages are relatively low, the results confirm the presence of active compounds in the plant. One of these is suspected to be a pyridine alkaloid, a chemical compound also known to be active in many synthetic insecticides.

Challenges and New Hope

For palm oil plantations, especially in Indonesia, this discovery is highly relevant. Data from PT Sampoerna Agro noted that in 2020, rhinoceros beetle attacks on young oil palms (TBM) affected 1,764 hectares, with varying levels of infestation up to 38%. Control costs reached Rp14.7 million per hectare, using a combination of manual methods, pheromone traps, and chemical insecticides.

"With this finding, S. multijuga could be a new, more sustainable alternative. However, further research is still needed to identify its active compounds and confirm its effectiveness on a large plantation scale," the research team stated.

As global market demands for a more environmentally friendly palm oil industry grow, bio-based pest control innovations like this are considered strategic. In addition to reducing reliance on chemical insecticides that risk environmental pollution, the use of local plants also aligns with the principles of sustainability.

"This finding is just the beginning. Moving forward, research must go further to extract the active compounds, test their effectiveness in various agro-ecosystem conditions, and evaluate their long-term impact," the researchers concluded. (T2)