Ambrosia Beetles These pests are attracted by compromised trees, including trees that are weakened, dead or dying, or have been recently cut. Once attracted to your property, they can spread to and attack freshly cut lumber and lumber in decks before it is dried, causing pinhole defects and dark staining in the outer wood.
Japanese Beetles Summer, while a time of blooming flowers, lush trees, and green lawns, is also the time when Japanese beetles get to work. These pests feed on more than 300 species of ornamental shrubs and trees. Their destruction causes leaves to turn brown and ultimately die and fall off.
Aphids Aphids thrive in spring and fall and can become a major infestation very quickly. Although they will attack any part of a tree or shrub, younger growth is especially vulnerable. These pests do their damage by sucking out fluids from leaves and stems, which weakens the plant, and by spreading viruses, which could kill some plants. To spot aphids, look for small black, white, green, or pink oval-shaped pests; they can range in size from 1/16 to 1/4 inches.
Whitefliies Whiteflies thrive in warm, sunny conditions and reproduce quickly. You’ll find them on buds, stems, and the undersides of leaves, where, like aphids, they damage the tree or shrub by sucking out its fluids. A tell-tale sign of whiteflies is what gardeners call “plant dandruff”: a cloud of tiny white specks that emerge into the air when you rustle the leaves of a plant.
Lace Bugs These pests are a threat to many ornamental trees and shrubs. They attack a broad range of evergreen and deciduous trees and shrubs and often go undetected until the infested plants show severe damage.
Pine Borer Beetles Trees and shrubs that produce cones are most susceptible to this pest. The larvae tunnel beneath the bark into the conductive tissue of the plant, interfering with sap flow and harming the cambium, a layer of tissue important for the growth of the plant. They can cause enough damage to severely stunt or even kill affected plants, often without much warning. Many pine borers also carry fungi that further pose risks to the health of cone-bearing trees and shrubs.
Powdery Mildew This fungal disease appears as a gray coating with the consistency of talcum powder. It tends to attack shrubs and crepe myrtles in late spring and early summer, but you might also find it on the leaves, flowers, and even fruit of some other perennials and garden vegetables.
Scale Insects These look like tiny brown or orange blobs and can often be found near the veins on the undersides of leaves, as well as on leaf stems or in leaf joints. They produce a sticky substance as they feed, which gets onto the foliage and attracts dark sooty mold. Plants that exhibit yellowing or slow or distorted growth may have a scale insect problem.
Leaf Spot Leaf spot is a descriptive term encompassing a number of diseases that affect the foliage of ornamentals and shade trees. The majority of leaf spots are caused by funguses but some are caused by bacteria. Some insects also cause damage that can be confused with a leaf spot disease due to fungi or bacteria. Leaf spots on trees are very common and generally do not require spraying. The disease may result in some defoliation, but an established plant can tolerate almost complete defoliation when it happens late in the season or when it does not occur every year. Small or newly planted trees that become defoliated are more at risk of suffering damage until they become established.