Thousand cankers disease can be spread by moving infected black walnut wood. Trees intended for shipment should be inspected for dieback and cankers and galleries after harvest. G. morbidia or the walnut twig beetle ("Pityophthorus juglandis") are not currently known to be moved with walnut seed . There is currently no chemical therapy or prevention available for the disease making it difficult to control the spread of the disease from the west to the eastern united states. Wood from infected trees can still be used for commercial value, but safety measures such as removing the bark, phloem, and cambium to reduce the risk of spreading the disease with shipment. Quarantines have been put in place in some states to reduce the potential movement of fungus or beetle from that region. On May 17th, 2010, the Director of the Michigan Department of Agriculture issued a quarantine from affected states to protect Michigan’s black walnut ecology and production. Contacting the appropriate entities about possible infections is important to stopping or slowing the spread of thousand cankers disease.

The foamy bark canker is a disease affecting oak trees in California caused by the fungus "Geosmithia pallida" and spread by the Western oak bark beetle ("Pseudopityopthorus pubipennis"). This disease is only seen through the symbiosis of the bark beetles and the fungal pathogen. The bark beetles target oak trees and bore holes through the peridermal tissues, making tunnels within the phloem. The fungal spores are brought into these tunnels by the beetles and begin to colonize the damaged cells inside the tunnels. Symptoms of the developing fungus include wet discoloration seeping from the beetle entry holes as the fungus begins to consume phloem and likely other tissues. If bark is removed, necrosis of the phloem can be observed surrounding the entry hole(s). As the disease progresses, a reddish sap and foamy liquid oozes from entry holes, thus giving the disease the name Foamy bark canker. Eventually after the disease has progressed, the tree dies. This disease is important because of its detrimental effects on oak trees and its ability to spread to several new Californian counties in just a couple years.

Control of Leucostoma Canker is possible through a combination of pest and crop management techniques following life cycles of the trees. The strategy is implemented following techniques aimed at reducing number of pathogenic inoculum, minimizing dead or injured tissues to prevent infection, and improving tree health to improve rapid wound healing. Chemical controls have not been very effective at controlling this disease with no fungicides registered specifically for control of "Leucostoma" spp., and demethylation-inhibiting (DMI) fungicides having almost no effect on "L. persoonii".

The genus Geosmithia (Ascomycota: Hypocreales) are generally saprophytic fungi affecting hardwoods. As of its identification in 2010, the species G. morbida is the first documented as a plant pathogen. The walnut twig beetle ("Pityophthorus juglandis") carries the mycelium and conidia of the fungus as it burrows into the tree. The beetle is currently only found in warmer climates, allowing for transmission of the fungus throughout the year. Generations of the beetle move to and from black walnut trees carrying the fungus as they create galleries, the adults typically moving horizontally, and the larvae moving vertically with the grain. As they move through the wood, the beetles deposit the fungus, which is then introduced into the phloem; cankers then develop around the galleries, quickly girdling the tree. The fungus has not been found to provide any value to the beetle. A study done by Montecchio and Faccoli in Italy in 2014 found that no fungal fruiting bodies were found around or on the cankers but in the galleries. Mycelium, and sometimes conidiophores and conidia were observed in the galleries as well. No sexual stage of the fungus has currently been found.

Cherry X disease also known as Cherry Buckskin disease is caused by a plant pathogenic phytoplasma. Phytoplasma's are obligate parasites of plants and insects. They are specialized bacteria, characterized by their lack of a cell wall, often transmitted through insects, and are responsible for large losses in crops, fruit trees, and ornamentals. The phytoplasma causing Cherry X disease has a fairly limited host range mostly of stone fruit trees. Hosts of the pathogen include sweet/sour cherries, choke cherry, peaches, nectarines, almonds, clover, and dandelion. Most commonly the pathogen is introduced into economical fruit orchards from wild choke cherry and herbaceous weed hosts. The pathogen is vectored by mountain and cherry leafhoppers. The mountain leafhopper vectors the pathogen from wild hosts to cherry orchards but does not feed on the other hosts. The cherry leafhopper which feeds on the infected cherry trees then becomes the next vector that transmits from cherry orchards to peach, nectarine, and other economic crops. Control of Cherry X disease is limited to controlling the spread, vectors, and weed hosts of the pathogen. Once the pathogen has infected a tree it is fatal and removal is necessary to stop it from becoming a reservoir for vectors.

Leaf curl is a plant disease characterized by curling of leaves, and caused by a fungus, genus "Taphrina", or virus, especially genus "Begomovirus" of the family "Geminiviridae". One of the most notable types is peach leaf curl, caused by the fungus "Taphrina deformans", which infects peach, nectarine, and almond trees. "T. deformans" is found in the United States, Europe, Asia, Africa, Australia, and New Zealand. It was first introduced in America in 1852 and has now spread all over the country.

Armillaria root rot is a fungal root rot caused by several different members of the genus "Armillaria". The symptoms are variable depending on the host infected, ranging from stunted leaves to chlorotic needles and dieback of twigs and branches. However, all infected hosts display symptoms characteristic of being infected by a white rotting fungus. The most effective ways of management focus on limiting the spread of the fungus, planting resistant species, and removing infected material. This disease poses a threat to the lumber industry as well as affecting recreational areas.

Beech bark disease is a disease that causes mortality and defects in beech trees in the eastern United States and Europe. In North America, the disease occurs after extensive bark invasion by the beech scale insect, "Cryptococcus fagisuga". Through a presently unknown mechanism, excessive feeding by this insect causes two different fungi ("Neonectria faginata" (previously "Nectria coccinea var. faginata") and "Neonectria ditissima" (previously "Nectria galligena")) to produce annual cankers on the bark of the tree. The continuous formation of lesions around the tree eventually girdles it, resulting in canopy death. In Europe, "N. coccinea" is the primary fungus causing the infection. Infection in European trees occurs in the same manner as it does in North American trees. Though the disease still appears in Europe, it is less serious today than it once was.

Plant varieties that are resistant to "Armillaria" or species are resistant to other environmental or biological stressors. If the infected area has been cleared of trees, plants that are not vulnerable to the disease should be planted for five or so years until "Armillaria" is eradicated. Stump removal is also an effective management tool but can be expensive. Another way to reduce susceptibility is to maintain plant health by regular fertilization (if needed), watering during droughts, and trying not to create wounds on the plant. Fumigation can also be used to reduce the amount of inoculum.

Laminated root rot also known as yellow ring rot is caused by the fungal pathogen "Phellinus weirii". Laminated root rot is one of the most damaging root disease amongst conifers in northwestern America and true firs, Douglas-fir, Mountain hemlock, and Western hemlock are highly susceptible to infection with "P. weirii". A few species of plants such as Western white pine and Lodgepole pine are tolerant to the pathogen while Ponderosa pine is resistant to it. Only hardwoods are known to be immune to the pathogen.

Some herbaceous hosts naturally have the Cherry X Disease. Once the spreads to the cherry hosts, with the help of the mountain leafhoppers, the cherry leafhoppers can spread the disease around to other woody hosts. Here are some approaches at management with each host type:

Leucostoma canker is a fungal disease that can kill stone fruit ("Prunus" spp.). The disease is caused by the plant pathogens "Leucostoma persoonii" and "Leucostoma cinctum" (teleomorph) and "Cytospora leucostoma" and "Cytospora cincta" (anamorphs). The disease can have a variety of signs and symptoms depending on the part of the tree infected. One of the most lethal symptoms of the disease are the Leucostoma cankers. The severity of the Leucostoma cankers is dependent on the part of the plant infected. The fungus infects through injured, dying or dead tissues of the trees. Disease management can consist of cultural management practices such as pruning, late season fertilizers or chemical management through measures such as insect control. Leucostoma canker of stone fruit can cause significant economic losses due to reduced fruit production or disease management practices. It is one of the most important diseases of stone fruit tree all over the world.

Control of the beetle vector is the most effective management technique for disease prevention. Conventional methods of tree thinning and the use of insecticides have been used to combat the western bark beetles, but are only effective before the beetles have colonized and before the fungus has invaded the tree. Other cultural techniques of sanitation and overall health of the oak trees by keeping up with watering, fertilizer or mulch needs, and pruning may help. It is very important to diagnose foamy bark canker disease correctly and promptly in order to manage the disease properly because if a tree is already infected, the removal of the tree is the most effective way to prevent the disease from spreading.

Black pod disease is caused by many different "Phytophthora spp." pathogens all expressing the same symptoms in cocoa trees ("Theobroma cacao"). This pathogen if left untreated can destroy all yields; annually the pathogen can cause a yield loss of up to 1/3 and up to 10% of total trees can be lost completely. With the value of the cocoa industry throughout the world being so large there are much research and control efforts that go into these "Phytophthora spp." pathogens.

This pathogen can be located anywhere on the cocoa trees but is most noted for the black mummified look it will give to the fruit of the cocoa tree. Staying ahead of the pathogen is the best means of control, the pathogen can be greatly reduced if leaf litter is not allowed to stay on the ground and if the pathogen gets out of hand chemical control can be used. This pathogen is mostly found in tropical areas where the cocoa trees are located and need rainfall in order to spread its spores.

Bleeding canker of horse chestnut is a common canker of horse chestnut trees ("Aesculus hippocastanum", also known as conker trees) that is known to be caused by infection with several different pathogens.

Infections by the gram-negative fluorescent bacterium "Pseudomonas syringae" pathovar "aesculi" are a new phenomenon, and have caused most of the bleeding cankers on horse chestnut that are now frequently seen in Britain.

In all cases of the disease, thorough study of the distribution and intensity should be determined to help choose a management practice that’s cost effective. For example, if the disease is widespread in a pre-commercial stand, destroying the plantation may be the most effective measure. The area can then be replanted with immune or low-susceptible species. Aerial surveying is a viable tool available for use in areas where there are severely damaged systems. Other management tools include:

- Using up to date models to help predict the spread of the disease can help with management choice

- Susceptible species should not be planted within 100 feet of a disease center

- Remove as many infected roots and stumps as possible to avoid inoculation of healthy plants

- Cut all infected trees within the disease center and all uninfected trees within 50 ft of the disease center

- Stumping is an expensive, yet effective measure in gently sloping, high-quality sites with light soils. After an excavator removes the stump, pieces of the root are torn and fragmented so invading soil organisms deter long-term inocula.

- Push-falling is an alternative to post-harvest stumping. Whole trees are pushed over with machinery to expose diseased roots for removal. Push-falling is effective in areas with slopes less than 30 percent and soil textures that are sandy to sandy loam.

- Applications of chemical fumigation (such as chloropicrin) have been unsuccessful in dealing with Laminated root rot.

There are a few controls for beech bark disease. One important management strategy is prohibiting the movement of nursery stock or other materials that may harbor the beech scale insect. Insecticides, generally not applied under forest conditions, are primarily used on high-value ornamental trees. The use of other organisms as controls is also a possibility. The ladybird beetle is a beetle that preys on the beech scale insect. A fungus that parasitizes the "Neonectria" fungus could also be employed. The problem with using these organisms to control beech bark disease is that their impact on the disease has not been evaluated extensively. In a forest setting, controlling the beech bark disease is too costly. Timely salvage cutting can reduce economic losses of beech in a forest. In stands where beech bark disease is established, silvicultural best practice is to retain large overstory trees which show visual resistance (no scale, cankers or fungus), remove heavily infested/dying trees and then treat sprouts from infested trees with herbicides. The residual, resistant parent trees are future sources of resistant seed/sprouts. Resistance to beech bark disease in a stand may be 1%-5% of trees or more, with significant regional variation. A study of 35 sites in three Canadian provinces found resistance rates ranging from 2.2%-5.7%.

Velvet Blight is a disease that affects the stems, branches, leaves, fruits or trunks of plants and trees. This disease is primarily caused by three fungal species from the genus "Septobasidium": "S. bogoriense", "S. pilosum" and "S. theae".

It is known to affect mainly tea plants ("Thea" genus).

The most studied of these species is "S. bogoriense", most notably due to the work of Ernst Albert Gäumann. "S. bogoriense" is named after the Herbarium Bogoriense (Bogor, West Java, Indonesia) which is the place where it was first identified on the bark of an unspecified tree and named by E. Nyman on June 3, 1898. This species was also listed in Otto Warburg's Monsunia in 1900.

Management of Bleeding Canker of Chestnut is not definitive and treatments are currently being investigated. Because the pathogen can be spread by contaminated tools, cultural practices are important to management. Tools should be cleaned and used with caution after being used on infected trees. Recovery of trees is possible, so management strategies are focused on keeping trees healthy so they can recover. One recommendation is to add fertilizer that contains Potassium phosphate. Soil de-compaction, providing good drainage, and mulching to minimize fluctuation of soil temperature and moisture are all ways to improve or maintain tree health and to manage the pathogen.

Chemical methods can be used to help the tree maintain health and avoid progress of the disease. Management strategies are currently being developed. A study performed in 2015 examined the infection on trees and found that 41 F1 progeny parent tree source had the most promising lines of viability for resistance.

Various methods are applied.

- The most effective method is to plant peach trees against a house wall under an overhanging roof, possibly covered by a mat during the winter, to keep winter rain from the buds before they burst (and incidentally to delay blossoming until spring frosts are over), until the temperature exceeds in the spring, deactivating the fungus.

- Commercially, spraying the leaves with fungicides is the most common control method. The toxicity of these fungicides means they are not legally available to noncommercial growers in some countries. Spraying should be done in the winter well before budding. If trees are not sprayed early enough, treatment is ineffective. Copper-based mixtures (such as Bordeaux mixture) and lime sulfurs are two fungicides commonly used.

- Peach cultivars can be planted which show some resistance to peach leaf curl, or at least regenerate rapidly, such as Peach 'Benedicte'. No similarly resistant nectarine cultivar is yet known.

If a plant appears to have signs of leaf curl in a particular year, the disease will take its course, but precautions can be taken to sustain the tree or maximize crop yield: for example, treating with nitrogen and excess water to minimize stress on the tree; applying greasebands around the trunk to protect from insect infestation; and thinning the fruit. It is unclear whether removal of infected leaves from the tree is beneficial. Removing the infected leaves and fruit after they fall to the ground is sometimes also suggested but superfluous if, in the following winter, fungicides or rain protection are applied.

Acute oak decline is a disease that infects oak trees in the UK. It mainly affects mature oak trees of over 50 years old of both Britain's native oak species: the pedunculate oak ("Quercus robur") and the sessile oak ("Quercus petraea"). The disease is characterised by the trees bleeding or oozing a dark fluid from small lesions or splits in their bark. Unlike chronic oak decline, acute oak decline can lead to the death of trees within 4 to 5 years of symptoms appearing. The number of trees affected is thought to number in the low thousands, with a higher number of infected trees being found in the Midlands. It is thought to be caused by a bacterium; it is currently not known which species is involved, but scientists are actively trying to discover what is responsible. At least three genera of bacteria are possibly responsible.

In some instances, the disease is accompanied by insects attacking the trees, too, particularly the oak splendour beetle, ("Agrilus biguttatus"). These are not thought to be the cause of the disease, but rather they are opportunistically taking advantage of already weakened trees; such infestations further weaken and can hasten the death of trees.

This disease is mainly found in tropical climates in Southern Asia, however some scattering exists:

Dutch elm disease (DED) is caused by a member of the sac fungi (Ascomycota) affecting elm trees, and is spread by elm bark beetles. Although believed to be originally native to Asia, the disease was accidentally introduced into America and Europe, where it has devastated native populations of elms that did not have resistance to the disease. It has also reached New Zealand. The name "Dutch elm disease" refers to its identification in 1921 and later in the Netherlands by Dutch phytopathologists Bea Schwarz and Christine Buisman who both worked with Professor Johanna Westerdijk. The disease affects species in the genera "Ulmus" and "Zelkova", therefore it is not specific to the Dutch elm hybrid.

The causative agents of DED are ascomycete microfungi. Three species are now recognized:

- "Ophiostoma ulmi", which afflicted Europe from 1910, reaching North America on imported timber in 1928.

- "Ophiostoma himal-ulmi", a species endemic to the western Himalaya.

- "Ophiostoma novo-ulmi", an extremely virulent species from Japan which was first described in Europe and North America in the 1940s and has devastated elms in both continents since the late 1960s.

DED is spread in North America by three species of bark beetles (Family: Curculionidae, Subfamily: Scolytinae):

- The native elm bark beetle, "Hylurgopinus rufipes".

- The European elm bark beetle, "Scolytus multistriatus".

- The banded elm bark beetle, "Scolytus schevyrewi".

In Europe, while "S. multistriatus" still acts as a vector for infection, it is much less effective than the large elm bark beetle, "S. scolytus". "H. rufipes" can be a vector for the disease, but is inefficient compared to the other vectors. "S. schevyrewi" was found in 2003 in Colorado and Utah.

Other reported DED vectors include "Scolytus sulcifrons", "S. pygmaeus", "S. laevis", "Pteleobius vittatus" and "Р. kraatzi". Other elm bark beetle species are also likely vectors.

Verticillium wilt is a wilt disease of over 350 species of eudicot plants caused by six species of Verticillium genus, "V. dahliae", "V. albo-atrum", "V. longisporum", V. nubilum, V. theobromae and

V. tricorpus. (See, for example, Barbara, D.J. & Clewes, E. (2003). "Plant pathogenic Verticillium species: how many of them are there?" Molecular Plant Pathology 4(4).297-305. Blackwell Publishing.) Many economically important plants are susceptible including cotton, tomatoes, potatoes, oilseed rape, eggplants, peppers and ornamentals, as well as others in natural vegetation communities. Many eudicot species and cultivars are resistant to the disease and all monocots, gymnosperms and ferns are immune.

Symptoms are superficially similar to "Fusarium" wilts. There is no chemical control for the disease but crop rotation, the use of resistant varieties and deep plowing may be useful in reducing the spread and impact of the disease.