Gummosis is the formation of patches of a gummy substance on the surface of certain plants, particularly fruit trees. [1] This occurs when sap oozes from wounds or cankers as a reaction to outside stimuli such as adverse weather conditions, infections, insect problems, or mechanical damage. It is understood as a plant physiological disease. [2]
Liquefaction of wood pieces, especially young wood, causes disease foci to form under the bark, which secrete a gummy colorless to amber liquid, a plant gum, which then oozes out between the bark pieces on branches and trunk. The gum is composed of various sugar compounds and acids.
The main causes are physiological disturbances of the tree, which can affect the water balance, among other things. Frost, injuries, but also bacteria and fungi, especially of the genus Hallimasch (Armillaria), can contribute to gum flow.
Prunus is a genus of trees and shrubs in the flowering plant family Rosaceae that includes plums, cherries, peaches, nectarines, apricots, and almonds. The genus has a cosmopolitan distribution, being native to the North American temperate regions, the neotropics of South America, and temperate and tropical regions of Eurasia and Africa, There are about 340 accepted species as of March 2024. Many members of the genus are widely cultivated for their fruit and for decorative purposes. Prunus fruit are drupes, or stone fruits. The fleshy mesocarp surrounding the endocarp is edible while the endocarp itself forms a hard, inedible shell called the pyrena. This shell encloses the seed, which is edible in some species, but poisonous in many others. Besides being eaten off the hand, most Prunus fruit are also commonly used in processing, such as jam production, canning, drying, and the seeds for roasting.
Specific replant disease is a malady that manifests itself when susceptible plants such as apples, pears, plums, cherries and roses are placed into soil previously occupied by a related species. The exact causes are not known, but in the first year the new plants will grow poorly. Root systems are weak and may become blackened, and plants may fail to establish properly.
Juglans nigra, the eastern American black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to North America. It grows mostly in riparian zones, from southern Ontario, west to southeast South Dakota, south to Georgia, northern Florida and southwest to central Texas. Wild trees in the upper Ottawa Valley may be an isolated native population or may have derived from planted trees.
A bark beetle is the common name for the subfamily of beetles Scolytinae. Previously, this was considered a distinct family (Scolytidae), but is now understood to be a specialized clade of the "true weevil" family (Curculionidae). Although the term "bark beetle" refers to the fact that many species feed in the inner bark (phloem) layer of trees, the subfamily also has many species with other lifestyles, including some that bore into wood, feed in fruit and seeds, or tunnel into herbaceous plants. Well-known species are members of the type genus Scolytus, namely the European elm bark beetle S. multistriatus and the large elm bark beetle S. scolytus, which like the American elm bark beetle Hylurgopinus rufipes, transmit Dutch elm disease fungi (Ophiostoma). The mountain pine beetle Dendroctonus ponderosae, southern pine beetle Dendroctonus frontalis, and their near relatives are major pests of conifer forests in North America. A similarly aggressive species in Europe is the spruce ips Ips typographus. A tiny bark beetle, the coffee berry borer, Hypothenemus hampei is a major pest on coffee plantations around the world.
Betula lenta is a species of birch native to eastern North America, from southern Maine west to southernmost Ontario, and south in the Appalachian Mountains to northern Georgia.
Prunus serotina, commonly called black cherry, wild black cherry, rum cherry, or mountain black cherry, is a deciduous tree or shrub in the rose family Rosaceae. Despite being called black cherry, it is not very closely related to the commonly cultivated cherries, such as sweet cherry, sour cherry and Japanese flowering cherries, which belong to Prunus subg. Cerasus. Instead, P. serotina belongs to Prunus subg. Padus, a subgenus also including Eurasian bird cherry and chokecherry. The species is widespread and common in North America and South America.
Girdling, also called ring-barking, is the circumferential removal or injury of the bark of a branch or trunk of a woody plant. Girdling prevents the tree from sending nutrients from its foliage to its roots, resulting in the death of the tree over time, and can also prevent flow of nutrients in the other direction depending on how much of the xylem is removed. A branch completely girdled will fail and when the main trunk of a tree is girdled, the entire tree will die, if it cannot regrow from above to bridge the wound. Human practices of girdling include forestry, horticulture, and vandalism. Foresters use the practice of girdling to thin forests. Extensive cankers caused by certain fungi, bacteria or viruses can girdle a trunk or limb. Animals such as rodents will girdle trees by feeding on outer bark, often during winter under snow. Girdling can also be caused by herbivorous mammals feeding on plant bark and by birds and insects, both of which can effectively girdle a tree by boring rows of adjacent holes.
Aegle marmelos, commonly known as bael, also Bengal quince, golden apple, Japanese bitter orange, stone apple or wood apple, is a species of tree native to the Indian subcontinent and Southeast Asia. It is present in India, Pakistan, Bangladesh, Sri Lanka, and Nepal as a naturalized species. The tree is considered to be sacred by Hindus and Buddhists.
Acer is a genus of trees and shrubs commonly known as maples. The genus is placed in the soapberry family, Sapindaceae, along with lychee and horse chestnut. There are approximately 132 species, most of which are native to Asia, with a number also appearing in Europe, northern Africa, and North America. Only one species, Acer laurinum, extends to the Southern Hemisphere. The type species of the genus is the sycamore maple, Acer pseudoplatanus, the most common maple species in Europe. Maples usually have easily recognizable palmate leaves and distinctive winged fruits. The closest relatives of the maples are the horse chestnuts. Maple syrup is made from the sap of some maple species. It is one of the most common genera of trees in Asia. Many maple species are grown in gardens where they are valued for their autumn colour.
Hymenaea courbaril, the courbaril or West Indian locust, is a tree common in the Caribbean, Central America, and South America. It is a hardwood that is used for furniture, flooring, and decoration. Its hard fruit pods have edible dry pulp surrounding the seeds. Its sap, called animé, is used for incense, perfume, and varnish.
Prunus cerasoides, commonly known as the wild Himalayan cherry,sour cherry or pahhiya is a species of deciduous cherry tree in the family Rosaceae.
Slime flux, also known as bacterial slime or bacterial wetwood, is a bacterial disease of certain trees, primarily elm, cottonwood, poplar, boxelder, ash, aspen, fruitless mulberry and oak. A wound to the bark, caused by pruning, insects, poor branch angles or natural cracks and splits, causes sap to ooze from the wound. Bacteria may infect this sap causing it to darken and stain the bark, eventually taking on a foamy appearance and unpleasant odor. This slimy ooze becomes toxic to the bark and eats into the tree. Additionally, the fermented sap attracts insects like flies, ants, and maggots.
Armillaria tabescens is a species of fungus in the family Physalacriaceae. It is a plant pathogen. The mycelium of the fungus is bioluminescent.
Phytophthora citrophthora, also known as brown rot of citrus, is a soil borne oomycete that infects several economically important citrus crops. A diagnostic symptom of P. citrophthora is gummosis, wherein lesions around the base of the tree exude sap. Other common symptoms include dark longitudinal lesions forming at the soil line, a sour smell, and eventual cracking of the bark. Advanced symptoms include yellowing and necrosis of the tree canopy. Girdling action caused by the pathogen around the trunk can often cause the collapse of the tree. Resistant lemon varieties have been developed and their implementation has been effective at controlling the spread of the disease. Fruits that have been infected with P. citrophthora exhibit symptoms of brown rot characterized by a distinct odor. This disease is most active in the moderate temperatures of spring, fall, and winter months, opposite of most other Phytophthora species.
Erythricium salmonicolor is a species of fungus in the family Corticiaceae. Basidiocarps are effused, corticioid, smooth, and pinkish and grow on wood. The fungus is a commercially significant plant pathogen which has become a serious problem, especially in Brazil. Erythricium salmonicolor causes Pink Disease, most commonly in Citrus, although E. salmonicolor has a wide host range including rubber and cacao trees. Pink Disease causes branch and stem die-back due to canker formation. The cankers are recognizable by gum exudation and longitudinal splitting of the bark.
Commiphora myrrha, called myrrh, African myrrh, herabol myrrh, Somali myrrhor, common myrrh, is a tree in the Burseraceae family. It is one of the primary trees used in the production of myrrh, a resin made from dried tree sap. The tree is native to the Arabian Peninsula and to Africa. It is called 'mur' (المر) in Arabic, meaning bitter. It famously comes from Mecca, so it is called 'Mur Makki'.
The citrus gummy bark viroid is a strain of Hop stunt viroid, and thus is a member of the genus Hostuviroid.
Leucostoma canker is a fungal disease that can kill stone fruit. 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 trees all over the world.
Gummy stem blight is a cucurbit-rot disease caused by the fungal plant pathogen Didymella bryoniae. Gummy stem blight can affect a host at any stage of growth in its development and affects all parts of the host including leaves, stems and fruits. Symptoms generally consist of circular dark tan lesions that blight the leaf, water soaked leaves, stem cankers, and gummy brown ooze that exudes from cankers, giving it the name gummy stem blight. Gummy stem blight reduces yields of edible cucurbits by devastating the vines and leaves and rotting the fruits. There are various methods to control gummy stem blight, including use of treated seed, crop rotation, using preventative fungicides, eradication of diseased material, and deep plowing previous debris.
Gum is a sap or other resinous material associated with certain species of the plant kingdom. This material is often polysaccharide-based and is most frequently associated with woody plants, particularly under the bark or as a seed coating. The polysaccharide material is typically of high molecular weight and most often highly hydrophilic or hydrocolloidal.