The bodies of spruce bud scale resemble a bud and are difficult to see. Look for black sooty mold on the bark as one confirmation of the scale's presence. Peak...
Black pineleaf scale is an armored scale that mostly occurs on trees stressed by drought, nutrient deficiency, or other cause. Crawler activity begins June 30...
Often the cause of dieback in birch is bronze birch borer.
Sycamore antracnose symptoms on foliage.
Sycamore anthracnose causes tiny cankers around buds or on twigs.
Powdery mildew on rose.
Powdery mildew on Norway maple.
Powdery mildew on honeysuckle.
Maple anthracnose infections start out as pale olive in color, and tend to follow the leaf veins.
Elm leafminer adult, laying her eggs inside the leaf tissue.
Elm leafminer larva seen inside a mine.
European elm flea weevil adults chew holes in leaves.
European elm sawfly larvae feed communally, and when disturbed, lift their back sides as a defensive measure.
A single caterpillar causes a large mass of pitch.
Pitch mass borers feed on pine resin, and do not bore into the tree. But bad infestations do cause the tree to spend energy producing the large amounts of sap...