Are you facing an infestation of weevils in your garden?
You are not alone as they are the leading cause of damage in gardens—making them one of the most frustrating pests to deal with.
By nature, weevils are non-flying beetles with a characteristic snout-like mouth. It’s estimated that there are over 97000 types on the planet.
These different weevil types can feed on over 100 species of plants. Unfortunately, they’re almost impossible to detect, and homeowners often never see them until it’s too late.
Control measures must take place year-round if you want to keep your garden beautiful and healthy.
We offer you some helpful insights and remedies you will find handy in eliminating these destructive bugs. Let’s get going.
The Different Types of Weevils
Common weevil types you are likely to find in your home or garden fall under the list below:
1. Rice Weevil (Sitophilus oryzae)
The rice weevil is tiny, measuring about 1/16 inches long, and is easily identifiable by its four yellow, reddish spots found at the back.
The adult rice weevil has a life span of five years and can fly. Their larvae are minuscule, while the pupae are white with long snouts like the adults.
A female rice weevil can lay up to 400 eggs in its lifetime.
2. Black Vine Weevil (Otiorrhynchus sulcatus)
Also referred to as the texas weevil, the Black vine weevils are characterized by destructive larvae that feed on a wide range of ornamental plants. They are typically black and covered in fine hair.
They love to feed on common ornamentals such as the hemlock, yew, and rhododendron. Apart from chewing vines and leaves, the bugs eat away the roots and stems of the affected plant leading to its demise.
Their larva overwinter in the soil after partial growth and emerge later as adults in late spring.
3. Bean Weevil ( Acanthoscelides obtectus)
The bean weevil is a grain feeder that typically feeds on soybeans, chickpea, and lentils. It grows 3-4mm long, taking a circular shape with long legs.
Their larvas are white and grub-like with reduced legs. You know you have these destructive bugs in your garden when you encounter seeds with their entry or exit holes.
The exit holes are rounder and more prominent than the dot-like entry holes.
4. Wheat Weevil (Sitophilus granarius)
Wheat weevil is also known as the grain weevil, a common grain pest in gardens. It has a penchant for attacking stored grains leading to substantial losses.
Their larvae typically consume the inside of the stored grains.
Adult wheat weevils are reddish-brown with no distinguishing marks. They are 3-5mm long and have an elongated snout and a chewing mouth part.
Wheat weevils will vary in size depending on the grain they are attacking. For example, ones attacking sorghum are smaller than those attacking corn.
5. Rose Weevil (Pantomorus cervinus)
You can spot a rose weevil by its red-black hard body. Their head and mouthparts are elongated with visible antennae and long black legs.
If not controlled in time, rose weevils can cause massive damage to your rose flowers.
The adults typically chew and puncture flower stems and buds, leading to wilting.
The receptacles of your rose flower are not spared either by the larvae of the pesky bugs.
11 Ways To Get Rid of Weevils In Your Garden
Weevils can be pretty challenging to remove from the soil and plants once they establish themselves.
The best approach is denying them a favorable habitat, as we highlight below.
1. Practise Crop Rotation
An easy technique you can employ to get rid of weevil infestation in your garden is crop rotation.
You may be experiencing repeated infestation because of a particular crop you keep growing year in year out in the same spot.
Plants susceptible to weevils include common leafy vegetables such as cabbage, spinach, and fruit-bearing plants such as tomatoes, onions, beets, and radishes.
Instead of growing these plants in your garden for consecutive years, rotate them with plants not susceptible to weevil infestation, such as chamomile, chives, and castor beans. In addition, you could use nitrogen-fixing plants to help improve soil fertility.
When rotating crops, dig over the soil to expose the larvae and eggs of weevils to the scorching sun or predators.
2. Use Safe Predators
One of the safest and natural ways to fight off weevils is nurturing their predators. These predators do not pose any risk themselves and help control the overwhelming populations of these troublesome insects.
Common predators for weevils include chickens, warblers, frogs, ladybugs, praying mantises, and birds.
However, some birds, such as mockingbirds, could be more trouble than worth.
3. Biological Control
Get rid of weevils in the garden through biological control. For the record, it’s the best alternative to chemical treatment.
Biological control of weevils involves using beneficial organisms such as nematodes to eliminate the irritating bugs. Nematodes are tiny circular worms that don’t grow beyond one inch.
They are beneficial because they feed on soil-inhabiting larvae and pupae of insects such as the root weevil. However, they also have the potential of parasitizing above-ground insects.
Introduce nematodes in your garden from early spring through fall. The microscopic organisms are harmless to other beneficial insects, pets, and humans.
You can search around your locality for garden centers that sell them.
4. Control Weeds In The Garden
Some weeds attract and provide a favorite habitat to weevils. Common ones include Dandelion, Docks, Capeweed, and Sorrels that act as host plants.
Controlling these weed types in your garden helps you get rid of weevils as well. Uproot these weeds in their nascent growth stages as they become difficult to eradicate once established.
5. Safeguard Your Plants With Burlap
If you are a wildlife enthusiast hurting weevils might put you off completely. And if this is something you can’t overcome, you want to use burlap to protect your plants against weevil infestation.
Most weevils get trapped in the material during the day when looking for a place to hide. Once a sufficient number of weevils have been trapped, collect them and find a place where you can dispose of them safely.
Shake off the burlap bag and use it again.
6. Keep Your Garden Clean To Minimise Their Hiding Places
One of the easy ways to keep the weevils off your garden is by ensuring your garden is clean of plant debris and stagnant water.
The thing with weevils, especially the adult ones, is that they love to hide in crevices and dirt such as mulch and compost.
Dispose of dead plants, weeds, and piles of leaves and twigs. Regularly prune your plants to prevent the extra foliage from harboring the bugs.
Interestingly, weevils also get attracted to water. Open water containers or water puddles around your plants are a sure way to attract them.
Always harvest water in tanks away from your garden.
7. Deter the Weevils With Bay Leaves
Some plants, especially strong-smelling herbs, are very effective at repelling weevils. A typical herb plant you want to use is the bay leaf plant.
Like most herbs, bay leaves have a bitter taste and pungent odor. Key components of the herb are essential oils and a compound known as Eucalyptol, which, according to scientific research, can repel insects.
You can prepare a natural insecticide for your garden using the step-by-step guide below.
Natural Insecticide For Weevils
1. Pluck some fresh bay leaves and dry them.
2. Take some camphor and crush it till it takes a fine powdery form.
3. Add the crushed camphor to a small amount of neem oil and mix well.
4. Place the dried bay leaves in a clay bowl.
5. Coat the leaves with the mixture prepared earlier.
6. Burn off the leaves.
7. The smoke keeps away weevils, mosquitos, and a host of other troublesome insects without being harmful in any way whatsoever.
8. Use Pheromone Traps
Pheromones are chemical substances secreted by the same member species triggering specific responses.
You can rid weevils off your garden by luring them into pheromone traps. For example, if you have a banana plantation, you could attract the banana weevil through a pheromone trap baited with the pheromone specific to the weevil.
Ideally, you should set up the traps quite close to large clusters of these insects.
9. Get Rid Of The Weevils Manually
If everything else fails, the only option to get rid of these bugs is to remove them manually.
Weevils are nocturnal creatures by nature. That is why you see them in small numbers during the day,
If you want to take them out in large numbers, you need to venture out at night.
- Locate the weevils by heading into your garden with a flashlight at night.
- Arm yourself with a medium-sized piece of cardboard and a container of soapy water.
- Place the cardboard under the infested plants.
- Hold the stem slightly above the soil surface and shake it vigorously.
- The mini earthquake will make the weevils fall of the plant.
- Ensure you wear gloves for scooping the remaining adult insects, eggs, and larvae.
- Dump them in the soapy water container and dispose of them.
10. Build Barriers In your Garden
You can keep weevils out of your garden using barriers such as row covers. They help prevent their spread from one row of plants to another.
You could also purchase weatherproof fabric and PVC piping from your local store for the project.
11. Use Sticky Tape
Another idea to protect your plants from weevils is wrapping them with yellow sticky tape.
Insects are attracted by the yellow color and sticky substance of the tape. This method works very well against a range of problematic insects such as weevils, bugs, aphids, and thrips.
Weevils are destructive bugs that slowly nibble away at your garden, food crops, and plantation.
Prevention is the best cure against them as they become increasingly difficult to eliminate once established.
The methods highlighted above are based on prevention and will surely help you in controlling their population.
Job Kiniale is a certified crop scientist and gardening enthusiast with a passion to help beginning gardeners navigate their newfound hobby. Let’s talk about plants, backyard ideas, and general gardening advice. Outside work, Job loves spending time with family.