Brown, Dead Patches on Leaves Caused by Leaf Scorch
Drought conditions can cause ivy leaves to turn brown during the summer. In the winter, harsh sun and drying winds cause similar symptoms. Ivy growing on a south-facing wall or near pavement may also be scorched by reflected light and heat. To prevent leaf scorch, make sure plants get enough water. Cover those exposed to sun or wind with evergreen boughs in winter. Spraying the leaves with an anti-transpirant spray may also help by reducing water loss from the leaves.
Leaves Yellowed and Curled by Aphids
Aphids, also called "plant lice," are soft-bodied, pear-shaped sucking insects about the size of the head of a pin. They sometimes cluster in large masses on tender new leaves and growing tips of ivy. Their feeding retards plant growth, causing the leaves to curl and turn yellow. Ants, attracted by the aphids' honeydew secretions, wander over the plants and protect them from natural predators.
Check stem tips and leaf undersides for small groups of aphids. If only a limited area is affected, pinch off the aphid infested stems and/or leaves and put them in a plastic bag for the trash. Spray light infestations over a wider area vigorously with water 3 times, once every other day, in the early morning or spray visible aphids with an insecticidal soap product as directed on its label. If aphids persist, spray them with a pyrethrin or pyrethrum based insecticide product as per instructions on the package label. Do not fertilize the ivy. Consider what may be causing it stress and correct those conditions. For more information see the files on Controlling Aphids
Leaves Stippled Yellow or Red by Spider Mites
Spider mites are tiny spider-like pests about the size of a grain of black pepper. They may be red, black, brown, or yellowish-white. Mites feed by sucking juices from plant tissues, removing chlorophyll. They also inject toxins into leaves, discoloring and distorting them. Foliage of mite-infested plants becomes stippled with small yellow dots or red spots, and sometimes fine-webbing is visible. Eventually, the infested foliage turns gray and dry.
Mites attack plants that are under stress and are a particular problem to ivy grown indoors as a houseplant. They attack ivy outdoors in very dry weather or in areas where frequent use of broad spectrum insecticides has killed off beneficial insects which usually control them. Spray infested ivy in the early morning with a forceful stream of water every other day for 3 days, to knock the mites from the leaves. If they persist, spray mites with insecticidal soap or a product containing neem according to product label instructions. For more information see the file on Controlling Mites
Small Bumps on Stems and Leaves Indicate Scale
The first sign of a scale attack is yellowing of ivy foliage, followed by leaf drop, reduced growth, and stunting. Heavy infestations may kill young, individual plants, but do not usually destroy a large established ivy planting. Some species of scale excrete honeydew, which attracts ants and encourages the growth of sooty mold on leaf surfaces. To spot the scale look for their rounded waxy shells, which protect them as they suck plant sap from stems and leaves. The bumps may be white, yellow, or brown to black, and are about 1/10 to 2/5 inch in diameter.
Spray infested plants or patches of ivy with light horticultural oil to smother the adults within their shells and any eggs that may be present. For more information see the file on Controlling Scale
Cottony Masses on Leaves and Stems Means Mealybugs
Ivy infested with mealybugs looks unsightly and does not grow well. Mealybugs are real pests of indoor or greenhouse potted ivy. The insects gather in cottony white masses on the roots, stems, and leaves, sucking sap and reducing plant vigor. They secrete honeydew as they feed, which attracts ants and encourages mold growth. Mealybugs are 1/5 to 1/3 inch long, oval, flattened, covered with white waxy powder and adorned with short, soft spines around their sides. The telltale cottony tufts on ivy leaves and stems are their egg sacs.
Check plants before purchasing for evidence of mealybugs. Sometimes a forceful spray of water from the hose (or the water faucet for indoor ivy) is all it takes to discourage a mealybug attack. Spraying either a light horticultural oil or insecticidal soap product will also control most infestations. Read and follow label instructions. For more information see the file on Controlling Mealy Bugs
Brown Blotches or Gray Coating on Leaves Means Fungal Disease
Fungi that form transparent to brown or black spots on moist ivy leaf surfaces cause leaf spots. Flecks or black dots, their spore-bearing fruiting bodies, surround some fungal spots. Often spots come together to form larger patches of dead tissue that disfigure the leaves.
A thin whitish or gray powdery coating on ivy leaves signals powdery mildew. This disease thrives in either very humid or very dry conditions on plants that are crowded. Badly infected leaves become discolored, distorted, and eventually drop off. The fungus does not kill established plants, but it mars their appearance.
Pick off and discard infected ivy leaves from plants in accessible small groundcover plantings or plants in pots. In large patches of groundcover remove dead plant debris promptly to reduce over wintering spore populations, and dig up and discard seriously infected plants along with the soil around their roots. Where practical, collect and discard all plant debris in the fall, because it harbors the fungus over the winter. Spray nearby healthy plants with a general garden fungicide containing sulfur to prevent the spread of the disease. Current research suggests that spraying healthy foliage with an anti-transpirant spray product also controls fungal infection in many plants. Follow product label instructions. For more information see the file on Controlling Fungal Disease
Swollen Bumps on Stems Caused by Canker
Canker in ivy may be caused either by fungi or bacteria. Cankers are swollen, discolored, dead areas that develop on stems from an infection that occurs in the soft tissue just under their surface. Stems commonly split open, exposing underlying tissues, and they sometimes bleed a gummy exudate. The fungi and bacteria that cause canker are easily transmitted by rain, by handling plants, or by contaminated tools. Plants weakened from injury, nutrient deficiencies, harsh winters, or pest infestations are most vulnerable to canker.
Remove and destroy infected plants or plant parts as soon as you notice them. Cut the ivy stems back several inches below the site of the cankers. Disinfect clippers and other tools in a solution of hot water laced with household bleach after using them on cankered plants. In the fall, gather and destroy all plant debris. For more information see the file on Controlling Fungal Disease
Foliage Burned by Dog Urine
Dog urine is mildly toxic to most ornamental plants, as well as lawns. Groundcover plantings of ivy bordering walks and drives often suffer from frequent visits by male dogs. Ivy foliage becomes discolored and entire stems may die.
Erect a low barrier of some attractive fencing to discourage the visits. Spray vulnerable foliage with an anti-transpirant spray to provide some ground-level protection. Also, try spraying foliage with an aerosol repellent spray. Prune out damaged areas. For more information see the file Dealing With Dogs and Cats