The pathogenic fungus Cryphonectria parasitica is a member of the Ascomycota. This necrotrophic fungus is native to East Asia and South East Asia and was introduced into Europe and North America in the early 1900s. Strains of the fungus spread more or less rapidly and caused significant tree loss in both regions. Strains of the fungus can be more or less virulent.
Pinus elliottii, commonly known as slash pine, is a conifer tree native to the Southeastern United States. Slash pine is named after the "slashes" – swampy ground overgrown with trees and bushes – that constitute its habitat. Other common names include swamp pine, yellow slash pine, and southern Florida pine. Slash pine has two different varieties: P. e. var. elliottii and P. e. var. densa. Historically, slash pine has been an important economic timber for naval stores, turpentine, and resin. The wood of slash pine is known for its unusually high strength, especially for a pine. It exceeds many hardwoods and is even comparable to very dense woods such as black ironwood.
Arbutus menziesii, or Pacific madrone, is a species of broadleaf evergreen tree in the family Ericaceae. It has waxy foliage, a contorted growth habit, and flaky bark.
Larix laricina, commonly known as the tamarack, hackmatack, eastern larch, black larch, red larch, or American larch, is a species of larch native to Canada, from eastern Yukon and Inuvik, Northwest Territories east to Newfoundland, and also south into the upper northeastern United States from Minnesota to Cranesville Swamp, West Virginia; there is also an isolated population in central Alaska.
Juglans nigra, the eastern American black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to central and eastern North America, growing mostly in riparian zones.
Juglans cinerea, commonly known as butternut or white walnut, is a species of walnut native to the eastern United States and southeast Canada.
A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticulture. Their causes include a wide range of organisms as fungi, bacteria, mycoplasmas and viruses. The majority of canker-causing organisms are bound to a unique host species or genus, but a few will attack other plants. Weather and animal damage can also cause stress to the plant resulting in cankers. Other causes of cankers is pruning when the bark is wet or using un-sterilized tools.
Citrus canker is a disease affecting Citrus species caused by the bacterium Xanthomonas. Infection causes lesions on the leaves, stems, and fruit of citrus trees, including lime, oranges, and grapefruit. While not harmful to humans, canker significantly affects the vitality of citrus trees, causing leaves and fruit to drop prematurely; a fruit infected with canker is safe to eat, but too unsightly to be sold. Citrus canker is mainly a leaf-spotting and rind-blemishing disease, but when conditions are highly favorable, it can cause defoliation, shoot dieback, and fruit drop.
Carya glabra, the pignut hickory, is a common, but not abundant species of hickory in the oak-hickory forest association in the Eastern United States and Canada. Other common names are pignut, sweet pignut, coast pignut hickory, smoothbark hickory, swamp hickory, and broom hickory. The pear-shaped nut ripens in September and October, has a sweet maple like smell, and is an important part of the diet of many wild animals. The wood is used for a variety of products, including fuel for home heating. Its leaves turn yellow in the Fall.
Physalospora abdita is a fungal plant pathogen that causes cankers on, among other species, mangoes, persimmons, maples, alders, and oaks. It is a saprobe specifically on oaks and causes twig blights of persimmon.
Populus grandidentata, commonly called large-tooth aspen, big-tooth aspen, American aspen, Canadian poplar, or white poplar, is a deciduous tree native to eastern North America.
The National Elm Trial was an American volunteer effort to evaluate a range of newly developed elm cultivars as replacements for elms destroyed by Dutch elm disease. The Colorado State University College of Agricultural Sciences coordinated the trial.
Thousand cankers disease (TCD) is a recently recognized disease of certain walnuts. The disease results from the combined activity of the walnut twig beetle and a canker producing fungus, Geosmithia morbida. Until July 2010 the disease was only known to the western United States where over the past decade it has been involved in several large scale die-offs of walnut, particularly black walnut, Juglans nigra. However, in late July 2010 a well-established outbreak of the disease was found in the Knoxville, Tennessee, area. This new finding is the first locating it within the native range of its susceptible host, black walnut. In 2013, an outbreak was found in the Veneto region of Italy, where the disease has been found on both black walnut and English walnut.
George Henry Hepting was an American forest scientist and plant pathologist. Hepting was Chief Plant Pathologist at Southeastern Forest Experiment Station of US Forest Service and a member of the National Academy of Sciences. He has been called a "pioneer leader in forest pathology".
Entoleuca mammata is a species of fungus in the genus Entoleuca. It is responsible for the plant disease hypoxylon canker in hardwood trees such as quaking aspen and other aspens and poplars, Salix myrsinifolia and other willow species, rowan, Sitka alder, birch, apple, oak, and hop-hornbeam.
Septoria musiva, correct taxonomic name: Sphaerulina musiva, is an ascomycete fungus responsible of a leaf spot and canker disease on poplar trees. It is native on the eastern cottonwood poplar Populus deltoides, causing only a leaf spot symptom. On susceptible hybrid poplars, S. musiva causes necrotic lesions on the leaves which lead to premature defoliation, and cankers on the stem and branches which can reduce growth, predispose the tree to colonisation by secondary organisms, and cause stem breakage.
Pityophthorus juglandis, also known as the walnut twig beetle, is a weevil that feeds on several different species of walnut trees (Juglans). It is one of only a few species in the genus Pityophthorus that is associated with hardwoods and the only one associated with walnut trees.
Hypoxylon canker of shade trees is a weak ascomycete fungus that negatively affects growth and can eventually lead to the death of weak or diseased host trees. There are many different species that affect different trees. For example, Hypoxylon atropunctatum, a common species, is found on oak trees, Hypoxylon tinctor affects sycamore trees, and Hypoxylon mammatum infests aspen trees.
Species which are not native to a forest ecosystem can act as an agent of disturbance, changing forest dynamics as they invade and spread. Invasive insects and pathogens (diseases) are introduced to the United States through international trade, and spread through means of natural and human-dispersal. Invasive insects and pathogens are a serious threat to many forests in the United States and have decimated populations of several tree species, including American chestnut, American elm, eastern hemlock, whitebark pine, and the native ash species. The loss of these tree species is typically rapid with both short and long-term impacts to the forest ecosystem.
Pascal "Pat" Pompey Pirone was a botanist, plant pathologist, urban horticulturalist, science communicator, and author.
