Robusta coffee berries ripening in the coffee forests of Poomaale Collective

Robusta coffee plant gets its name from the fact that it is a more resilient coffee variety. It can withstand extreme climatic conditions and resist external stresses. It is robust! 

Arabica and Robusta coffee plants are different in this very sense. Though arabica coffee is more popular worldwide due to its flavour notes, the arabica coffee plant is very delicate and needs a lot of care. This adds to the already high cost of arabica coffee. Robusta coffee plants are stronger and can hold their ground on their own with minimal external care. 

But even the most robust of species in nature are prone to attacks, especially when they’re grown with minimal intervention and into the wild. Wild forest-friendly coffee can be grown sustainably. Though minimal, intervention at the right places at the right time is the key. This includes the natural methods by which pests of robusta coffee plants can be managed without causing harm to them and the environment. 

5 Major Pests of Robusta Coffee Plants

1. Coffee Cherry Borer

Coffee berry borers are one of the most damaging pests affecting coffee plants, including Robusta coffee plants. These small beetles can lay their eggs inside the coffee cherries, and the resulting larvae feed on the coffee beans inside. This feeding activity can cause significant damage to the beans, reducing both quality and yield.

In Robusta coffee plants, coffee berry borers can cause damage to the fruit, leading to reduced bean size and quality. The coffee beans may also become discoloured, which can reduce their value. In severe infestations, the coffee cherries may drop prematurely from the tree, leading to reduced yield.

2. Shoot Stem Borer

Shoot stem borers are insects that can cause damage to the stems and shoots of Robusta coffee plants, leading to reduced growth and yield. These borers, which are the larvae of moths, tunnel into the stems and shoots of the plant and feed on the inner tissue, causing damage to the vascular system of the plant.

The damage caused by shoot stem borers can weaken the coffee plant, making it more susceptible to other pests and diseases. In severe infestations, the stems and shoots of the coffee plant may become distorted or die back, leading to reduced yield and quality.

3. Mealybugs

Mealybugs are small, soft-bodied insects that can cause damage to Robusta coffee plants. They feed by sucking sap from the plant’s leaves, stems, and cherries, which can weaken the plant and reduce its growth and yield.

The feeding activity of mealybugs can cause the leaves of Robusta coffee plants to turn yellow and curl up, and the plant may become stunted. Mealybugs can also excrete honeydew, a sweet, sticky substance that can attract ants and other pests to the coffee plant. In addition, the honeydew can promote the growth of sooty mould, which can cover the leaves and cherries of the plant, reducing photosynthesis and causing further damage.

4. Ants

One of the main ways in which ants can affect robusta coffee plants is by protecting and farming other pests, such as aphids, mealybugs, and scale insects, which can feed on the coffee plant and cause damage. Ants are attracted to the sweet, sticky secretions that these pests produce, and this will protect them from predators and parasites.

Ants can also cause damage to Robusta coffee plants directly. They may tunnel into the soil around the roots of the plant, causing damage to the root system and reducing the plant’s ability to absorb water and nutrients. Ants may also build nests on the coffee plant, which can lead to physical damage to the plant’s branches and leaves.

5. Root-knot nematodes

Root-knot nematodes are microscopic worms that can cause damage to the roots of Robusta coffee plants. These nematodes enter the roots of the plant and feed on the cells, causing the roots to become swollen and knotted. This can lead to reduced growth and yield of the plant, as well as increased susceptibility to other pests and diseases.

The damage caused by root-knot nematodes can also lead to secondary infections by other pathogens. The nematodes create entry points for other soil-borne pathogens, such as fungi and bacteria, to enter the plant and cause additional damage.

Natural Pest Control Methods for Robusta Coffee Plants

The best way to manage a coffee forest is by doing your job and letting nature do its own for the most part. A coffee forest ecosystem is full of pests that can damage your crop, but it is also full of predators, natural enemies of these pests. ‘Beneficial bugs’ like ladybugs, lacewings, parasitic wasps, millipede assassin bugs, etc feed on aphids and mealybugs. Intercropping coffee with other plants, such as legumes or herbs, can help attract beneficial insects and repel pests. Rotating coffee crops with non-host crops can help reduce pest populations by interrupting their life cycle and reducing their food source.

Birds play a major role in natural pest management in a coffee forest. Firstly, they’re naturally attracted to the ripening coffee berries and feed end up feeding on its pulp. During this, they also feed on the pests that are harming the coffee berries. Birds eat the berries too, but it does more good than harm as they help in dispersing the seeds across and help the coffee forest expand naturally. Birds and trees/plants share a mutually beneficial relationship.

Another important creature in the pest management cycle of a coffee forest is the snake.

The presence of snakes reveals a lot about the health of a coffee plantation/forest. As coffee is a shade-grown crop, coffee plantations become a natural home to snakes as the sunlight-to-shade ratio is ideal for regulating their body temperature. Snakes prey on several creatures in a coffee forest, including many of the pests that harm the coffee plant, thereby keeping the pest population in check.

Planting certain plants alongside Robusta coffee plants can help repel pests and attract beneficial insects. For example, planting marigolds can help repel nematodes, while planting mint can help repel aphids. Polycultural practices like these not only help in managing pests but also improve the biodiversity of the coffee forest.

Robusta coffee grows wild at our Poomaale Estate in Coorg. It grows under a forest canopy of the Western Ghats and is supported by the wetland ecosystems as well as the rich biodiversity. The coffee growth relies on monsoon alone and manual maintenance. Despite minimal inputs, we received an abundant robusta harvest this spring, which only goes to show that adapting to natural processes and cycles is a sustainable and healthy way of growing what we consume.