How to Get Rid of Rose Chafer Beetles – Beginner’s Guide

American rose chafer (Macrodactylus subspinosus) is slim pale green to tan beetle, having long orange legs. Although these insects are native to North America, the distribution of them is fairly irregular. You can have a big problem with them, while a neighbor down the road has never seen them. They could be located anywhere around east of the Rockies.

The place where they are present, rose chafers could cause a lot of destruction, devouring the flowers and leaves of roses. They may eat the flowers entirely, while they could skeletonize foliage, leaving behind just the veins. Furthermore, despite its name, rose chafer is not just limited to roses. They consume other plants, such as Japanese lilacs, mountain ashes, daises, elderberries, grapes, hydrangeas, ivies, Boston ivy, spireas, brambles, apples, peonies, strawberries, irises, birches, hollyhocks, elms, cinquefoils, hawthorns, cabbages, and oaks.

The Lifecycle of Rose Chafer

The rose chafer’s life cycle starts in June when adult chafers lay eggs in sandy soil, preferably in sunny, dry spots, which are covered in weeds or grass, particularly lawns. These beetles lay eggs in less abundance in lawns, which comprise a significant proportion of clover. Also, they dislike and usually avoid shady spots and moist, rich soils.

Once done, tiny grubs hatch soon and burrow deeper into the soil. Unlike European chafer beetle grubs, rose chafer grubs do not harm turf grassroots. They grow all summer and then, go deep into the soil for resting for winter. In the spring, grubs come out to the surface and eat for some time and then, turn into pupae for a few weeks before they emerge in June from the soil for starting the life cycle over.

As female chafer beetles lay eggs in sandy soil, you will find a large number of beetles in gardens having sandy soil. However, these insects can fly a distance for feeding.

The damage done to plants is primarily cosmetic. This is because plants recover when rose chafer beetles restrict feeding and eventually die, near June’s end. However, the flower loss and the remaining sight of plants’ leaves with just the veins make most gardeners fight them. So, if you spot lots of chewed up flowers and leaves in June, it means an invasion of rose chafer has taken place.

At the same time, if you grow grapes, then rose chafers are more about just cosmetic damage. Generally, grapes bloom at that time when these beetles emerge and the hungry ones like to eat grape buds and flowers. As a result, you have to bear the loss of your grape crop.

How to Get Rid of Rose Chafer Beetles

For controlling rose chafers, gardeners can handpick the beetles and drop them into a container filled with soapy water. Or just shake the plant lightly, it dislodges lots of these beetles. If plants are sturdy, you can use a hand vacuum and empty the dirt cup having beetles into soapy water.

You can employ typical garden insecticides like Sevin to kill these beetles. However, you need to re-apply it after every 10-14 days and heavy rain. You can also use systemic insecticides, which are available in rose care products. These insecticides work but the chafers need to bit the plant before they are poisoned. So, this process involves some damage.

While using pesticides, you have to read and follow the instructions on the label on how to mix and apply them exactly. Ensure that the insects you like to kill and the plants you like to protect are mentioned on the product. Different plants or different insects have different mixing instructions and application.

While rose chafers are heavy, you can cover plants using row cover material. Securely anchor it to the ground so that beetles do not crawl beneath it. For grapes, row covers do not work as they need to have calls from pollinators to bear fruits. Also, pesticides may kill pollinators but are the only option if the number of beetles is high.

Some studies carried out by the USDA have shown that spraying kaolin clay-based products on your grapevines help to repel chafer beetles. You can spray this product on shrubs and trees being eaten by these beetles. However, it gives a whitewashed appearance to the sprayed plants.

How to Control Rose Chafer in Long Term

For long-term control, people need to work on reducing the number of larvae or the egg-laying ability of the chafer. To discourage these beetles, you may like to redo the law by putting a cover of a 6-inch quality sand-free topsoil. Then, re-sow using a mixture of clover and lawn grasses. Also, you can try planting tall perennials, trees, and shrubs for shading the soil.

The beetle’s larval stage is a white C-shaped grub, who lives in the soil. People find it difficult for distinguishing the grubs of June beetles from Japanese beetles. The Japanese beetles live in lawns under similar conditions. Nematodes are specially designed for controlling all kinds of white grub, including rose chafer beetle. Effective nematodes are available in various garden centers.

There is just a single generation of rose chafer beetle every year. After 3-6 weeks of destruction, the infestation will stop suddenly as it started. Generally, affected plants recuperate quickly, produce new leaves and soon, you won’t see the destruction anymore. However, rose chafers may have ruined that fruits and blooms of the summer already by then. Check out this video to watch how to control rose chafer using solar lighting.