11 Rose Bush Pests: Identification, Treatment & Prevention
Garden roses are hardy and long-lasting, but they’re also prone to attack from certain pests each season. In this article, gardening expert and rose enthusiast Danielle Sherwood identifies the most common pests you might find plaguing your rose bushes, along with how to prevent and treat them.
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When spring arrives and we begin to anticipate the opening of our first rosebuds, we soon realize we’re not the only ones excited for spring! The rose pests have been waiting too, and they’ve announced their presence via holes in the foliage, sticky webs on leaf undersides, or maybe whole colonies of visible creepy-crawlies on new growth.
Unfortunately, there are many different pests that can plague our garden-grown roses. While some are easy to identify, others will require a little more detective work.
So, if you see signs of pest damage (or the pests themselves!), we can help. Let’s look at the most common pests for rose bushes and how to identify, treat, and prevent them.
Aphids
Aphids are often the first pest to make an appearance in early spring. These small, soft- bodied insects cluster around the soft new growth on your roses. They feed by piercing the plant and sucking its sugary juices.
Aphid infestations are easy to spot. You will see groups of light green, pear-shaped insects huddled together, sometimes covering whole buds of your rosebush. Other signs of aphid damage are curled leaves, disfigured buds, or a sticky, black substance on the foliage.
Such a large number of bugs on your rose can be alarming, but aphid infestations usually go away on their own via control from their natural predators in a couple weeks. If you don’t want to wait it out, there are some ways you can fight them on your own.
How to Identify
Usually light green, brown or pink, with pear shaped bodies, aphids are small and gather in clusters on the ends of new growth. Curled leaves, deformed buds, and sticky foliage indicate infestation.
How to Prevent
Attract natural predators and repel aphids by creating a diverse garden with companion plants like basil, catnip, rosemary, and alliums. Consider planting trap plants aphids favor, like lupines, nasturtium, or sunflowers to direct them away from your roses.
How to Treat
Get rid of aphids with a strong, direct spray from your hose, knocking them to the ground. Get the undersides of leaves as well. Predatory insects will take care of the rest as they wake up in the next couple weeks. If the infestation is too severe, consider an insecticidal soap (use with caution to prevent harm to beneficial bugs).
Sawfly Larvae
Also called Rose Slugs, sawfly larvae look like little green caterpillars. They are under ½ inch long, with light green bodies and tan heads. They chew on the undersides of leaves, creating tan blotches and a transparent look to the leaf.
Some rose slugs fully skeletonize the leaves, leaving only the veins. Fortunately, the damage is aesthetic and doesn’t harm the health of your rose.
Adult sawflies are in the wasp family. When mature, the female will lay her eggs on the edges of leaves. There is only one generation of sawflies per year, usually spotted in May and June.
How to Identify
If you have white to tan blotches or transparent circles on your rose leaves, look for small green caterpillar-like larvae with brown-orange heads, especially on the undersides.
How to Prevent
Encourage sawfly predators like birds, ladybugs, and lacewings to make your garden home by providing a water source and a variety of attractive companion plants (you’ll have the best luck with plants native to your region). Monitor your roses in early spring to catch infestations quickly.
How to Treat
Manual removal is the most effective. Pluck them off and plunge into a jar of soapy water. You can also use a high-pressure spray from your hose. Use insecticidal soap or Neem oil as a last resort to reduce impact on sawfly enemies.
Thrips
If you see brown streaks on the petals of your open rose blooms, take a close look inside. Are there fast moving tiny winged insects at the base of the petals? Chances are, you’ve got thrips.
Thrips have pale bodies and dark wings, but they are so small (1mm or less), you aren’t likely to notice. Signs of thrip damage include petals with brown edges or streaks on light colored roses, and deformed buds that never open..
Thrips pierce foliage and buds of roses and extract sap from the bush. A particularly aggressive species, called chili thrips, also attack new foliage, leaving bronze streaks on the leaves. With a thrip infestation, it’s also common to see your rose begin to drop its flowers.
How to Identify
Thrips live inside buds and at the base of petals. They are difficult to see with the naked eye, so peek into a bloom and check for tiny fast-moving bugs inside the petals. This combined with brown streaks, red spots, and darkened outer petals indicates the presence of thrips.
How to Prevent
Thrips prefer to live in weeds and long grasses, so keep the area surrounding your roses clear of debris and mulch well. Blue Sticky traps can be effective in luring them away from your roses.
How to Treat
Cut off and dispose of any damaged buds and foliage. Thrips live inside the buds, so this will usually control infestation. If you need to take a further step, kill them off with a fungus-based insecticide.
Spider Mites
Spider mites are microscopic, 8 legged bugs. Not actually spiders, they earned their name from the sticky white webbing they leave on your roses.
These tiny pests suck the chlorophyll from leaves, resulting in small yellow spots. Eventually, entire leaves will turn dull and brown. Spider mites frequently stick to the undersides of leaves, so if you see brown foliage, flip it over to check for webs.
Spider mites love hot, drought-stressed plants. Keep your roses healthy and hydrated as the first line of defense.
How to Identify
Look for dull, brown or yellow leaves. Check the undersides for sticky white webs. Rub a leaf with suspected infestation between your fingers. If it leaves a rusty residue, you likely have spider mites.
How to Prevent
Spider mites like hot, dry conditions and thirsty roses. Make sure your roses are well-watered (one time deep watering of 2-5 gallons a week).
How to Treat
Thoroughly hose off your rose, making sure to hit the undersides of the leaves (do this in the morning so foliage can dry out during the day). Spider mites will not be able to crawl back up. If extreme, apply a miticide like Grower’s Ally Spider Mite Control.
Cane Borers
Cane Borers on roses are usually the larvae of several different types of insects, like wasps and beetles. They aren’t necessarily gardening enemies, often maturing into insects that prey on rose foes like aphids.
Borer damage shows up in the form of brown, dried out, dying canes. Look for a hole in the center of the cane where the borer tunneled down to lay its eggs. You may also see swelling or blotches on the dead cane.
Cane borers aren’t usually fatal to roses, but sometimes the hole can go all the way to the crown of the bush, causing further damage. Inspect brown or dead canes right away to minimize impact.
How to Identify
Check brown, dying, previously pruned canes for a hole tunneled into the center. You may sometimes see blotchy patches or irregular tunnels on damaged canes.
How to Prevent
When pruning large canes, seal off the cut with wood or non-toxic clear glue. This is only necessary if borers are active in your area, as rose canes seal themselves with time. Borers prefer sickly plants, so maintain your roses’ overall health to make them less attractive.
How to Treat
Cut back damaged canes a couple inches at a time until you reach green healthy growth and a solid white center.
Japanese Beetles
Japanese Beetles are metallic copper and green pests that feast on rose blooms and foliage. They don’t discriminate, and commonly attack other plants. They have sturdy bodies and bright copper heads, with white hairs near their legs.
Native to Japan, they are now prevalent in the eastern US and moving west. They begin their life cycle as grubs in the soil, and show up as mature rose-eating beetles in early summer.
Pesticides are ineffective in controlling Japanese beetles, but that doesn’t mean you have to let them eat your roses. A bacteria control called Milky Spore works over time to kill grubs in the soil, while manual removal controls adult populations.
How to Identify
Japanese beetles are easy to catch in the act of eating your roses. They are shiny green and copper and about ½ inches long. You may also see munched on or skeletonized leaves.
How to Prevent
If Japanese beetles are a problem in your area, try applying Milky Spore in mid to late summer when grubs are active on the soil surface. This natural bacteria will kill off the grubs before they mature.
How to Treat
The only surefire way to tackle Japanese beetles is to remove them yourself. Though tedious, it will save your blooms. In the early morning when they are slow and sleepy, pluck or shake them off into a jar of soapy water and dispose of it. If you have too many roses to make this feasible, consider spraying with, a Bt (bacterium Bacillus thuringiensis) product.
Budworms
Budworms are a type of caterpillar ranging in size from .5 to 2 inches long. Commonly known as tobacco budworms, they are usually light green, but sometimes brown or pinkish in color. They come from moths that lay their eggs in your rose’s flowers. When hatched, they begin chomping through the blooms.
Budworms are most active at dusk and at night, eating oval shaped holes in your blooms or devouring them completely. They often leave behind globs of black droppings on damaged petals.
Many budworm predators like spiders, birds, and lacewings will keep them in check if you avoid pesticides. However, you can give nature a hand and stop these pests from eating your roses with a few key steps.
How to Identify
Budworms look like small green caterpillars with striped sides and brown heads. They leave holes and black droppings on rose blooms. Check for them at nightfall.
How to Prevent
Encourage biodiversity by planting a variety of plants in mixed borders, rather than roses in their own garden section. This makes infestation less likely and attracts natural predators.
How to Treat
Handpick budworms when you see them (check at dusk!), and remove infested buds promptly. For potted roses, change soil to remove grubs. Spray a Bt product designed for caterpillars like Monterey Bt directly on active, feeding adults.
Scale Insects
Rose scale doesn’t look like an insect at all! You’ll notice colonies of white or brown bumps on your rose stems that look more like a fungal infection. The bumps are actually immobile scale insects, covered with a waxy shell.
Scale insects pierce rose canes and feed on the juices, resulting in weakened plants. Fortunately, healthy roses can tolerate light rose scale infestations and they will clear up on their own (often with the help of birds and ladybugs).
However, if you see spindly, stunted growth and decreased bloom production, you may want to address these little armored bugs yourself.
How to Identify
Rose Scale looks like white, light gray, or brownish flat scales up and down your rose canes. Underneath the waxy armor are little sap-sucking insects.
How to Prevent
Always replace potting soil from infected roses in containers. Dispose of any pruned plant debris away from your garden to avoid reinfestation. If your roses are weakened by scale every year, consider a preventative application of Neem oil.
How to Treat
Prune off heavily infected canes. If scale is light, spray with rubbing alcohol and gently remove with a toothbrush or Q-tip.
Rose Weevils
Rose weevils, also called Rose Curculios, are a type of snout beetle that feeds on rose blooms. They prefer yellow, white, and occasionally pink roses. Symptoms include hole-punched rosebuds that never open, blooms with ragged, chewed petals, and gouged bent stems.
These garden pests are about ¼ inch long, and dark red with long black snouts. They lay their eggs inside rosebuds, hatching in late spring to feed on blooms at night.
The best methods of control target both the larvae and adult stages of the weevil. If they’re particularly prevalent in your area, consider planting roses in a darker color palette.
How to Identify
Rose weevils are reddish black, about ¼ inch long, with downward curving snouts. Infected rosebuds may look hole-punched and fail to open. Stems below the bud may be broken or bent.
How to Prevent
Rose weevils, their eggs and larvae are a popular snack for many garden predators like wrens, bluebirds, frogs, and praying mantises. Encourage these predators to visit your garden by planting native plants and setting up water sources. You can also use beneficial nematodes in the soil to tackle the grubs before they mature.
How to Treat
Shake the weevils off your plants into a bucket of soapy water and dispose of them. Prune off damaged buds and stems.
Deer
Unlike many deer-resistant perennial plants, roses are like candy to these four-legged herbivores. If the tops of your roses appear lopped off with ragged stems, chances are they’ve fallen victim to deer.
Deer like to feed in the late evening or early morning, so look out for them at these times to verify your culprit. They love young, tender growth, often mowing newly planted roses nearly to the ground!
There are many products on the market to deter deer, including sprays, alarms, and enclosures. Experienced rural gardeners know that the only certain way to keep hungry deer from roses is to keep them behind sturdy fencing.
How to Identify
Rose bushes eaten by deer often appear ragged and lopped off at the top. Sometimes, they will be munched down to a few inches from the ground. Catch deer at nighttime or early morning.
How to Prevent
Keep treasured roses behind 6-8 foot fences. Deer are less likely to jump over if they can’t see what’s on the other side, so choose a solid material like wood or brick.
How to Treat
Try to scare deer off by chasing them away or making loud noises. Try deer-repellent sprays and granules. Natural options like sprinkling human hair around your roses or coating with predator urine have variable results.
Rabbits
Rabbits are another cute herbivore that love a rose buffet. Rabbit damage will be low to the ground, usually a few inches to a foot up your rose. Unlike deer, rabbits leave smooth cuts at a clean 45 degree angle, making their handiwork easy to identify.
Other signs rabbits are in your yard include large holes where they’ve tunneled into the ground, and piles of brown or green pellet droppings.
Much rabbit damage occurs in winter when there is little else available to eat, so plan on adding protection to your roses as part of your overwintering preparations. Prevent rabbits from entering your garden by erecting a fence, or consider putting your roses in pots or tall (4 ft.) raised beds.
How to Identify
Clean cuts at a 45 degree angle on the bottom 2 feet of your rose, as well as holes and droppings in the garden indicate rabbits.
How to Prevent
Prevent their entry with a fence. Bury it at least 18 inches into the ground to prevent rabbits burrowing under it. Protect individual roses with 4 foot chicken wire cages. Alternatively, plant roses in tall pots or raised beds.
How to Treat
Don’t disturb or remove nesting rabbits. Wait for them to mature and leave your garden. To protect unfenced plants, try making a spray with crushed red peppers and garlic, or consider getting a dog to chase adult rabbits away!
Final Thoughts
Most pesky bugs and critters plaguing your roses are a critical piece of the ecosystem, and can never be fully eliminated. A bit of tolerance goes a long way toward making growing roses a more pleasurable experience for all!
However, invasive species (like the Japanese beetle) provide little benefit and need your intervention to remain under control. If this occurs, research methods with the least impact on your garden and its helpful creatures first, taking severe action only when those fail. Your roses will benefit from your balanced approach!
