Boston Ivy Sticky Leaf Diseases

Honeydew

• Both indoor and outdoor plants may eventually attract insects that produce honeydew. These insects feed by sucking the sap from the plants, but cannot always fully metabolize the sap they find. When this happens, they extrude the partially digested plant juices in the form of honeydew. Honeydew is sticky and tends to drip indiscriminately. If honeydew is left on the plant in question, sooty mildew colonies may form, further complicating the plant's situation.

Aphids

• Aphids are small, soft-bodied insects that are found hiding on the undersides of plant leaves. These insects are often farmed by ants, who protect them in exchange for honeydew. Even if you don't see aphids, it's reasonable to assume your plant has an infestation if ants are problematic. Treat houseplants for aphids by washing them often in soapy water (invert them in the soapy water if possible). Outdoor ivies should be sprayed with a garden hose if the infestation is small -- this will preserve the predatory insects that hunt aphids. Major infestations can be treated with environmentally friendlier insecticidal soaps, pyrethrins or rotenone.

Scale

• Scale insects may be difficult to detect, since their adult forms often look like small bumps or growths on the host plant. Fortunately, the scale that commonly infests Boston ivy is somewhat distinctive. Check the undersides of leaves for cottony growths or white waxy substances. They may be located on stems as well, where they drip honeydew onto leaves below. Control scale by hand-picking whenever possible. These insects can also be smothered with dormant oil applied in the winter or insecticidal soaps. Imidacloprid can be useful if it's applied during the Boston ivy's active growing period.

Whitefly

• Whitefly is a less common pest of Boston ivy, but another that exudes honeydew. It's found throughout the Gulf states and California, but is less common in cooler climates. Whiteflies resemble tiny moths with two sets of wings that expand no more than 1/8 inch. Like other leaf-feeders, they're generally found on the undersides of leaves. Whiteflies will often take flight when plants are disturbed. They can be treated chemically with bifenthrin, permethrin, resmethrin, pyrethrins and neem oil.

Precautions

• Insect control can be difficult on large ivies, but resist the temptation to throw a lot of chemicals at Boston ivy. It's very sensitive to pesticides such as carbaryl. This chemical will cause leaf drop or severe foliage injury to the Boston ivy. Always read pesticide labels carefully before applying them to any plant.