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Problem
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Description
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Solution
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Aphids
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Very small insects, usually green or black, mostly on the underside of leaves and on new growth.
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Thoroughly hose aphids off foliage; you can also apply insecticide soaps to control aphids.
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Japanese Beetles & Rose Chafers
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Hard-shelled insects which eat various parts of the rose plant.
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Pick the insects off individually, or use a biological control called "milky spore disease" (Bp), which is commercially available.
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Leaf Cutter Bees
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Circles or ovals neatly cut out of the leaves, wilted stems indicate tunnel inside.
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Seal canes with white glue after pruning to prevent the insects from tunneling the stems.
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Rose Borers
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Insects which enter the cane and feed on the pith inside. Canes turn black and wilt.
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Use a multipurpose spray to get ride of the fly that lay eggs; seal canes after pruning to prevent further borer entry.
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Spider Mites
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Leaves turn yellow, dry out, and in severe cases, fall off the plant. Tiny webs on the underside of the leaves.
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Hose the undersides of leaves with a fine spray of water for 3 days in a row to disrupt breeding cycle. An insecticidal soap will also work well.
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Thrips
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Buds turn brown and do not open, or are distorted. Thrips are feeding on plant juices.
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Control with a pesticide spray. Direct spray into the opening buds. Or, use a systemic rose care product.
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Blackspot
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Leaves have black spots, and will fall off if fungus is not treated.
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Pick off isolated leaves; control with a fungicide spray. Provide good air circulation; water when foliage will be dry before dusk.
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Canker Dieback
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Rose canes turn dark brown or black and die progressively down the stem.
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Always remove the damaged part of the cane, then follow a regular spray or dust program. Avoid injury to the canes and use a sealer after pruning.
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Chlorosis
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Usually not a serious problem. Leaves turn yellow due to a lack of iron, nitrogen, manganese or magnesium, or a salt buildup.
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Add chelated iron to the soil, or in severe cases, spray iron sulfate on foliage. Apply 1/4 cup epsom salts in one gallon of water to the soil during the season.
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Crown Gall
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Tumor-like swellings appear near the bud union, plants lose their vigor and die.
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Cut off galls with a sharp knife disinfected with alcohol. Paint pruned area with a mild bleach solution. Burn diseased portions of the plant.
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Mildew
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Leaves are distorted and covered with fine white fungus growth.
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Control with a fungicide spray that controls mildew and leafspot disease. Provide good air circulation.
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Yellow Leaves
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Leaves turn yellow and may fall off. Could be caused by poor drainage.
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Bad weather can slow chlorophyll production, so wait it out. Add sand or gypsum to improve drainage.
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