Updated on 18 September 2024 by: Yeo Yu Teng
Pest Control Challenges in Plantation | What are Beneficial Plants | How to Grow Beneficial Plants | Most Effective Plant based on Research | An All-Rounded Approach: Integrated Pest Management | IPM in Sustainability Certifications
When you visit our plantations, you’ll see splashes of yellow, white, and pink flowers among the roadside shrubs. These blooms aren’t just there for decoration – they play a critical role in pest control. Let’s explore how beneficial insectary plants like Cassia cobanensis, Turnera subulata, Antigonon leptopus, and Euphorbia heterophylla help reduce the need for chemical pesticides, offering a sustainable way to manage leaf-eating caterpillars.
Pest Control Challenges in Plantations
Oil palm is an essential crop for Indonesia, significantly impacting the nation’s economy. From 2014 to 2022, it contributed 9 to 17% of Indonesia’s Gross Domestic Product (GDP) [1]. The oil produced from these palms, known as palm oil, is Indonesia’s second-largest export, bringing in between USD 15 to 30 billion each year [2]. However, like all crops, oil palms are vulnerable to pests, which can drastically reduce yields.
Damage From Leaf-Eating Caterpillars
Leaf-eating caterpillars like nettle caterpillars and bagworms are typically found in small numbers in palm plantations. However, if their populations aren’t properly managed and they begin to surge, they can cause significant damage to the palm leaves. For example, bagworms can cause crop losses of 30 to 50% over two years if they defoliate more than 50% of the leaves [3]. Plants rely on their leaves to capture sunlight for photosynthesis, a process by which they produce food for themselves. Damage to the leaves reduces photosynthetic activity, and the plant will have less energy to produce fruits.
Chemical Insecticides Can Be Costly
Traditional pest control methods often rely on chemical insecticides. These can be sprayed onto the palm’s foliage to kill pests on contact. Some types can be injected into the palm’s trunk, where the active ingredients travel through the palm’s transport system to the leaves, effectively targeting leaf-eating caterpillars without harming other non-targeted organisms.
However, if the same pesticide is used over an extended period, pests can quickly develop resistance to these chemicals, leading to repeated outbreaks. That’s why we need to explore methods that combine various approaches to control pests in a more environmentally friendly way.
What Are Beneficial Plants
Beneficial plants are grown to attract and boost the population of natural enemies of leaf-eating caterpillars, helping to control them naturally and reduce the need for pesticides. Beneficial plants work by providing shelter under their bushy leaf covers and producing nectar, which insects love to feed on. This nectar doesn’t just attract insects but also helps them live longer [4]. By creating an inviting environment, these plants allow natural enemies of leaf-eating caterpillars, like predators and parasitoids, to thrive and multiply.
Predators of Leaf-Eating Pests
In our plantations, predators such as Cantheconidae furcellata are on patrol, hunting down the nettle caterpillars and bagworms. These hunters use their sharp mouthpieces to pierce into their prey’s body and suck their innards, literally sucking the life out of them. Other predator examples, like Sycanus dichotomus and Platynopus melanoleueus, also play their part in keeping pest populations in check.
In some cases, these beneficial insects are bred in insectaries and then released into plantations to quickly boost their populations. This allows them to control pests more effectively by preying on them sooner and keeping their numbers within acceptable limits.
“At Musim Mas, we rear Cantheconidae furcellata and Sycanus dichotomus and release them at least once a month,” says Wentricho Manullang, Senior Research Officer at Musim Mas’ R&D Crop Protection Unit.
Parasitoids of Leaf-Eating Caterpillars
Meanwhile, parasitoids use a sneakier method. These tiny parasitic wasps lay their eggs on or inside caterpillars. When the eggs hatch, the larvae feed on the caterpillars, either from the outsideor from within. Parasitoids are harmless to humans. Some helpful ones include Ichneumonids like Spinaria spinator and Goryphus spp., and Braconids like Aulosaphes pyschidivorus and Dolichogenidea metesae.
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How to Grow Beneficial Plants
At Musim Mas plantations, we strategically plant a mix of beneficial plants along the roads near our oil palms. “We plant 10-meter-wide strips of these mixed plants per hectare, with a careful balance of 60% Cassia cobanensis, 20% Antigonon leptopus, and 20% Turnera subulata,” explains Cheong Yew Loong, Senior Manager at Musim Mas’ R&D Crop Protection Unit. “We also encourage Euphorbia heterophylla to grow naturally in the landscape.” Let’s dive into what makes each of these plants so effective.
Cassia cobanensis
Cassia cobanensis is the most common beneficial plant found in oil palm plantations. Belonging to the legume family, like peanuts and soybeans, it thrives along plantation roads and in open spaces with plenty of sunlight and rainfall. This perennial shrub grows up to 1 meter tall and features oblong elliptic-shaped leaves covered with fine hairs [5]. The bases of the leaves have nectar-producing glands that attract insects. Cassia cobanensis blooms with yellow-orange flowers and requires minimal maintenance once established. It typically takes about a year for the plant to attract enough parasitoids and establish a sufficient population to make a noticeable impact.
Turnera subulata
Also known as white alder, Turnera subulata is a perennial herb that can remain productive for up to five years under optimal conditions. Thriving in full sun, it grows up to 80 centimeters tall [6]. Its lanceolate leaves have toothed margins covered in short white hairs. The plant blooms in the morning, opening around 8 AM and closing by noon. The flowers are cream-colored, adding to their aesthetic appeal in plantation landscapes.
Antigonon leptopus
Antigonon leptopus, commonly known as Mexican Creeper or Coral Vine, is a perennial vine admired for its vibrant pink flowers. It blooms prolifically under bright sunlight, providing abundant nectar for parasites and parasitoids of leaf-eating caterpillars. The leaves are heart-shaped, light green, and prominently veined with wavy margins. This climber can reach heights of up to 12 meters and spread up to 6 meters wide [7]. It’s so vigorous that it has been known to cover the exterior of tall buildings like the 27-story Oasis Hotel Downtown in Singapore, showcasing its robust growth [8].
Euphorbia heterophylla
Euphorbia heterophylla, also called Mexican Fireplant or Wild Poinsettia, originated in Mexico but can be found worldwide. It’s an annual herb that grows up to 1.5 meters tall [9]. The small flowers lack petals but are still effective in their ecological role.
Most Effective Plant Based on Research
Cassia cobanensis stands out as the top choice for attracting most of the parasitoids which prey on leaf-eating caterpillars. Research by Basri, Norman, and Othman in 2001 showed that over 300 parasitoids were drawn to Cassia cobanensis, while other plants, like Euphorbia heterophylla, attracted fewer than 10 each [10]. Cassia cobanensis is also robust and low-maintenance, making it an ideal host for natural predators, especially parasitoids.
What’s more, Cassia cobanensis supports parasitoids for a long time, keeping the Metisa plana bagworm population under control even 30 months after planting. The nectar it produces under its leaf axils is easy for parasitoids to access and is rich in sucrose, which these beneficial insects love. This makes Cassia cobanensis a perfect habitat for them to thrive. Nevertheless, it’s crucial to grow a mix of plants.
An All-Rounded Approach: Integrated Pest Management
Growing beneficial plants is just one part of our holistic Integrated Pest Management (IPM) strategy, which aims to control pests sustainably and effectively. IPM combines various tactics into four layers of control: cultural, physical, biological, and chemical. Beneficial plants fall under cultural control, as they create an environment that naturally limits pest populations. The predatory and parasitoid insects attracted by these plants are a form of biological control. While we’ve focused on using beneficial flowers to manage leaf-eating caterpillars, different pests require different measures. For example, we use barn owls to control rat populations that would otherwise eat the oil palm fruits.
IPM in Sustainability Certifications
Adopting IPM is crucial for meeting the Indonesian Sustainable Palm Oil (ISPO) certification requirements, mandatory for all oil palm plantation businesses in Indonesia. Since August 2023, Musim Mas Group has proudly achieved 100% ISPO certification for its 17 upstream subsidiaries. IPM is also a key requirement for the voluntary Roundtable on Sustainable Palm Oil (RSPO) certification. Our 15 mills, integrated with plantations, are fully certified against the RSPO Principles and Criteria (P&C).
Embracing Nature’s Solutions for Sustainable Pest Management
Embracing a variety of beneficial plants is just one strategy we use to keep our oil palm plantations healthy and productive. By integrating these natural allies into our pest management systems, we reduce our reliance on chemical pesticides and take meaningful steps towards a greener, more sustainable future for palm oil cultivation.
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Reference:
[1] https://www.indonesiapalmoilfacts.com/g20/
[2] https://www.statista.com/statistics/1095648/indonesia-palm-oil-export-value/
[4] https://doi.org/10.1016/j.baae.2009.12.010
[5] https://www.mpoc.org.my/cassia-cobanensis-as-a-beneficial-plant-in-oil-palm-plantation/
[6] https://www.nparks.gov.sg/florafaunaweb/flora/2/5/2534
[7] https://www.nparks.gov.sg/florafaunaweb/flora/1/3/1312
[8] https://www.nparks.gov.sg/-/media/cuge/ebook/citygreen/cg15/cg15_10.pdf
[9] https://ksdae.menlhk.go.id/assets/publikasi/A_Guide_Book_of_Invasive_Plant_Species_in_Indonesia.pdf
[10] https://www.mpoc.org.my/cassia-cobanensis-as-a-beneficial-plant-in-oil-palm-plantation/
