Most of the root weevils will have an average length of ¼ to ½ inch. They have a hard body, broad snout, and elbowed antennae. Root weevils also do not have the capacity to fly. They crawl to feed on their host plants, but generally speaking, they are slow movers. Most, if not all, have a black body with elytra or leathery wings on the outer part of their body. Some of the most popular species that fall under this group include black vine weevil, strawberry root weevil, and obscure root weevil.
Root Weevil’s Habitat
Adult root weevils usually appear out of their pupation stage from May to June. It takes a maximum of 45 days before they will lay their eggs. Their eggs are laid on leaf litter or the soil. When they are in their larval stage, they will feed on the roots of their host plant. On the other hand, once they transition into adults, they will devour the leaves and the stems, among other parts that are above the ground. When you disturb the host plant, the adult root weevils will fall on the ground since they cannot fly.
During hot or dry weather, root weevils can migrate inside the house, especially in areas that are moist. The good thing is that while they can be invasive, they will not cause any harm when they are indoors and when they do not live near host plants.
Identifying Root Weevil’s Damage
Trees, flowers, shrubs, and vines are amongst the most common hosts for root weevils, although this will largely depend on their specific type. Black vine weevils, for instance, are common in blueberries, grapes, laurels, azaleas, and rhododendrons. Strawberry root weevils, on the other hand, are common pests in strawberries and raspberries.
Although there are different species of root weevils, they are similar in terms of their signs and symptoms, which will include the following:
- The larvae will feed on the root, which is why it will be the one to show the first signs of damage. This will result to root pruning. If the population is high, this can make the plant weak and it will soon die.
- The larvae, when it matures, will travel away from the root ad crawl on the top of the plant. At this stage, it can also lead to girdling. It will chew the stems or veins of the host plant, which can inhibit the flow of nutrients.
- Leaf notching, on the other hand, will be the sign of the presence of adult root weevils. When the notching is only light to moderate, which is the case most of the time, it will not cause too much problem to the plant.
Results of Infestation
In most instances, the injury is light and most of the damages are only cosmetic. However, in cases of severe infestation, especially in the roots, it can be a huge problem. This can inhibit the supply of the nutrients that are needed by the plant to grow. Because of this, the host will most likely wilt and eventually, it will die. For commercial growers, the failure to address the problem as soon as possible will lead to an economic loss.
How to Get Rid of Root Weevil
Natural and Organic Solutions
For a successful way to control and eliminate root weevils, the following are some of the solutions that are promising:
- Handpicking weevils, especially the adult ones, can be one of the first solutions. This may require a lot of effort on your end, especially because you have to do it at night. Be sure to have a flashlight handy so that you can easily see the adult flies. You can also shake the plant. Take them out manually from the host plant or from the ground and throw in a bucket of soapy water. This will instantly kill them.
- You can also consider using sticky barriers on the ground or the stems pf the host plant. this will prevent the larvae from crawling on the top. The weevils will stick on it and other won’t even dare go up. A waterproof and polyethylene tape will do the job.
- Habitat modification will also be a good step to eliminate the root weevils. Removing excess mulches and prevention of overwatering are some of the ways to deter their presence. This will prevent having excessive moisture, and hence, make the environment less favorable for their survival. It is also important to have proper drainage to be sure that water does not get stuck on the surface.
- It will also be good to resort to the use of biological control. This is good because it kills only the root weevils and other destructive pests. It does not affect the beneficial insects. Among others, entomopathogenic nematodes are some of the best. These colorless and unsegmented roundworms will release bacteria that will instantly kill the host.
- Root weevils are common not only in the garden, but even within the household. With this, to get rid of them, one thing that you can do is to prevent moisture. Sealing openings will also be a good way to prevent their entry. Vacuuming is another solution that can bring excellent outcomes.
- Make sure to maintain the garden. Keep it clean and free from plant debris and leaf litter, which can encourage the growth of root weevils.
Chemical control can be effective, but you need to do it with caution. They contain toxic ingredients, which can harm even beneficial insects. Depending on where you live, check the chemicals that relevant authorities allow. Also, be sure to read the label and learn its proper application, not only for effectiveness, but for your safety as well.
Most of the products are foliar insecticides. Some of their most common active ingredients and brand names include the following: chlorpyrifos (Pageant), bifenthrin (Talstar), acephate (Orthene), and bendiocarb (Turcam).