Gardeners delight in the spring when the garden bursts into life.
Fresh foliage to welcome in the new season, then anticipation builds for the colorful blossoming of rose bushes.
The excitement’s quickly diminished when you find holes in the leaves of your rose bush.
As excited as we are to welcome the start of a new gardening season, so too are a bunch of garden bad guys that see your roses as a buffet.
When you find holes in your rose leaves, it’s probable there are insects getting an early start.
Read on to find the clues that identify what’s eating holes in your rose leaves and the fixes to put an end to it.
What is eating my rose leaves?
The most damaging rose leaf-eating pests are Rose Slugs (the larvae of sawflies), Japanese Beetles, and Fuller Rose Beetles (Rose Weevils). Each can quickly defoliate a rose bush. Leaf-cutter bees create half-moon cuts from leaf edges.
The leaf-cutter bee is under an inch in size. These are solitary bees so there’s no risk of a colony of bees nesting in your shrub.
The damage they cause is only aesthetic. Your rose bush will flower as normal.
You can tell the leaf-cutter bee is visiting your rose bush when you notice half circles being eaten from the leaf edges. The diameters can be up to three-quarters of inch.
Despite the cuts looking like something eaten a part of the leaf, it’s not been eaten. It’s been taken from the plant to be used as nesting material. You’re doing the pollinator kingdom a favor by letting the bees do their thing.
The leaves from rose shrubs are a preferred nesting material for these bees. Other bush types they prefer are the leaves from are the Virginia Creeper, and the Lilac bush.
It won’t harm your roses. You’ll still get plenty of blooms. If the leaf damage does become prominent to the extent you feel you need to stop it cutting discs from the leaves, cover it with netting.
Don’t use insecticides as these are beneficial insects.
Rose slugs aren’t slugs. They’re the larvae of sawflies that feed on the underside of leaves. They are heavy feeders.
In their early life stages, the holes they make are so tiny they only like brown spots on the leaves of roses. White spots on roses are different. Those are likely teeny aphids or mealybugs.
Once rose slugs mature, they reach about a half-inch to three-quarters of an inch in length. They’re green-bodied with a yellowish-orange head that look very much like a caterpillar.
In their adult larvae stage, that’s when they cause real damage when they can eat right through a leaf.
A heavy infestation of rose slugs can strip your plant bare of the leaves.
These are nighttime feeders that are most active in early spring to late summer. The best control method is to knock them off the plant either by hand or hosing the leaves early each morning.
Unlike caterpillars that can be taken care of with Bacillus thuringiensis (Bt), it doesn’t have an effect on rose slugs, since they’re neither a caterpillar nor a slug. They’re the larvae of the sawfly.
If you do need to use an insecticide, horticultural oil and insecticidal soaps work as contact insecticides killing on contact. Not by ingestion.
Fuller rose beetles
The fuller rose beetle can do severe damage to roses. They eat the leaves and the flowers. They’re all female and deposit eggs in the soil so even if you do remove all of them, a new family will emerge next season.
Eggs hatch in the soil and the larvae start to feed on the plants roots for up to 8-months, eventually emerging as fuller rose beetles around spring the following year.
Adult rose beetles are brown and wingless. They’re nighttime feeders but by day, they hide on the underside of leaves. Not in the soil.
The damage they cause is distinctive. On the leaves they are eating, the only part that will remain untouched will be the thick large vein running down the center of the leaf their feeding on.
The severity of the damage this pest causes will require remedial action to revive a dying rose. It might be heavily damaged this year, but it can survive heavy defoliation.
These can eat multiple leaves, and the flowers. Where they’ve been eating, around the holes will be tearing with ragged edges.
To stop these eating your rose leaves, remove them by hand or hose them off with a jet spray of water. Take advantage of their inability to take flight by skirt pruning your rose bush.
Prune the lower part of the rose bush so that adults emerging from the soil can’t climb onto the leaves. For the main trunks, use sticky traps to catch the adults before they get a chance to climb onto the plant.
The Japanese beetle tends to be active in early summer. It’s easily recognized by its copper-colored back with a blueish-green head. It’s about a half-inch in size and can be handpicked off your roses and the leaves.
If left unchecked, they cause significant damage by skeletonizing the leaves. You’ll be left with a real ugly-looking rose bush.
Given these are easy to spot, and they don’t bite, you can just pick them off. Go at them in early morning on in the late evening.
They’re most active during the day.
Early morning and late evening is when they get docile making them easier to pick off or knock the leaves or flowers and they’ll fall right off.
When not to remove the Japanese beetle
The only time you don’t want to remove this bug is when there are white spots on the backs of a Japanese beetle. These don’t have spots on their shells.
When there are white dots, it’s more likely the eggs of a tachinid fly that’s using the beetle as a host. The tachinid fly is a beneficial insect that will eventually kill the Japanese beetle.
There are different species of tachinid flies, but they’re all parasitoids, meaning they’ll kill off some type of garden pest, which can include the ravenous geranium budworm, tomato hornworm, or even the half-inch sized shield bugs that attack most fruiting plants.
If a Japanese beetle has white spots glued to its back, keep it around. You want those eggs to hatch because they will be doing you a huge favor in the garden.
Frequently Asked Questions related to what eats rose leaves
What animals eat rose leaves?
Deer, squirrels, and rabbits will chew on all parts of rose bushes, not just the leaves. If you’re seeing chunks eaten from your leaves, buds and canes, especially on tender growth, it’s likely caused by deer browsing, or rabbits and squirrels gnawing your plants.
What can be put on rose leaves to stop insects eating them?
The answer is neem oil. It can be effective at controlling numerous bad guys that eat holes in your rose leaves without having a harmful effect on beneficial insects like ladybugs. To prevent leaf burn, apply it when it’s cooler, either early morning or late evening. Not in the hottest heat of the afternoon sun.
Marcel runs the place around here. He has a deep passion for houseplants & gardening and is constantly on the lookout for yet another special plant to add to his arsenal of houseplants, succulents & cacti.
Marcel is also the founder of Iseli International Commerce, a sole proprietorship company that publishes a variety of websites and online magazines.