Sycamore and Planes. Singly or in clusters, leaves brown, curl, and die. Angular blotches appear on other leaves, and dark patches on their stems, which break. The whole tree may become naked, but will grow a new suit later. This is anthracnose, a disease caused by a fungus that overwinters in fallen leaves and in cankers on twigs or branches. Control: A mercuric or copper fungicidal spray when buds are swelling, and twice again ten days apart if the weather is damp. Rake up dead leaves, prune infected members.

Birch, Elm, Holly, Lilac. Lacy patterns appear in the leaves, where their green cells are chewed out by leaf miners. On the thick holly and lilac leaves these patterns will look like opaque blotches. Split the leaf membranes apart and you can see the tiny worms through a hand lens. Control: Anticipate the adults early in May with a stomach poison; hit the second generation in July with chlordane, lindane, or dieldrin.

Pines, colonies of inch-long green or yellow worms with black or brown heads appear, chewing off needles at a great rate. When you poke at them they rear up indignantly and stiffen to simulate needles. These are sawfly larvae. Control: Any strong stomach-contact poison.

Ash, the blossoms wither and become dark clusters which stay on all winter. These are flower galls, caused by a mite. Control: Spray with malathion and a good sticker in the spring when buds are swelling.

Dogwood. New leaves are small and pale, turning red prematurely. Twigs and whole branches die. Examination of the inner bark and sapwood low on the tree will show discolorations. This is crown canker, caused by a fungus called Phytophthora cactorum which attacks through lesions in the trunk and roots. Control: Trace the lesions well back, excavate them thoroughly, and apply shellac; feed the trees to help them resist further invasion, and spray early with a fungicide.