Banana root borer facts for kids

The banana root borer (scientific name: Cosmopolites sordidus) is a type of weevil. Weevils are small beetles with a long snout. This particular weevil is also called the banana borer or banana weevil. It's known as a major pest because it causes a lot of damage to banana plants. You can find it almost anywhere in the world where bananas are grown. In fact, it is considered the most serious insect pest for banana farming.

What Does It Look Like?

The adult banana root borer is about 11 mm (3⁄8 in) long. It looks shiny and can be greyish-black or dark brown. Unlike some other beetles, its body part behind the head (called the thorax) is smooth. Each of its legs has a special hook-like claw. This helps the insect hold onto plants very well.

The young banana root borer, called a larva, is plump and whitish. It has a reddish-brown head. The larva's body has breathing holes called spiracles. The eighth body segment has a large spiracle, while the others are small. The last two segments are joined together, forming a flat shape.

The pupa is the stage between larva and adult. It looks a bit uneven. You can see the developing wings and legs through its outer skin.

Where Do They Live?

The banana root borer likely first appeared in southeastern Asia and Indonesia. But now, it lives all over the world. You can find it in every place where bananas are grown. This includes southwestern Europe, southern Asia, Africa, Australia, and many parts of North, Central, and South America. In the United States, it is mostly found in Florida.

These borers can easily travel from one place to another. This often happens when people move banana roots or plant parts that contain the larvae.

How Do They Live?

Banana root borers mostly eat different types of Musa plants. This is the plant family that includes bananas. They especially like plantains and East African Highland bananas. They are drawn to these plants by special smells that come from them, especially from damaged roots.

Sometimes, they might eat other plants like Manila hemp, sugarcane, or yams. But they usually only do this if they cannot find any banana plants.

The female adult borer lays her eggs one by one. She places them between the leaf and the stem, or near the base of the plant's root (called the corm). About six days later, the eggs hatch. The young larvae then start to dig into the stem or root. Their digging makes the plant weak. This can cause the plant to fall over easily, especially in windy weather.

The entire life cycle, from egg to adult, takes about 30 to 40 days. The larval stage, when they do most of the damage, lasts about 15 to 20 days.

In southeastern Asia, there is a beetle called Plaesius javanus. This beetle is a natural enemy of the banana root borer. It eats the borer's eggs, larvae, pupae, and even the adult borers. This helpful beetle has been brought to other places where the banana root borer lives. This is a way to use biological pest control to help manage the borer problem.

What Damage Do They Cause?

When the banana root borers tunnel inside the plant, they cause several problems.

• They make the stem weak. This means the plant can easily fall over, especially in storms.
• The plant has trouble taking in enough nutrients from the soil.
• This leads to less fruit and smaller harvests for farmers.
• New banana plants often do not grow well if borers are present. The damage gets worse over time.

Adult borers are active at night. They are not very good at flying and do not lay many eggs. This means they do not spread very far on their own.

Farmers can try different ways to control these pests:

• Planting roots that are free of insects can help for a few years.
• Removing and destroying old plant parts after harvest can also reduce the number of borers. This helps increase the amount of bananas grown.
• Another idea is to use special smells called pheromones to attract the adult borers. These can then be caught in traps.

See also

In Spanish: Gorgojo negro del banano para niños