Tree Pests

Tent Caterpillars (hardwoods)

The _________ and _________ are first seen in the spring in eastern U.S. deciduous forests. The _________ makes its nest in the fork of branches. The _________ actually builds no tent but is by far the most destructive of the two. The favorite food of _________ is wild cherry but oaks, maples and many other shade and forest trees are attacked. The _________ can strip extensive stands of trees of all leaves. The attacked tree's growth is effected.

AMERICAN CHESTNUT BLIGHT

The _________ has virtually eliminated the American chestnut as a commercial species from eastern hardwood forests. You only now see the chestnut as a sprout as the fungus eventually kills every tree within the natural range. There is no effective control for _________ even after decades of massive research. The loss of American Chestnut to the __________ is one of forestry's saddest stories.

Tussock Moth (conifers)

The Douglas-fir _________ is an important defoliator of true firs and Douglas-fir in Western North America. The larvae feeds on current year's foliage, causing it to shrivel, turn brown and will kill or top-kill the tree. The pest is considered serious and can kill up to one-third of trees in a stand of Douglas-fir and deform significant numbers of trees remaining alive.

Emerald Ash Borer (hardwoods)

The _________ is an exotic, wood-boring beetle discovered in Michigan in 2002. _________ is blamed for killing millions of ash trees annually and forcing regional quarantines on exporting firewood and tree nursery stock in several states. This _________ r could potentially decimate arboricultural ash plantings and natural ash stands in the eastern United States. The _________ larvae feed on the cambial bark. These S-shaped feeding galleries will kill limbs and can ultimately girdle the tree. Infested ash trees exhibited a top-down crown dieback, dense sprouting from trunks (epicormic shoots), and other signs of tree stress including the yellowing of foliage called the "ash yellows".

Wooly Adelgids (conifers)

The balsam and hemlock _________ are threatening entire tree species in parts of the eastern U.S. forest. Although not a commercial timber threat (with the exception of Christmas tree growers) the _________ attacks balsam fir and the eastern hemlocks killing entire stands on critical sites. The sap-sucking insect feeds where the needle attaches to the twig. Researchers believe the aphid's toxic saliva is the agent that does the damage

ARMILLARIA ROOT DISEASE

The disease attacks hardwoods and softwoods and kills shrubs, vines, and forbs in every state. It is pervasive in North America, commercially destructive, a major cause of oak decline and is my pick for the worst disease. The _________ can kill trees that are already weakened by competition, other pests, or climatic factors. The fungi also infect healthy trees, either killing them outright or predisposing them to attacks by other fungi or insects.

Gypsy Moth (hardwoods)

The exotic _________ is one of the "most notorious pests of hardwood trees in the Eastern United States." Since 1980, the _________ larvae has defoliated close to a million or more forested acres each year. The _________ was introduced into the United States in 1862. The insect lays visible buff-colored egg masses as leaves emerge in the spring. These masses hatch into hungry larvae that quickly defoliate hardwoods. Several defoliations can frequently kill trees under stress.

Elm Bark Beetle (hardwoods)

The native _________ is critical for overland spread of Dutch elm disease (DED) and is worthy of being included in this "worst" list. The beetle does not critically harm a tree by its boring but by transporting a deadly tree disease. The DED fungus is transmitted to healthy trees in two ways: 1) this _________ transmits spores from diseased to healthy trees and 2) root grafting can also spread the disease when elms are tightly spaced. None of the native North American elms are immune to DED but the American elm is especially susceptible.

Asian Longhorn Beetles/ Borers (hardwoods)

This group of insects includes the exotic _________. The _________ was first found in Brooklyn, New York in 1996 but has now been reported in 14 states and threatening more. The adult insects lays eggs in an opening in the bark. The larvae then bore large galleries deep into the wood. These "feeding" galleries disrupt the vascular functioning of the tree and eventually weaken the tree to the point that the tree literally falls apart and dies.

Bark Beetles (conifers)

_________ are the most devastating insects to attack pines. They exist throughout North America in both eastern and western forms, are commercially destructive and my pick for the worst insect. The Dendroctonus/Ips sp. will kill healthy trees and trees already weakened by other factors. The _________ girdle trees while building egg-laying galleries. The lack of sap flow immediately kills the tree, the insects move to adjacent live trees and the damage spreads.

Spruce Budworm (conifers)

_________ is one of the most destructive native insects in the northern spruce and fir forests of the Eastern United States and Canada. Outbreaks occur every few years and balsam fir is the species most severely damaged by the _________. These outbreaks have resulted in the loss of millions of cords of spruce and fir. The newly hatched larva feeds on needles or expanding buds. Severe damage to these structures causes the tree to defoliate and die.

Pales and White Pine Weevils (conifers)

_________ is the most destructive insect of newly planted pine seedlings in the Eastern United States. Adult _________ are attracted to cutover pine lands where they breed in stumps and old root systems. Seedlings planted in freshly cut areas are injured or killed by adult ________ that feed on the stem bark. The _________ is the "most serious and economically important native insect pest of spruce and pine regeneration in Canada" says Canadian Forest Service.

ANTHRACNOSE DISEASES

_________ of hardwood trees are widespread throughout the Eastern United States. The most common symptom of this group of diseases is dead areas or blotches on the leaves. The diseases are particularly severe on American sycamore, the white oak group, black walnut, and dogwood. The greatest impact of _________ is in the urban environment. Reduction of property values result from the decline or death of shade trees.

DUTCH ELM DISEASE

_________ primarily affects American and European species of elm. _________ is a major disease problem throughout the range of elm in the United States. The economic loss resulting from death of high value urban trees is considered by many to be "devastating. "Fungus infection results in clogging of vascular tissues, preventing water movement to the crown and causing visual symptoms as the tree wilts and dies. American elm is highly susceptible.

OAK WILT (Ceratocystis fagacearum)

_________, _________ _________, is a disease that affects oaks (especially red oaks, white oaks, and live oaks). It is one of the most serious tree diseases in the eastern United States, killing thousands of oaks each year in forests and landscapes. The fungus takes advantage of wounded trees - the wounds promote infection. The fungus can move from tree to tree through roots or by insects. Once the tree is infected there is no known cure.