What’s Eating My Roses? It Might Be These 5 Insects

Aphids are tiny (.25 inches or smaller) with light green, brown, pink, or yellow soft, pear-shaped bodies. They congregate in clusters on new rose growth. Curled leaves, deformed buds, and sooty mold indicate infestation.

Aphids are usually controlled within 2 weeks by their natural predators. You can encourage the presence of birds and beneficial bugs (ladybugs, parasitic wasps, lacewings, hoverflies) that prey on aphids by:

• Plant a diverse garden with attractive companion plants. Try yarrow, penstemon, and nepeta.
• Repelling aphids or masking the smell of roses to confuse them. Consider interplanting with basil, marigolds, rosemary, and alliums.
• Direct aphids away from roses by planting their favored plants as a trap. Try sunflowers, lupines, and nasturtium.

If you don’t wait to wait for natural predators to tackle your infestation (recommended as beneficial bugs provide long-term benefits to your garden):

• Use a strong direct spray from your hose to knock aphids to the ground, making sure to also target the undersides of leaves. They are slow and dumb and cannot crawl back up.
• Don’t mind a little ick-factor? Squishing them with gloved fingers works like a charm.
• If the infestation is severe and continues to occur, you might consider an insecticidal soap (use with caution only on cool evenings to prevent harm to your plants and beneficial bugs).

If you see leaves with transparent spots, tan or white blotches, or little left but the veins, carefully check the undersides of foliage for tiny, light green caterpillar-like larvae with tan-orange heads.

Sawfly infestations are prevented by:

• Companion planting for a diverse garden that attracts their natural enemies like frogs, birds, ladybugs, and predatory wasps.
• Including predator-friendly plants like sweet alyssum, thyme, fennel, and dill.
• Monitoring your roses early in the spring to catch infestations.

Manual removal is the most effective strategy for sawfly larvae. You can:

• Pluck them off and plunge them into a jar of soapy water.
• Remove the entire damaged leaf and dispose of it
• Use a high-pressure spray from your hose.
• Coat leaves with neem oil (use only as a last resort as neem may harm sawfly predators)

Thrips are difficult to see with the naked eye. If you spy signs of damage on a bloom:

• Open the petals and examine the interior to check for tiny fast-moving insects.
• Try shaking a bloom over a piece of white paper. Watch for them to fall out. They will look like teensy, rapidly moving brown or black specks.

• Thrips thrive in weeds and long grasses, so keep the area surrounding your roses clear of debris and prevent weeds with a thick layer of mulch.
• Create an environment friendly to their predators with companion planting.
• Use Blue Sticky traps to lure them away from your roses.

• Monitor roses early in the season.
• Cut off and dispose of damaged buds and foliage to prevent spread. Thrips live inside the buds, so this usually halts severe infestation.
• If thrip presence can’t be controlled via pruning of damage, consider treating with horticultural oil or a mycoinsecticide like Botanigard ES. Thrips are resistant to most common insecticides.

• Look for dull leaves that are mottled with yellow or brown.
• Check leaf undersides for tell-tale white webs.
• Rub a leaf with suspected infestation between your fingers. If it leaves a rusty residue, spider mites are the likely culprit.

• Look for dull leaves that are mottled with yellow or brown.
• Check leaf undersides for tell-tale white webs.
• Rub a leaf with suspected infestation between your fingers. If it leaves a rusty residue, spider mites are the likely culprit.

• Do not use insecticides. Spider mite problems often occur after insecticides are applied, usually because their natural enemies have been eliminated. Research shows that some insecticides actually encourage spider mite reproduction.
• Remove any leaves with visible webs.
• Hose off your rose thoroughly, making sure to hit the undersides of the leaves. Do this in the morning to allow roses to dry off, which will prevent fungal issues.
• If not controlled via previously listed measures, coat leaves in garlic extract or clove oil. Do this on cool days (90 ℉ or lower) to prevent heat-related damage.

Japanese Beetles are easy to see and catch in the act of munching on roses. If a large, shiny copper and green beetle is on your bloom (and you live in the Eastern or Midwestern United States), you’ve probably got Japanese Beetles

If Japanese beetles are a known problem in your area:

• Apply the natural bacteria Milky Spore in mid to late summer when grubs are active on the soil surface. This will kill grubs before they can mature into rose-eating beetles. However, it is known to be slow-acting and can take up to two years to be fully effective.
• Invite their predators (birds, small mammals, spiders, assassin bugs) in with a biodiverse, pesticide-free garden.
• Cover rosebushes with fine netting.

The only definitive way to tackle Japanese beetles is to remove them yourself.

• Shake rose blooms (or manually pluck beetles off and plunge) into a jar of soapy water in the early morning when they are sluggish.
• If you have too many roses for realistic manual removal, try spraying with a Bt (Bacillus thuringiensis) product. This soil bacteria, once consumed on leaf tissues, will halt feeding by the beetles.
• Treat with neem oil (this will require several applications) only on cool evenings to prevent harmful interaction with the sun that can damage plants.