Beech leaf disease is a newly discovered lethal disease of beech trees believed to be caused by the nematode Litylenchus crenatae mccannii . [1] The symptoms of the disease appear as a dark green, interveinal banding pattern on the lower canopy foliage, eventually spreading throughout the tree. The symptoms appear to progress through the buds and no new leaves are produced. This eventually results in the death of the tree. The disease has the potential to drastically alter the Eastern deciduous forests of the United States on its own and through potential compounding disease effects.
The disease affects the native American beech as well as the commonly planted European beech. The estimated economic and environmental cost of the loss of the beech in Ohio alone is $225 million. The disease has no known cure. [2] [3]
The disease is caused by a type of nematode that feeds inside the leaves. The nematodes feeding cause dark bands in the leaves. The worms are most damaging to young trees, which can die in less than five years after the first signs of damage appear. In places where the disease is established, it can prove fatal to 90% of saplings. [4]
The U.S. Department of Agriculture Forest Service believes that insects, birds, as well as human movement are all possible modes of transport for the nematodes. [5]
Since its discovery in Lake County, Ohio in 2012, it has rapidly spread to 14 counties in Ohio, as well as to western Pennsylvania, Western New York, and Ontario, Canada. [6] In 2020, it was identified in eastern New York, Long Island, Connecticut, Rhode Island, and Massachusetts. [7] In 2021 it was found in Maine, [8] in Lincolnville, Waldo County, [9] and in Prince William County, Virginia. [10]
The American chestnut is a large, fast-growing deciduous tree of the beech family native to eastern North America. As is true of all species in the genus Castanea, the American chestnut produces burred fruit with edible nuts. The American chestnut was one of the most important forest trees throughout its range.
Fraxinus americana, the white ash or American ash, is a fast-growing species of ash tree native to eastern and central North America.
Beech (Fagus) is a genus of deciduous trees in the family Fagaceae, native to temperate Eurasia and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, Engleriana and Fagus. The Engleriana subgenus is found only in East Asia, distinctive for its low branches, often made up of several major trunks with yellowish bark. The better known Fagus subgenus beeches are high-branching with tall, stout trunks and smooth silver-grey bark. The European beech is the most commonly cultivated.
Quercus velutina, the black oak, is a species of oak in the red oak group, native and widespread in eastern and central North America. It is sometimes called the eastern black oak.
Fraxinus excelsior, known as the ash, or European ash or common ash to distinguish it from other types of ash, is a flowering plant species in the olive family Oleaceae. It is native throughout mainland Europe east to the Caucasus and Alborz mountains, and Great Britain and Ireland, the latter determining its western boundary. The northernmost location is in the Trondheimsfjord region of Norway. The species is widely cultivated and reportedly naturalised in New Zealand and in scattered locales in the United States and Canada.
Platanus occidentalis, also known as American sycamore, American planetree, western plane, occidental plane, buttonwood, and water beech, is a species of Platanus native to the eastern and central United States, the mountains of northeastern Mexico, extreme southern Ontario, and possibly extreme southern Quebec. It is usually called sycamore in North America, a name which can refer to other types of trees in other parts of the world. The American sycamore is a long-lived species, typically surviving at least 200 years and likely as long as 500–600 years.
Fagus grandifolia, the American beech or North American beech, is the only species of beech native to North America. Its current range comprises the eastern United States, isolated pockets of Mexico and southeastern Canada. Prior to the glacial maximum of the Pleistocene epoch, the tree flourished over most of North America, reaching California.
Juglans cinerea, commonly known as butternut or white walnut, is a species of walnut native to the eastern United States and southeast Canada.
Aesculus hippocastanum, the horse chestnut, is a species of flowering plant in the maple, soapberry and lychee family Sapindaceae. It is a large, deciduous, synoecious (hermaphroditic-flowered) tree. It is also called horse-chestnut, European horsechestnut, buckeye, and conker tree. It is not to be confused with the Spanish chestnut, Castanea sativa, which is a tree in another family, Fagaceae.
The winter moth is a moth of the family Geometridae. It is an abundant species in Europe and the Near East and a famous study organism for evaluating insect population dynamics. It is one of very few lepidopterans of temperate regions in which adults are active in late autumn and early winter. The adults use endothermy for movement in these cold temperatures. The females of this species are virtually wingless and cannot fly, but the males are fully winged and fly strongly. After the initial frosts of late fall, the females emerge from their pupae, walk to and up trees and emit pheromones in the evening to attract males. After fertilization, they ascend to lay, on average, around 100 eggs each. Typically, the larger the female moth is, the more eggs she lays.
A leaf spot is a limited, discoloured, diseased area of a leaf that is caused by fungal, bacterial or viral plant diseases, or by injuries from nematodes, insects, environmental factors, toxicity or herbicides. These discoloured spots or lesions often have a centre of necrosis. Symptoms can overlap across causal agents, however differing signs and symptoms of certain pathogens can lead to the diagnosis of the type of leaf spot disease. Prolonged wet and humid conditions promote leaf spot disease and most pathogens are spread by wind, splashing rain or irrigation that carry the disease to other leaves.
The brown-tail moth is a moth of the family Erebidae. It is native to Europe, neighboring countries in Asia, and the north coast of Africa. Descriptions of outbreaks, i.e., large population increases of several years duration, have been reported as far back as the 1500s. The life cycle of the moth is atypical, in that it spends approximately nine months as larvae (caterpillars), leaving about one month each for pupae, imagos and eggs. Larvae (caterpillars) are covered in hairs. Two red spots on the back, toward the tail, distinguish these species from other similarly hairy moth larvae. The winged adults have white wings and a hairy white body with a tuft of brown hair at the tip of the abdomen. Females lay one egg cluster, usually on the underside of a leaf of a host plant. The species is polyphagous, meaning that it feeds on many different species of trees, including pear, apple, maple and oak.
Verticillium is a genus of fungi in the division Ascomycota, and are an anamorphic form of the family Plectosphaerellaceae. The genus used to include diverse groups comprising saprobes and parasites of higher plants, insects, nematodes, mollusc eggs, and other fungi, thus the genus used to have a wide-ranging group of taxa characterised by simple but ill-defined characters. The genus, currently thought to contain 51 species, may be broadly divided into three ecologically based groups - mycopathogens, entomopathogens, and plant pathogens and related saprotrophs. However, the genus has undergone recent revision into which most entomopathogenic and mycopathogenic isolates fall into a new group called Lecanicillium.
Conopholis americana, the American cancer-root, bumeh or bear corn, is a perennial, non-photosynthesizing parasitic plant. It is from the family Orobanchaceae and more recently from the genus Conopholis but also listed as Orobanche, native but not endemic to North America. When blooming, it resembles a pine cone or cob of corn growing from the roots of mostly oak and beech trees.
Phytophthora kernoviae is a plant pathogen that mainly infects European beech and Rhododendron ponticum. It was first identified in 2003 in Cornwall, UK when scientists were surveying for the presence of Phytophthora ramorum. This made it the third new Phytophthora species to be found in the UK in a decade. It was named Phytophthora kernoviae after the ancient name for Cornwall, Kernow. It causes large stem lesions on beech and necrosis of stems and leaves of Rhododendron ponticum. It is self-fertile. It has also been isolated from Quercus robur and Liriodendron tulipifera. The original paper describing the species, stated it can infect Magnolia and Camellia species, Pieris formosa, Gevuina avellana, Michelia doltsopa and Quercus ilex. Since then many other plants have been identified as natural hosts of the pathogen. Molecular analysis has revealed that an infection on Pinus radiata, recorded in New Zealand in 1950, was caused by P. kernoviae. The pathogen was also noted on Drimys winteri, Gevuina avellana, Ilex aquifolium, Quercus ilex, Vaccinium myrtillus, Hedera helix, Podocarpus salignas.
Acleris semipurpurana is a species in the moth family Tortricidae, and one of several species of moth commonly known as oak leaftier or oak leaf tier. The larvae feed on the leaves of oak trees in the Eastern United States and southeastern Canada which can be a major cause of defoliation. The loss of leaves can kill or damage the affected trees, which are chiefly in the Lobatae or red oak section of Quercus, or oaks.
A wilt disease is any number of diseases that affect the vascular system of plants. Attacks by fungi, bacteria, and nematodes can cause rapid killing of plants, large tree branches or even entire trees.
Histomoniasis is a commercially significant disease of poultry, particularly of chickens and turkeys, due to parasitic infection of a protozoan, Histomonas meleagridis. The protozoan is transmitted to the bird by the nematode parasite Heterakis gallinarum. H. meleagridis resides within the eggs of H. gallinarum, so birds ingest the parasites along with contaminated soil or food. Earthworms can also act as a paratenic host.
The South American palm weevil, Rhynchophorus palmarum, is a species of snout beetle. The adults are relatively large black beetles of approximately one and a half inch in length, and the larvae may grow to two inches in length.
Litylenchus crenatae mccannii is a newly recognized nematode subspecies believed to be the cause of beech leaf disease.