Sri Lanka Weevil: All You Need to Know – A Friendly Guide

The Sri Lanka weevil, scientifically known as Myllocerus undecimpustulatus undatus, is a plant pest that is rapidly gaining attention due to its vast range of host plants and destructive tendencies. Originating in Sri Lanka, this weevil has since spread across India, Pakistan, and even made its way to the United States. Notoriously known for being a pest to over 20 different crops, it is essential for gardeners, landscapers, and farmers alike to recognize the impact and potential damage these insects can cause.

You may be wondering what sets the Sri Lanka weevil apart from other weevils and plant pests. For one, their distinctive gray and black color makes them easily identifiable among other leaf-chewing beetles. Additionally, they are known to attack more than 70 different ornamental and fruit-producing plants, leaving their mark on some of our favorite foliage and food sources.

In this article, we will dive deeper into the intricacies of the Sri Lanka weevil and its impact on the environment and the agricultural industry. By understanding this pest and recognizing the telltale signs of their presence, you can take effective steps to protect your precious plants and crops from their destructive appetite.

Sri Lanka Weevil Overview

Appearance and Habitat

The Sri Lanka weevil, or Myllocerus undecimpustulatus undatus, is a small plant pest with a varied range of hosts. They appear grey and black and usually grow to around 1/8 inch long. As a native of Sri Lanka, they thrive in warm climates and primarily target ornamental and fruit-producing plants in their habitat. Some examples include over 70 different types of plants often found in South Florida.

Distribution

Originally from Sri Lanka, these weevils spread to other countries like India and Pakistan. In the United States, they have been identified in Citrus plants in areas like Pompano Beach, Florida. Due to their adaptability, they can become pests to over 20 different crops, making them a concern for farmers and gardeners alike. To protect your plants from these pests, it’s essential to be aware of their distribution and take preventative measures when needed.

Lifecycle

Eggs

The Sri Lankan weevil begins its life as an egg, which is laid by the female weevil on the leaves or stems of host plants. These eggs are typically oval and small in size. After a short period of time, the eggs hatch and the larvae emerge, ready to feed on the host plant.

Larvae

The larvae of the Sri Lankan weevil are cream-colored, legless grubs with a distinct brown head capsule. They tend to feed on the roots and leaves of various plants, causing significant damage. Larvae often tunnel into the plant tissue, leading to further destruction. This feeding behavior not only affects the health of the plant but also its appearance.

Growth

During development, the larvae of the Sri Lankan weevil go through several molting stages, progressing towards adulthood. Once they reach the final larval stage, they enter the soil and form a protective cell made of soil particles before pupating. Following this stage, the fully-grown adult weevil emerges from the soil, ready to reproduce and continue its lifecycle.

Overall, understanding the lifecycle of the Sri Lankan weevil is vital to better comprehend its behavior, as well as aid in the development of effective control methods for this invasive pest. By learning about the stages of its development, you can take steps to protect your plants and prevent further infestations.

Impact of Sri Lanka Weevil

On Home Gardens

Sri Lanka weevils can cause significant damage to your home garden. They are known to feed on a variety of plants, leading to defoliation and stunted growth. Be cautious of damaged leaves, as this could be a sign of their presence.

On Citrus Plants

These weevils particularly affect citrus plants, feeding on the leaves and sometimes the roots. They have a tendency to chew irregular notches, which can lead to yellowing leaves and eventually, the death of the plant.

On Palm Trees

Palm trees are also a favorite target for Sri Lanka weevils. They cause harm by feeding on the leaves, often leading to discolored foliage and fronds with a tattered appearance. Regular inspection and prompt attention can help minimize damage.

On Lychee Trees

Lychee trees suffer similar damage when infested with Sri Lanka weevils. These pests consume the leaves, causing visible puncture marks, and can impact the tree’s overall health. Stay alert for any signs of infestation to maintain the well-being of your lychee trees.

Detection and Control

Damage Identification

To identify a Sri Lanka weevil infestation, look for notched leaves on a wide range of host plants. The adult weevils cause excessive leaf damage, while the larvae feed on roots and cause plant weakening. The weevil has a unique tendency to drop to the ground and pretend to be dead when disturbed, making it difficult to detect¹.

Preventive Measures

You can take several preventive measures to reduce the risk of infestation:

• Regularly inspect your plants for signs of damaged leaves.
• Keep the area around your plants clean and free of debris.
• Hand-pick weevils when spotted, or shake branches over an open container to catch them².
• Encourage natural enemies such as birds and lizards to visit your garden.

Pesticide Use

If the infestation is severe, using pesticides might be necessary. However, always follow the label instructions to ensure safe and effective use. Here are some guidelines for using pesticides:

• Opt for targeted, less toxic pesticides that specifically address weevil infestations.
• Apply pesticides during early morning or late evening, when the weevils are less active and less likely to drop to the ground.
• Reapply pesticides according to the label’s recommended schedule to achieve effective control³.

Remember to monitor the affected plants closely after treatment to ensure the infestation is under control. Keep your garden well-maintained and adopt a friendly approach to keep this pest at bay.

Additional Resources and Information

You might be interested in further expanding your knowledge about the Sri Lankan weevil. For a detailed overview of its biology and host interactions, the University of Florida’s Entomology Department provides a comprehensive resource.

If you’re looking for academic or research articles on the Sri Lankan weevil, EDIS offers an informative publication. This can help you gain deeper insights into its impact on various crops and its geographical spread over time.

To organize information on the Sri Lankan weevil, consider using a comparison table. This allows you to easily visualize characteristics, such as:

Lastly, remember to approach your research with a friendly and open-minded attitude. This will make the learning process more enjoyable and productive. Remember to verify information when possible, and avoid making exaggerated or false claims about the Sri Lankan weevil.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Yellow Headed Ravenous Weevil

Need Help ID These Bugs?
Location: Indialantic, Florida
April 4, 2012 8:53 am
Can Somebody please help me identify these bugs? I saw the white bug on pine needle and the small one that looks like a fly on this yellow flower.
Signature: ADubin

Dear ADubin,
Your white insect is an invasive exotic species commonly called the Sri Lanka Weevil or Yellow Headed Ravenous Weevil, Myllocerus undecimpustulatus, and we identified it on BugGuide where it is stated:  “in FL, recorded from 55 host plant spp., from palms to roadside weeds, including citrus.”  This article from the University of Florida has some additional information, however, pine is not mentioned as a host plant.  Here is another online article from the Florida Department of Agriculture and Conservation.  Invasive species that pose a threat to agriculture or native plants are often well documented on the internet.  We will try to identify your other submission and we will post it separately.     

Letter 2 – Sri Lanka Weevil

Subject: Bug eating my lemon tree leaves.
Location: South Florida
February 12, 2015 1:13 pm
I have this bug/beetle eating my little outdoor lemon tree leaves around the edges and is there a treatment for them?
I hope you can help.
Signature: Joe cocchario

Dear Joe,
This is a Sri Lanka Weevil, Myllocerus undecimpustulatus.  According to BugGuide:  “native to Sri Lanka, adventive and established in so. FL.”  BugGuide also notes:  “in FL, recorded from 55 host plant spp., from palms to roadside weeds, including citrus.”  According to Featured Creatures:  “Leaf-feeding adults damage the foliage of ornamental plants, fruit trees, and vegetables, whereas the larvae injure root systems. Due to its feeding habits, the Sri Lankan weevil could negatively affect subtropical and tropical fruit, ornamental, and vegetable industries here in Florida. The possible impact to the horticulture industry in nurseries, landscape services, and horticultural retailers could reach billions of dollars based on the value they generate in Florida (Kachatryan and Hodges 2012). Extension agents and Master Gardener volunteers around the state have received requests from homeowners for information on the control of this weevil. Botanical gardens and plant nurseries have reported damage due to chewing injury and require effective control measures.”

Update:  It seems Joe submitted a photo previously posted to our site, so now we cannot be certain that the insect eating his lemon tree leaves is actually a Sri Lanka Weevil.

Letter 3 – Yellow Headed Ravenous Weevil

Subject: albino bug
Location: Melbourne, FL
August 6, 2012 9:32 pm
NEVER seen one of these before, but he flew away like a ladybug by slipping a couple of dark-ish wings out the back of his spotted shell and politely rising in a delicate drunken line and then buzzing off. He visited me on 8-5-2012 in Central Florida near the Atlantic Coast. For perspective, he’s sitting on the lip of a 1/2 liter water bottle.
Signature: GAboyinFL

Dear GAboyinFL,
This is an invasive, exotic species, the Yellow Headed Ravenous Weevil or Sri Lanka Weevil, Myllocerus undecimpustulatus.  According to BugGuide, in southern Florida where it has been established, it is ” recorded from 55 host plant spp., from palms to roadside weeds, including citrus.”