Leucostoma canker

Last updated
Leucostoma canker
Leukostoma Canker.jpg
Leukostoma canker on Prunus sp.
Causal agents Leucostoma persoonii , Valsaria insitiva

Leucostoma canker is a fungal disease that can kill stone fruit (Prunus spp.). [1] The disease is caused by the plant pathogens Leucostoma persoonii [2] and Leucostoma cinctum [3] (teleomorph) and Cytospora leucostoma and Cytospora cincta [4] (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.

Contents

Hosts and symptoms

The hosts for Leucostoma canker include stone fruits such as cultivated peach, plum, prune, cherry (Prunus spp.), or other wild Prunus spp. It can also be found on apple (Malus domestica). Stone fruits are referred to as drupe, which are fruits containing a seed encased by a hard endocarp, surrounded by a fleshy outer portion.

Leucostoma canker symptoms differ depending on where on the tree infection takes place. [5] Discoloration occurs in sunken patches on infected twigs. Light and dark concentric circles of narcotic tissue characterize this symptom, occurring near buds killed by cold or on leaf scars. Infections on the nodes are seen 2–4 weeks after bud break. [6] As time passes, darkening occurs within diseased tissues, and eventually, amber gum ooze may seep from infected tissue. [7] Nodal infections are particularly vulnerable in one-year-old shoots that develop within the center of the tree. If fungal growth persists without treatment, scaffold limbs and large branches will likely become invaded within a short time frame. Cankers occurring on branches that are the product of such infections will contain dead twigs or twig stubs at the canker's center.

The most striking symptom of infection includes cankers located on the main trunk, branch crotches, scaffold limbs, and older branches. [3] A symptom called “flagging” can be found on necrotic scaffold limbs. The cankers are parallel to the long axis of the stem and take on an oval shape. Normally, large-scale production of amber colored gum marks the first external symptom of such cankers. While gum production is the typical plant response to irritation, the gum secretion of Leucostoma occurs in bulk amounts. This gum darkens as time passes, gradually leading to the drying and cracking of bark; thus exposing the blackened tissue below.

As the tree continues to mature in the early growing season, the tree resists additional fungal penetration through the formation of callus rings surrounding the canker. However, the Leucostoma generally reinvades the tissue late in the growing season while the tree switches into dormancy. Due to the alteration of callus production and canker formation, cankers with circular callus rings are usually observed.

Foliar symptoms might develop from branch or twig infections. Symptoms include chlorosis, wilting, and necrosis. Signs include small black structures on dead bark which contain pycnidia. [7]

Disease cycle

Leucostoma Canker of Stone Fruits Disease Cycle Stone Fruit Disease Cycle.jpg
Leucostoma Canker of Stone Fruits Disease Cycle

Although the Leucostoma pathogen can undergo sexual stages, the asexual cycle is far more important for disease development.

The fungus that causes disease overwinters in cankers or previously invaded dead wood. Environmental cues, such as cool, moist weather in the early spring, cause conidia to be released from pycnidia in sticky masses. The conidia are then spread via wind or water splashes. Conidia then germinate and the fungi begins to colonize provided that the environment is wet. The fungus is incapable of invading healthy bark and must enter the tree through injured, dying, or dead tissues. [3] Leucostoma commonly enters through weak, winter-killed twigs in the center of the tree. Moreover, it gains entry through winter-injured wood on limbs and trunks. It also can enter through short, dead pruning stubs, leaf scars, winter-killed buds on small twigs, and on poorly healed pruning cuts.

Upon invasion, fungal growth moves into healthy adjacent tissue. This fungal growth is slow, but the expansion continues even at temperatures just above freezing. As the temperature rises above 50 degrees Fahrenheit, the tree actively starts to grow and a callus is usually formed around the canker. The defense mechanism, however, is outmatched in the fall and following spring when the dormant tree is unable to defend itself. The repeated tree growth eventually forms a new callus, and an annual pattern of callus formation and canker expansion leads to the development of concentric callus rings around the first infection site.

Pycnidia develop throughout the growing season within the colonized tissues. Conidia are then produced inside the pycnidia and can be released when conditions are favorable: i.e. humid weather. As a result, vulnerable tissues are at risk of initial invasion throughout most parts of the year, although it most commonly occurs in autumn and spring following winter injury and leaf scars.

Environment

Leucostoma canker can be found in the Northeastern United States, from the cooler regions surrounding Lake Ontario to the warmer areas in the lower Hudson Valley. It can also be found the Southeastern United States on peaches. In California and Idaho, it has been found on plum and prune trees. In Europe, the disease can be found on apricot, peach, and cherry. Leucostoma canker has also been witnessed in South America and Japan. [1]

The spread of disease is favored in cool, wet, and humid conditions in late fall or early spring when conidia are most abundant. Regions with irrigation are particularly vulnerable to disease, for conidia thrive whenever water is available. Studies have shown that there are positive correlations between the number of disease causing agents (conidia), and the number of hours that temperatures are between 10 and 15 degrees Celsius. These data also correlate to the duration of moisture and amount of time humidity conditions are above 90 percent. These conditions are all optimal for disease. Without humidity and wet conditions, disease does not occur.

Management

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. [1]

Cultural management

There are many strategies to cultural management. Establishment of new trees that are disease free by trying to plant trees as soon as they are received from the nursery to reduce the amount of stress the tree undergoes to reduce the amount of dead tissue. Apply insecticides to prevent insects such as, peach tree borer to prevent disease causing conidia from entering wounded parts of the tree that the insects create. Prune trees appropriately and at the correct time when buds start to break to promote wide angled branching. Infection at pruning sites is less common when done during late spring because of the smaller amount of inoculum present at this time. Inspect trees occasionally and removed any dead branches to prevent infection at these sites. Training trees properly also helps foster decreased amount of disease. Training trees during the first season to have branches develop wide crotch angles to sustain long orchard life. Avoid excessive and late fertilization during cold season to avoid low temperature injury. Fertilize trees during the early spring to prevent cold-susceptible growth. [1]

Genetic resistance

Selecting cultivars is important and the best ones are the cultivars resistant to cold temperatures. As plant pathologists have learned better ways to develop more efficient resistance to the Leucostoma canker pathogens, there have been many really effective cultivars developed that can be used. However, the cultivars that offer the best resistance to cold temperatures have a higher ability to resist infection due to injury or wounding. A peach cultivar resistant to cold temperatures would be Redhaven one that is especially, recommended for Missouri and some nectarine cultivars include RedGold, Crimson Snow, Crimson Gold, Sunglo and many more. [8]

Importance

Cankers Peach Cytospora Canker 012.jpg
Cankers

Leucostoma canker [9] is one of the most important diseases on stone fruit. Leucostoma persoonii [10] is most significant on peaches, nectarines, and cherries in regions with cold winters. The first records of peach tree cankers caused by this pathogen were documented in western New York in 1900. The disease was then sighted in southern Ontario twelve years later. [1] Leucostoma canker decreases the bearing surface of fruiting trees and shortens the tree’s lifespan. Additionally, it considerably raises the costs of disease management.

As limbs with cankers die or break off due to the stress of holding fruit, economic losses add. Parts of the branch distal to the canker often become less fruitful, and eventually the canker will enlarge to reach the branch, effectively killing it. Trees with numerous cankers show strikingly reduced yield. Since peach trees are trimmed to hold 3 to 4 main scaffold limbs, the death of even one of the main limbs causes a 25 to 50% loss of fruit production. [1]

Related Research Articles

<i>Uncinula necator</i> Species of fungus

Uncinula necator is a fungus that causes powdery mildew of grape. It is a common pathogen of Vitis species, including the wine grape, Vitis vinifera. The fungus is believed to have originated in North America. European varieties of Vitis vinifera are more or less susceptible to this fungus. Uncinula necator infects all green tissue on the grapevine, including leaves and young berries. It can cause crop loss and poor wine quality if untreated. The sexual stage of this pathogen requires free moisture to release ascospores from its cleistothecia in the spring. However, free moisture is not needed for secondary spread via conidia; high atmospheric humidity is sufficient. Its anamorph is called Oidium tuckeri.

<span class="mw-page-title-main">Black rot (grape disease)</span> Species of fungus

Grape black rot is a fungal disease caused by an ascomycetous fungus, Guignardia bidwellii, that attacks grape vines during hot and humid weather. “Grape black rot originated in eastern North America, but now occurs in portions of Europe, South America, and Asia. It can cause complete crop loss in warm, humid climates, but is virtually unknown in regions with arid summers.” The name comes from the black fringe that borders growing brown patches on the leaves. The disease also attacks other parts of the plant, “all green parts of the vine: the shoots, leaf and fruit stems, tendrils, and fruit. The most damaging effect is to the fruit”.

<span class="mw-page-title-main">Diplodia tip blight</span> Fungal disease of conifers

Diplodia tip blight, also known as Sphaeropsis blight, is a widespread disease affecting conifers caused by an opportunistic fungal pathogen, Diplodia sapinea. It is found in “both hemispheres between the latitudes 30° and 50° north and south". The diseases symptoms include: damping off and collar rot of seedlings, stem canker, root disease, and, most commonly, shoot blight. These symptoms have caused significant economic loss to nurseries and pine plantations. In a nursery in the north-central United States, losses of 35% have been reported. Shoot blight and eventual die back can cause a reduction of marketable volume in timber by 63%. Infection of terminal shoots can result in dead-top which significantly limits the usable length of the tree trunk. The presence of the pathogen in concert with severe weather conditions can lead to extreme loss. Following a severe hailstorm in South Africa, nearly 5,000 acres of pine plantation were infected with Diplodia tip blight. It was necessary to prematurely harvest large swaths of the plantations resulting in a loss of 45%. Areas that were not harvested prematurely still suffered an average timber loss of 11%.

<span class="mw-page-title-main">Phomopsis cane and leaf spot</span> Fungal plant disease

Phomopsis cane and leaf spot occurs wherever grapes are grown. Phomopsis cane and leaf spot is more severe in grape-growing regions characterized by a humid temperate climate through the growing season. Crop losses up to 30% have been reported to be caused by Phomopsis cane and leaf spot.

<i>Monilinia fructicola</i> Species of fungus

Monilinia fructicola is a species of fungus in the order Helotiales. A plant pathogen, it is the causal agent of brown rot of stone fruits.

<i>Botryosphaeria dothidea</i> Species of fungus

Botryosphaeria dothidea is a plant pathogen that causes the formation of cankers on a wide variety of tree and shrub species. It has been reported on several hundred plant hosts and on all continents except Antarctica. B. dothidea was redefined in 2004, and some reports of its host range from prior to that time likely include species that have since been placed in another genus. Even so, B. dothidea has since been identified on a number of woody plants—including grape, mango, olive, eucalyptus, maple, and oak, among others—and is still expected to have a broad geographical distribution. While it is best known as a pathogen, the species has also been identified as an endophyte, existing in association with plant tissues on which disease symptoms were not observed. It can colonize some fruits, in addition to woody tissues.

<i>Botryosphaeria obtusa</i> Species of fungus

Botryosphaeria obtusa is a plant pathogen that causes frogeye leaf spot, black rot and cankers on many plant species. On the leaf it is referred to as frogeye leaf spot; this phase typically affects tree and shrubs. In fruit such as the apple, cranberry and quince, it is referred to as black rot, and in twigs and trunks it causes cankers.

Leptosphaeria coniothyrium is a plant pathogen. It can be found around the world.

<i>Nectria cinnabarina</i> Fungal plant pathogen

Nectria cinnabarina, also known as coral spot, is a plant pathogen that causes cankers on broadleaf trees. This disease is polycyclic and infects trees in the cool temperate regions of the Northern Hemisphere. N. cinnabarina is typically saprophytic, but will act as a weak parasite if presented with an opportunity via wounds in the tree or other stressors that weaken the tree's defense to the disease. A study published in 2011 showed that this complex consists of at least 4 distinct species. There are only a few ways to manage this disease with techniques such as sanitation and pruning away branches that have the cankers. N. cinnabarina is not as significant a problem as other Nectria spp., some of which are the most important pathogens to infect hardwood trees.

<i>Lasiodiplodia theobromae</i> Species of fungus

Lasiodiplodia theobromae is a plant pathogen with a very wide host range. It causes rotting and dieback in most species it infects. It is a common post harvest fungus disease of citrus known as stem-end rot. It is a cause of bot canker of grapevine. It also infects Biancaea sappan, a species of flowering tree also known as Sappanwood.

<i>Botryosphaeria ribis</i> Species of fungus

Botryosphaeria ribis is a fungal plant pathogen that infects many trees causing cankers, dieback and death.

<i>Diaporthe helianthi</i> Species of fungus

Diaporthe helianthi is a fungal pathogen that causes Phomopsis stem canker of sunflowers. In sunflowers, Phomopsis helianthi is the causative agent behind stem canker. Its primary symptom is the production of large canker lesions on the stems of sunflower plants. These lesions can eventually lead to lodging and plant death. This disease has been shown to be particularly devastating in southern and eastern regions of Europe, although it can also be found in the United States and Australia. While cultural control practices are the primary method of controlling for Stem Canker, there have been a few resistant cultivars developed in regions of Europe where the disease is most severe.

The plant pathogenic fungus Leucostoma kunzei is the causal agent of Leucostoma canker, a disease of spruce trees found in the Northern Hemisphere, predominantly on Norway spruce and Colorado blue spruce. This disease is one of the most common and detrimental stem diseases of Picea species in the northeastern United States, yet it also affects other coniferous species. Rarely does it kill its host tree; however, the disease does disfigure by killing host branches and causing resin exudation from perennial lesions on branches or trunks.

Eutypella canker is a plant disease caused by the fungal pathogen Eutypella parasitica. This disease is capable of infecting many species of maple trees and produces a large, distinguishable canker on the main trunk of the tree. Infection and spread of the disease is accomplished with the release of ascospores from perithecia. Therefore, the best way to manage the Eutypella canker is to remove trees that have been infected. If infected, it can decrease the quality of wood cut for lumber and can thus have a negative economic impact.

<i>Dibotryon morbosum</i> Species of fungus

Dibotryon morbosum or Apiosporina morbosa is a plant pathogen, which is the causal agent of black knot. It affects members of the Prunus genus such as; cherry, plum, apricot, and chokecherry trees in North America. The disease produces rough, black growths that encircle and kill the infested parts, and provide habitat for insects.

Mal secco is a disease caused by the conidia-producing fungal plant pathogen Phoma tracheiphila. It mainly causes disease to citrus trees in the Mediterranean. In particular it causes damage to lemon trees in the Mediterranean basin. The plant pathogen, Phoma tracheiphila, is rain- and wind-disseminated.

<span class="mw-page-title-main">Phomopsis blight of juniper</span> Species of fungus

Phomopsisblight of juniper is a foliar disease discovered in 1917 caused by the fungal pathogen Phomopsis juniperovora. The fungus infects new growth of juniper trees or shrubs, i.e. the seedlings or young shoots of mature trees. Infection begins with the germination of asexual conidia, borne from pycnidia, on susceptible tissue, the mycelia gradually move inwards down the branch, and into the main stem. Management strategies mainly include removing and destroying diseased tissue and limiting the presence of moisture on plants. Junipers become resistant to infection as they mature and the young yellow shoots turn dark green. Preventive strategies include planting only resistant varieties and spraying new growth with fungicide until plants have matured.

<span class="mw-page-title-main">Peach scab</span> Fungal disease of stone fruits

Peach scab, also known as peach freckles, is a disease of stone fruits caused by the fungi Cladosporium carpophilum. The disease is most prevalent in wet and warm areas especially southern part of the U.S. as the fungi require rain and wind for dispersal. The fungus causes scabbing, lesions, and defoliating on twig, fruit, and leaf resulting in downgrade of peach quality or loss of fruits due to rotting in severe cases.

<span class="mw-page-title-main">Hypoxylon canker of shade trees</span> Tree disease

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.

<span class="mw-page-title-main">Shot hole disease</span> Fungal disease of plants

Shot hole disease is a serious fungal disease that creates BB-sized holes in leaves, rough areas on fruit, and concentric lesions on branches. The pathogen that causes shot hole disease is Wilsonomyces carpophilus.

References

  1. 1 2 3 4 5 6 "Leucostoma canker of stone fruits". Apsnet.org.
  2. ↑ Jensen, Carolyn J. P.; Adams, Gerard C. (1 January 1995). "Nitrogen Metabolism of Leucostoma persoonii and L. cincta in Virulent and Hypovirulent Isolates". Mycologia. 87 (6): 864–875. doi:10.2307/3760862. JSTOR   3760862.
  3. 1 2 3 Biggs, Alan R. "Leucostoma Canker of Stone Fruits". Caf.wvu.edu. Archived from the original on 2013-10-20. Retrieved 2013-10-20.
  4. ↑ Wensley, R. N. (1 March 1971). "The microflora of peach bark and its possible relation to perennial canker (Leucostoma cincta (Fr.) v. Hohnel (Valsa cincta))". Can. J. Microbiol. 17 (3): 333–337. doi:10.1139/m71-056. PMID   5551316.
  5. ↑ "Leucostoma facts" (PDF). Fruit.cornell.edu. Retrieved 22 March 2022.
  6. ↑ "Search". Nysipm.cornell.edu.
  7. 1 2 "Fungal Cankers of Trees -- Sustainable Urban Landscapes". Store.extension.iastate.edu. Retrieved 22 March 2022.
  8. ↑ "MG6 Fruit Production - University of Missouri Extension". Extension.missouri.edu.
  9. ↑ Puterka, G. J.; Scorza, R.; Brown, M. W. (1 November 1993). "Reduced Incidence of Lesser Peachtree Borer and Leucostoma Canker in Peach-Almond Hybrids". J. Am. Soc. Hort. Sci. 118 (6): 864–867. doi: 10.21273/JASHS.118.6.864 .
  10. ↑ Adams, Gerard C.; Surve-Iyer, Rupa S.; Iezzoni, Amy F. (1 January 2002). "Ribosomal DNA Sequence Divergence and Group I Introns within the Leucostoma Species L. cinctum, L. persoonii, and L. parapersoonii sp. nov., Ascomycetes That Cause Cytospora Canker of Fruit Trees". Mycologia. 94 (6): 947–967. doi:10.2307/3761863. JSTOR   3761863. PMID   21156569.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.