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Plant NameTypeDescription 
Leaf scorch (marginal leaf necrosis)Linden(Tilia)DiseaseBrowning and dieback of leaf margins and tips can be a symptom of several problems that restrict water flow to the leaves. Drought, excess heat, excess sunlight, overfertilization, and herbicide injury are all possible causes. Damage to the root system or trunk may also show as wilting and leaf necrosis due to the inhibition of water uptake and movement. Salt damage may occur on plants growing near sidewalks due to winter use of de-icing products. Some lindens including Tilia americana (American linden or American basswood) are reported to be intolerant of air pollution and may develop marginal leaf necrosis or other leaf damage if exposed to high levels of pollution.
Leaf gallsLinden(Tilia)InsectLeaves of linden or basswood trees (Tilia sp.) may be infested by eriophyid mites. These tiny, worm-like or spindle-shaped mites feed on leaf tissues and cause galls to develop. Damage may appear on the upper or lower surface of leaves. Elongated, pimple-like galls (often called nail galls, nipple galls, or fingergalls) are most commonly seen on the upper leaf surface. They are slender, with a round or pointed tip. Generally about 1/5 to 1/2 inch long, these galls may be greenish-yellow, pinkish, red, or brown in color. These nail galls typically appear around June and mature by July-August. Some lindens develop felt-like masses of tiny hairs on the back of the leaf instead of the protruding nail galls. Known as erineum, this damage is also caused by eriophyid mites. The erineum may be yellow to brown in color, and the damaged areas may appear on the upper leaf surface as discolored patches. Eriophyid mites on linden do not cause serious injury to trees; the damage is mainly aesthetic.
Linden aphidLinden(Tilia)InsectBasswood or linden (Tilia spp.) trees planted along streets and in parking lots are commonly infested with linden aphids. The linden aphid feeds in colonies on the underside of leaves. Wingless aphids are green with black stripes or dots across the abdomen. Winged adults are similar in appearance, with black markings on the wings. Feeding damage from the linden aphid is usually minor, but can cause some leaf or shoot distortion if populations are very high. These aphids produce large amounts of honeydew, a sweet, sticky material. It can attract honeydew-feeding ants, which protect aphid colonies from predators. Honeydew may also promote an unsightly growth of black false sooty mold. Honeydew and false sooty mold can be a nuisance, particularly in street or parking lot plantings, but does not harm the tree.