It is that time of year again when farmers are going in and amateur and professional gardeners alike are having to brush up on pests. One of these pests is the Black Vine Weevil (Otiorhynchus sulcatus), which is from the Curculionidae family.
Controlling them in natural ways is covered in this article. If there are signs of garden weevils, go on the offensive immediately to get rid of them.
By using natural options, you’ll ensure that your crops don’t contain harmful chemicals when harvested. It will also ensure that you do no additional damage to the land or surrounding plants.
What follows are the various natural and organic ways to get rid of vine weevils and their larvae.
1. Remove the Mulch
As the black weevil prefers heavily moist soil, the removal of mulch and other compost materials and items may be necessary.
However, only do this after detecting an infestation. Mulching is a critical component of keeping moisture in plants that require it in many cases.
2. Diatomaceous Earth
This treatment, composed of fossilized remains, has a powder-like consistency.
Diatomaceous earth is mildly abrasive. It will break through the protective layers of the exoskeleton and absorb the waxy cuticle of weevils, ants, and other insects. It will kill them within 48 hours of application.
Overall, DE is a good natural product to manage many insects in and out of your garden and house. Sprinkle it around garden beds, pots, and the roots of infested plants.
3. Natural Predators
Invite in your natural enemies, or at the very least, don’t kick them out. Frogs, birds, toads, and shrews all feed on these insects and/or their grubs.
Allowing these predators to remain in your garden or even introducing some of them can help control the population of vine weevils.
Insects such as the ground beetle and rove beetles also feed on certain insect pests.
Therefore, acquire thorough knowledge of all the harmful insects residing on your farm. This will ensure that you kill the bad ones and save the ones that will work for you.
4. Pick Them Off
The most time-consuming but easiest home remedy is to pick them off.
Knock off these critters by putting cardboard, umbrellas, or newspaper at the base of plants and shaking the plant to release the weevils.
Next, put them in a sealable bag for disposal. Alternatively, drop them in hot, soapy water to kill them. Pure boiling water will also work.
Stay alert by picking any off by hand that you see and removing the grubs from the ground. Remember, in indoor or greenhouse planting environments, you will not be immune to these pests.
Checking under plants, in garden soil, and even in pots that present a cool location for vine weevils to rest during the day can reveal them.
5. Repellent Plants
Planting certain insect-repellent plants in your garden can help deter pests.
Plants that vine weevils dislike include lavender, mint, and lemon balm. If possible, mix these among your crops to help control or prevent infestations.
6. Sticky Traps
A sticky barrier is an excellent trap that you can place at the base of plants. It traps adults, after which you can dispose of them away from the garden.
Of course, this will only take out the adult weevils. The larvae should be stopped in another way.
Also, if these traps become laden down with insects quickly, you might need to employ another eradication method.
Moreover, there are a wide array of options with barriers. You can buy them online or make homemade vine weevil traps using various items like vaseline or non-drying glue.
However, sticky traps do need regular inspection. This is to ensure that heavy rains, hot temperatures, and other outliers have not damaged them.
Replacing the barriers when they are full will also ensure they continue to work efficiently.
7. Beneficial Nematodes
You can purchase beneficial nematodes to control grubs in your garden. Besides, you can even add them to the soil in pots to get rid of vine weevil grubs.
These microscopic organisms, which are non-segmented roundworms, can help control vine weevil larvae by parasitizing them. Death starts within 48 hours of application.
8. Limit Excess Watering
The moisture in the soil feeding your garden is one of the most critical components of a good season. Excessive moisture may facilitate vine weevil and other pest larvae, while not enough can, of course, damage crops.
During excessive rain, limit additional water to the garden. Also, the removal of mulches and such that would trap moisture at a higher level than needed in the soil should occur.
There should be a balance when it comes to watering your garden.
Safe Commercial Black Vine Weevil Insecticides
If you’re wondering how to get rid of vine weevils organically without having to whip up some homemade concoction, there are safe commercial options available.
All these products are OMRI-listed or WSDA-certified for use in organic farming.
This product is made of Beauveria bassiana, a naturally occurring fungus that infests pests when applied to their exterior.
It causes white muscadine disease. The fungus spores thrive off the nutrients in the pests’ bodies, eventually killing them.
It just needs to come into contact with the insect to go to work. BalEnce can be applied throughout the growing season, up until harvest.
This product is a natural vine weevil killer and an all-round insecticide.
AzaGuard is a heavy-lifting botanical insecticide and nematicide combination that claims to control over 300 insect species.
The main ingredient in this product, azadirachtin, is derived from the neem tree.
This ingredient is a molting and growth disruptor. It impedes ecdysone production, which is necessary to move the grubs into full adult stages. Consequently, they will later die.
This spray kills vine weevils. However, it is not harmful to humans or pets that may come into contact with it during its application to gardens.
This version of Beauveria bassiana is a liquid formula that you can apply to your garden. It can help control weevils.
Additionally, Mycotrol is useful in all stages of the life cycle of the pest to help control it before new adults mature to above-ground status and chew on your plants.
12. BioCeres WP
This is another multi-functional product containing Beauveria bassiana. BioCeres WP can be used on all types of weevils, including root, rice, and black vine weevil grubs.
It also works great against beetles and borers. It will kill these pests in 7 to 14 days.
Vine Weevil Life Cycle
The lifecycle is one generation per growing season. They will overwinter as nearly mature larvae and come out in the spring.
Hatching occurs in about ten days, after which they burrow and start eating in gardens.
Getting rid of them and how quickly you act will determine your ability to stop infestations early.
The signs of an infestation are pretty easy to spot. There will be notches chewed into plants and white or light brown eggs in the dirt around the base of plants.
Additionally, signs of damage to roots may include wilting and dying plants.
These small insects are slate gray and measure less than an inch, averaging ¾ of an inch. They cannot fly and spend the night chewing on a large variety of plants.
The small, approximately ½ inch-long, white, c-shaped grubs of the black weevil tunnel through roots in their feeding frenzy. This can cause large-scale damage to your plants.
These slate-grey, unassuming black pests are a sign of trouble ahead in your garden. At the very first signs of trouble, start with a black vine weevil control plan.
Remember, the insects you see on the plants are not the worst of it. The larvae still in the moist soil will be doing the most damage when this insect is present.
But as you can see, there are a host of natural options you can employ to help control these critters. With some due diligence, quick action, and monitoring, you can minimize the risk to your garden!