One of the most common problems of growing plants is pests. Some of them are easy to control, but there are some that require a special approach. One of those will be discussed in this post.
To get rid of the weevil on Coral Bells, pick the most active adults with your hands at night. Also, spray heuchera with a systemic insecticide and water it with an aqueous solution of beneficial nematodes to kill the grubs.
This is a short description of the most effective approach, I will tell you all the steps in more detail later on. Also, be sure to check out the article How to Grow Coral Bells Successfully in the Garden.
Pest description
Adult weevil and grub.
The weevil (Otiorhynchus sulcatus) is a rather secretive insect. It comes out to feed only at night, thus eliminating the possibility of being eaten by birds.
As a result, you will not see it unless you go into the garden with a flashlight at night.
This pest has an oblong body about half an inch long. The color is black to dark gray or brown. It has six paws that allow it to move quickly.
Adults prefer the leaves of Coral Bells, while grubs feed on roots. One female can lay about a thousand eggs. Once hatched, they are able to completely destroy the entire heuchera root system.
This pest affects a number of ornamental plants. But the most serious damage it does to agriculture.
Symptoms
Heuchera leaves are damaged by an adult weevil.
The first sign of weevils is a gnawed leaf edge. After a while, it becomes dry and brown. The leaf looks notched afterward.
Over time, the leaves get more and more damaged, but you won’t notice the pest because, as I mentioned earlier, it only comes out in the dark.
A sign of the presence of weevil larvae is the slow growth of the heuchera. Then it is possible that the stem will lose its upright position and bend to the ground.
Also, the leaves will brown on the edge or droop along with the leaf petioles. This is because the roots are gone and the plant has nowhere to take up water.
Heuchera roots are damaged by a weevil grub.
How to deal with adult weevils?
The first thing you can do is to collect the weevil by hand. Wear gloves and take a flashlight. Go out in the evening when it is already dark and examine your heucheras.
If you see black beetles, collect them in a jar with a lid or other airtight container. Then destroy them all, if you leave at least one alive the population will quickly resume.
For potted Coral Bells, you need to use bug tape. Simply wrap the tape around the top of the pot from the outside. Since weevils can’t fly, they will stick to the tape and can easily be picked up.
The most effective way to kill adult beetles is to use systemic and contact insecticides. But because these products are not safe for pets, they are not readily available everywhere.
Unfortunately, organic pesticides such as neem oil do not work against weevils.
How to deal with weevil grubs?
If your heucheras leaves are damaged by the weevil, it is likely that females have already laid eggs around the roots. It is only a matter of time before the larvae hatch and destroy the roots.
In this case, you should not wait for Coral Bells to suffer but use beneficial nematodes. You can find suppliers on the market who offer products that work well against not only weevil larvae but also many other bugs.
Prepare an aqueous solution with the nematodes as labeled. Apply only in warm weather. Water all your heucheras abundantly with this solution. The nematodes will then enter the soil and kill the grubs.
If the roots are already damaged, dig up the plant and clean the dirt from the roots. Wash the wounds and plant the bush in a new location. Collect all grubs and destroy them.
How to prevent the spread of the vine weevil
The first thing to do to prevent weevils from getting into your yard is to buy only healthy plants. This is not only true for Coral Bells.
Before you buy, inspect the plant carefully for insect damage to the leaves. Pull the plant out of its pot and examine the roots to see if there are larvae. If there is even the slightest trace of pests, look for another supplier.
Preventively use weevil traps. Even if they are not in your garden, traps can catch the first ones that come in.
Also, if there is the slightest suspicion that weevils are present, don’t wait for the population to increase but use beneficial nematodes wherever possible.
What to do with damaged Heuchera?
If the weevils have damaged only the leaves, Coral Bells will recover after some time. To ease the recovery process, water the plant with a liquid multipurpose fertilizer. Repeat this after some time.
Keep to the proper growing conditions and after a while, it will look as if nothing has happened.
If the grubs have damaged the roots, dig out the bush and remove the dirt. Wash the roots with water and treat the wounds with an aqueous solution of hydrogen peroxide.
Plant it in the clean substrate and move it to full shade. Wait for the plant to fully recover before planting it in the garden.
If the heuchera has fallen to the side and the grubs have eaten all the roots you need to re-root it. Divide the bush into several pieces, the larger the pieces the faster they will root.
Plunge the pieces into sterile potting soil, use pots about 5 inches across. Put them in a dark place. Once a full root system is formed, Coral Bells can be planted in a permanent location.
Read more: What Bugs Eat Heucheras?