RECENT reports of severe bagworm outbreaks in Perak and Johor prompted a RM5 million emergency response – cue the usual biopesticide sprays and beneficial plants.
An additional update is that RM10mil is earmarked to tackle bagworms, mealybugs in Sabah and Ganoderma nationwide.
But here’s the real question: Will it be enough? History suggests not.
Bagworms (Metisa plana) are not new to Malaysia’s oil palm plantations.
It is a persistent and costly menace in plantations. Every few years, reports of major outbreaks emerge, causing panic in the industry.
These leaf-munching pests, if left unchecked, can devastate yields by up to 40% in just two years.
Bagworm outbreaks cause major revenue losses, especially with current crude palm oil (CPO) prices.
Recovery is slow and costly – higher fertiliser inputs drive up production costs and cut into profits.
Legally, the Plant Quarantine Act 1976 mandates control, with penalties up to RM10,000 or two years’ jail. Yet, enforcement remains lax, and outbreaks persist.
So why are we still stuck in reactive mode instead of investing in sustainable, proactive solutions?
The real issue is our reliance on short-term fixes.
The industry’s go-to response – broad-spectrum insecticides – may offer quick relief but causes lasting harm.
These chemicals kill pests and their natural predators, creating an ecological void where bagworms rebound stronger and resistant. To break this cycle, we must move beyond chemical-only strategies.
A sustainable, cost-effective solution lies in a systems-based approach that values ecological balance, biodiversity and resilience.
A smarter solution lies in strengthening nature’s own defences – through biological control. This is an important component under integrated pest management (IPM).
Parasitoid wasps, the insect world’s silent assassins, target only bagworms with surgical precision, laying eggs inside larvae that are then consumed from within.
Unlike broad-spectrum chemicals, they spare beneficial insects and cost nothing in pesticides.
But to thrive, these wasps need supportive environments – highlighting the critical role of plantation flora biodiversity.
One of the most powerful tools in IPM isn’t a chemical formula but a plant – cassia sp, a potential game-changer in pest control.
While not a new discovery, its role must be revisited, reinforced and aggressively promoted across the industry to ensure widespread adoption and lasting impact.
Cassia sp is far more than a decorative roadside plant. This leguminous shrub provides a lifeline to parasitoid wasps, ensuring their survival even in the absence of a bagworm outbreak.
Among the cousins of cassia sp, a particular species stands out, cassia cobanensis.
It has a rare natural advantage: two nectar glands per compound leaf, unlike its single-gland cassia sp cousins.
This means a non-stop nectar buffet, ensuring that parasitoid wasps have a continuous food source year-round even when the plant isn’t flowering.
Plantation field studies have shown that cassia cobanensis attracts over 300 parasitoids, while other plants like Euphorbia heterophylla or Antigonon leptopus attract fewer than 10.
This remarkable ability to sustain beneficial insect populations makes Cassia a critical player in pest management.
Now, let’s imagine an oil palm plantation where chemical sprays are the last resort rather than the default option.
Along the roadsides, vibrant Cassia plants bloom, attracting parasitoid wasps and pollinators including bees and butterflies. These wasps patrol the fronds, keeping bagworm populations in check before outbreaks can occur.
This is the vision of a sustainable, resilient plantation – one that reduces pesticide reliance, lowers costs, and enhances biodiversity. It is also a strategy backed by research.
Studies by the MPOB confirm that cassia cobanensis can support parasitoid populations for up to 30 months after planting.
That’s over two years of continuous, natural pest suppression – without a single drop of insecticide.
If cassia cobanensis is such an effective tool, why isn’t it more widely adopted or scaled up? The answer may lie in a combination of factors:
> Competing Priorities – with labour shortages and financial pressures, plantations often prioritise harvesting and revenue – crop first, everything else later.
Establishing beneficial plants like cassia cobanensis requires upfront effort and maintenance, which, though minor compared to repeated pesticide costs, is still viewed as an extra burden.
As a result, some companies shy away from proactive pest management.
In an industry focused on short-term gains now, long-term sustainability – despite its proven benefits – too often takes a back seat.
> Lack of awareness – many younger planters and smallholders may remain unaware of the full benefits of cassia sp in biological control programmes.
Without education and training, traditional pesticide use continues to be unchecked.
> Resistance to change – some growers are hesitant to shift from chemical-heavy practices to an integrated approach, fearing immediate yield losses.
The palm oil industry, like many agricultural sectors, tends to favour quick fixes over long-term investments.
But true sustainability demands foresight.
So, where do we go from here? The answer is clear. We need a paradigm shift.
The industry must transition from reactionary firefighting to proactive, science-backed pest management strategies.
> Expand cassia planting nationwide - every plantation estate should incorporate Cassia and other beneficial plants along roadsides, drainage areas and other open spaces to sustain parasitoid populations year-round.
It’s not a one-time effort – plant, replant and maintain regularly to ensure continuous ecological support.
> Enhance IPM training – growers must fully grasp the economic and ecological advantages of biodiversity-driven pest control. For those already familiar, it’s time for a refresher – because in pest management, staying ahead means continuous learning.
> Reduce chemical dependence – instead of reaching for insecticides at the first sign of an outbreak, plantation managers should evaluate ecological solutions first.
> Government and industry support – together, they must prioritise sustainable pest management by offering targeted incentives and recognising more estates that embrace biodiversity-driven strategies.
Sticking to reactive pest control is a costly, unsustainable path.
Bagworm outbreaks will continue, resistance will worsen, and production costs will rise – trapping the industry in a cycle of damage and emergency fixes. We can’t keep relying on inadequate bailouts when proven, long-term solutions are already within reach.
The future doesn’t lie in more chemicals but in harnessing nature’s defences - starting with cassia cobanensis.
Planting cassia during an outbreak is like buying an umbrella after the rain starts. Smart management means planning ahead.
To break the cycle, we must adopt nature-based solutions before the next crisis arrives. As a bonus, beneficial plants also enhance the beauty of the estate landscape.
Bagworms may be relentless but nature, when supported by human foresight, is even more powerful. It’s time for nature and man to work together, not at odds.
The real path forward is prevention, not crisis control – because lasting solutions are born when ecological wisdom meets smart management.
Joseph Tek Choon Yee has over 30 years of experience in the plantation industry, with a strong background in oil palm research and development, executive leadership and industry advocacy. The views expressed here are the writer’s own.
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