Whether you're an amateur gardener or a professional, the first sight of black weevils (Otiorhynchus sulcatus) in your garden will send goosebumps down your spine, and for good reason. These pesky little pests can cause a lot of damage to your plants, so it's important to get rid of them as quickly as possible. In this article you will not only learn how you can fight black weevils with home remedies, but also how to get rid of their larvae. We'll give you useful tips and answer any questions you may have on the subject, giving you a complete guide to protecting your garden from the pests without the use of harmful chemicals.
What are black weevils & why are they a big threat to your plants
The thick-mouthed weevil (Otiorhynchus), also known as the broad-mouthed weevil, is a genus in the family of weevils (Curculionidae). It affects more than 100 different plant species, including ornamental shrubs and rhododendrons.
The black weevil grows to around 10 mm in size, is black with brown spots and has a structured surface. Its larvae also reach this size, have a brown head and are cream colored. The adult broad-mouthed weevils are usually brown or black and can grow up to 14 mm in size.
These pests are active at night, especially between April and October, and are well hidden during the day, making it unlikely that you will see them. They feed on the leaves of plants and their larvae feed on the roots. As a result, the plants can no longer absorb enough water and nutrients and die.
In addition, broad-mouthed weevils reproduce very easily and quickly. The females can lay up to 500 eggs in their short lifespan of two months. Therefore, it is important that you act immediately if you notice any signs of these pests.
Black weevil damage pattern:Adult broadmouth weevils leave a crescent-shaped hole along the edge of the leaf. This damage affects the appearance of the plant but is unlikely to have a serious impact on its health.
In contrast to the visible marks left by adult white weevils on plant leaves, those left by their larvae are more difficult to detect because they occur underground. And when the damage becomes visible on the surface, it is often irreversible.
What to do against black weevil & its larvae: Clean the garden & remove mulch
What helps against black weevils? One of the very first things you can do to protect your garden from white weevils is to keep it clean and remove all dead plants and weeds.
Second, since these pests love moist soil, you may need to remove mulch and compost piles. However, this should only be done if an infestation has been identified. However, mulching is an important part of retaining moisture in the plants.
Third, avoid overwatering your plants as water attracts pests. Also cut off low-lying leaves that touch the ground.
Mixed cultivation and crop rotation keep the pests away
What else helps against black weevils? Appropriate crop rotation and mixed culture are also advisable. Here's why!
If your garden is regularly plagued by plant diseases and frequent pest infestations, it is usually due to tired soil. To prevent this problem, the clever gardener relies on mixed crops and crop rotation. WhileIn mixed culture the plants interact with each otherand supporting each other as neighbors, crop rotation refers to the balanced exchange of positions of different garden plants after a certain period of time. These two methods ensure nutrient-rich soil, healthy plants and a lower risk of pests.
In addition, black weevils are attracted to certain plants. So if you grow the same thing in the same place year after year, there is a greater chance of an infestation. To prevent this, simply rotate your plants. Grow something else in the area where you had a white weevil infestation last year and the pests should disappear.
This is how you can fight black weevils with home remedies
There are various ways you can get rid of the annoying pests. You can fight black weevils chemically, but also with home remedies. Here we will take a closer look at the second option!
Setting up adhesive and pheromone traps
Fight thick-mouthed weevils with home remedies: Sticky traps are a simple and effective method for getting rid of adult broad-mouthed weevils. You can purchase them at most garden stores or make them yourself by coating cardboard with a sticky substance.
Place the black weevil trap near the plants affected by the pests and regularly check how many of them are caught. When the trap is full, throw it away and set up a new one.
You can also try using pheromone traps that are specifically designed to catch adult weevils. These traps lure the pests to them using a synthetic version of the white weevil's mating scent. They are a little more expensive, but worth the investment as they are very effective. However, remember that you will need to replace them regularly.
Fight black weevil larvae with nematodes
What natural remedies can you use against black weevils - nematodes are perfect for this! Nematodes are tiny parasitic worms that can be used to control a variety of pests, including white weevils. They penetrate the pest's body and release bacteria that kill it from the inside.
You can purchase nematodes for blackweed online or at some garden stores. Follow the instructions on the package on how to prepare and use it. Note that nematodes can only exploit in the warmer seasons – such as late spring or summer.
- Notice: Nematodes are harmless to humans, animals and plants, but they kill any insect they come into contact with, so you should use them with caution.
Make your own neem oil spray
How can you combat black weevils with home remedies? You can do this by making your own weevil spray! You only need three ingredients – neem oil, soap and water. Neem oil is very popular with gardeners because it is effective at killing many different types of pests, including the white weevil. It works by interrupting the pests' life cycle and preventing them from reproducing. You can apply neem oil to your garden using a spray bottle or watering can. That's how it works!
Neem oil against black weevils – this is how you make it:
- Mix one teaspoon of neem oil, one teaspoon of mild soap and 3 liters of water. Pour some of the mixture into a clean spray bottle and shake well to mix the ingredients thoroughly.
- Spray the solution onto the affected plants, making sure to cover both the top and bottom of the leaves.
- Repeat the process every few days until the infestation is gone.
Fighting pests in the garden without chemicals: tips, strategies and recipes that you can use immediatelycan be found here!
Fight black weevils with home remedies: coffee grounds come to the rescue
Coffee grounds against black weevils – Simply add them to the soil around the root neck of the plants every 3-4 weeks. However, we recommend that you combine it with some of the other pest control home remedies listed for better results!
Can you fight black aphids with home remedies?You can find out here!
Conclusion: Which is the best remedy against white weevils
Fighting black weevils with home remedies is a tedious task, but with a little effort you can get the problem under control and get rid of the pests forever. However, the best way to deal with black weevils is to take preventive measures and eliminate their food source. This means you will need to remove any weeds, dead or rotting plants. You should also ensure that your garden is clean and free of waste. If you have a compost bin, make sure it is covered so that the weevils cannot get to the food inside.
