Because winged euonymus is essentially immune to scale, the traditional nemesis of the euonymus family, it has few pest problems.
Foliage Curls, Turns Yellow Can Be Caused By Aphids
Aphids are soft-bodied, pear-shaped, green, brown, black, or pinkish insects a little bigger than the head of a pin. They cluster on tender new growth and suck sap from leaves and stems, causing foliage to curl, pucker, and yellow, and reducing the plant's vigor. Ants, attracted by the aphids' honeydew secretions, wander over the plants and protect the pests from natural enemies. Check leaf undersides for small groups of aphids. For light infestations, spray the undersides of the winged euonymus leaves vigorously with water three times, once every other day, in the early morning. In cases of heavy infestation spray visible aphids with insecticidal soap every 2 to 3 days. As a last resort, spray them with pyrethrum spray. For more information see the file on Controlling Aphids
Leaves Discolored Often Caused By Thrips
Adult thrips are tiny, slender insects, 1/25 inch long, variously colored pale yellowish, black or brown. They rasp leaves and petals, sucking sap from the injury. Leaf surfaces become flecked and whitened and the tips wither, curl up and die. Leaf undersides are spotted with tiny black specks of excrement. Since thrips quickly burrow out of sight deep between petals, early identification and control is essential. Set out yellow sticky traps about 4 weeks after last frost as early warning devices. As soon as you spot thrips on the trap, spray insecticidal soap on nearby winged euonymus shrubs every three days for two weeks.
Tumor-like Swellings On Trunk Or Branches Is Usually Crown Gall
A bacterium infects shrubs through wounds and stimulates cells to form tumorlike swellings (galls) with irregular rough surfaces. To avoid crown gall, avoid planting winged euonymus shrubs with suspicious galls on their roots or stems. Destroy heavily infected plants. If only a few galls are present, cut off and destroy the affected stems. Sterilize pruning tools afterward in 70% denatured alcohol to avoid spreading the disease
Sunken Spots On Leaves Can Be Anthracnose
This fungal disease forms distinct lesions on leaves, which appear as moist, sunken spots with fruiting bodies in the center. Leaf spots may run together, resembling a blotch or blight. The dead areas follow the veins or are bounded by larger veins. Sometimes the tips of branches die back to several inches below the buds. Pustules containing pinkish spores appear. Dieback and defoliation may occur in severe cases. Gather and destroy infected fallen leaves. Prune away diseased branches. Maintain plant vigor by feeding and watering well, especially during droughts. Spray with a copper fungicide such as Bordeaux mixture. For more information see the file on Controlling Fungal Disease
Leaves Spotted; Turn Brown Can Be Caused By Leaf Spot
Leaf spot diseases caused by various fungi occasionally attack winged euonymus shrubs, causing yellow, brown or black dead blotches on their leaves. Often these spots come together to form larger patches of dead tissue. Gathering and destroying fallen leaves usually controls this disease. If needed, spray the vine with a copper fungicide. For more information see the file on Controlling Fungal Disease
Leaves Covered With White Powder Is Powdery Mildew
Powdery mildew caused by fungi attacks winged euonymus once in a while, especially in the southern states and the Pacific coast. Spray affected shrubs thoroughly with wettable sulfur once or twice at weekly intervals starting as soon as you see the whitish fungus coating the leaves. Collect and discard all aboveground refuse in the fall. For more information see the file on Controlling Fungal Disease
Foliage Burned Can Be Caused By Dogs
Dog urine may discolor winged euonymus foliage and even kill branches. Spraying foliage with an antitranspirant gives some protection. Screen the plants or spray them with an aerosol pet repellant. For more information see the file on Dogs and Cats