![Crassula ovata gall](https://upload.wikimedia.org/wikipedia/commons/7/72/Crassula_ovata_gall.jpg)
Galls (from the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
, 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external
tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...
tissues, similar to
benign tumor
A benign tumor is a mass of cells (tumor) that does not invade neighboring tissue or metastasize (spread throughout the body). Compared to malignant (cancerous) tumors, benign tumors generally have a slower growth rate. Benign tumors have re ...
s or
wart
Warts are typically small, rough, hard growths that are similar in color to the rest of the skin. They typically do not result in other symptoms, except when on the bottom of the feet, where they may be painful. While they usually occur on the ...
s in animals. They can be caused by various
parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
s, from
virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's 1 ...
es,
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
and
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
, to other
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...
s,
insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s and
mite
Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evid ...
s. Plant galls are often highly organized structures so that the cause of the gall can often be determined without the actual agent being identified. This applies particularly to some insect and mite plant galls. The study of plant galls is known as cecidology.
In human
pathology
Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in ...
, a gall is a raised sore on the skin, usually caused by chafing or rubbing.
Causes of plant galls
Insects and mites
![Oak marble gall sectioned](https://upload.wikimedia.org/wikipedia/commons/d/df/Oak_marble_gall_sectioned.JPG)
Insect galls are the highly distinctive plant structures formed by some
herbivorous
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
insects as their own microhabitats. They are plant tissue which is controlled by the insect. Galls act as both the habitat and food source for the maker of the gall. The interior of a gall can contain edible nutritious starch and other tissues. Some galls act as "physiologic sinks", concentrating resources in the gall from the surrounding plant parts. Galls may also provide the insect with physical protection from predators.
Insect galls are usually induced by chemicals injected by the
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
e of the insects into the plants, and possibly mechanical damage. After the galls are formed, the larvae develop inside until fully grown, when they leave. In order to form galls, the insects must take advantage of the time when plant cell division occurs quickly: the growing season, usually spring in temperate climates, but which is extended in the tropics.
The
meristem
The meristem is a type of tissue found in plants. It consists of undifferentiated cells (meristematic cells) capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants. These cells conti ...
s, where plant cell division occurs, are the usual sites of galls, though insect galls can be found on other parts of the plant, such as the leaves,
stalks,
branch
A branch, sometimes called a ramus in botany, is a woody structural member connected to the central trunk (botany), trunk of a tree (or sometimes a shrub). Large branches are known as boughs and small branches are known as twigs. The term '' ...
es,
bud
In botany, a bud is an undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of a stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be spec ...
s,
root
In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the sur ...
s, and even
flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...
s and
fruit
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
s. Gall-inducing insects are usually species-specific and sometimes tissue-specific on the plants they gall.
Indicator insects
Gall-inducing insect
A gall-inducing insect is any insect that can cause the growth of galls within plants. There are several groups of insects that meet this description. They include the gall wasps, scales, gall midges, aphids, psyllids and certain species of lea ...
s include
gall wasp
Gall wasps, also incorrectly called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this generall ...
s,
gall midge
Cecidomyiidae is a family of flies known as gall midges or gall gnats. As the name implies, the larvae of most gall midges feed within plant tissue, creating abnormal plant growths called galls. Cecidomyiidae are very fragile small insects us ...
s,
gall flies (e.g., the
goldenrod gall fly
The goldenrod gall fly (''Eurosta solidaginis''), also known as the goldenrod ball gallmaker, is a species of fly native to North America. The species is best known for the characteristic galls it forms on several species in the ''Solidago'', or ...
),
Agromyzidae
The Agromyzidae are a family commonly referred to as the leaf-miner flies, for the feeding habits of their larvae, most of which are leaf miners on various plants.
A worldwide family of roughly 2,500 species, they are small, some with wing leng ...
,
aphid
Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A t ...
s (such as ''
Melaphis chinensis
''Schlechtendalia chinensis'', the Chinese sumac aphid, is an aphid species, and the only species in the genus ''Schlechtendalia''.
The species produce galls on the Chinese sumac (''Rhus chinensis''). The gall is called ''Chinese gall'', ''Gall ...
'', ''
Pemphigus spyrothecae'', and ''
Pemphigus betae
''Pemphigus betae'', also known as the sugarbeet root aphid, is a species of gall-forming aphid that forms galls specifically on the commonly found narrowleaf cottonwood (aka the willow-leaved poplar tree), '' Populus angustifolia''.
Sugarbeet ...
''),
scale insects
Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than the ...
,
psyllid
Psyllidae, the jumping plant lice or psyllids, are a family of small plant-feeding insects that tend to be very host-specific, i.e. each plant-louse species only feeds on one plant species (monophagous) or feeds on a few closely related plants ( ...
s,
thrips
Thrips ( order Thysanoptera) are minute (mostly long or less), slender insects with fringed wings and unique asymmetrical mouthparts. Different thrips species feed mostly on plants by puncturing and sucking up the contents, although a few are ...
, gall moths (e.g., ''
Epiblema scudderiana''), and
weevils
Weevils are beetles belonging to the superfamily Curculionoidea, known for their elongated snouts. They are usually small, less than in length, and herbivorous. Approximately 97,000 species of weevils are known. They belong to several families, ...
.
Galls produced by insects and mites include:
*
Ash
Ash or ashes are the solid remnants of fires. Specifically, ''ash'' refers to all non-aqueous, non- gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash ...
flower gall: this gall is caused by a small mite that causes irregular distortion of male flowers. The galls are initially green, then dry and turn brown.
* Ash midrib gall: normally long, these galls are succulent and have thick walls. A small cavity within each gall contains one or more small maggots, the larval stages of very small flies called midges. Female midges lay their eggs in very young leaflets during early spring. Gall formation begins soon after the eggs are laid. Specifics of the biology of this insect are not known. The galls probably do not harm tree health.
*
Elm
Elms are deciduous and semi-deciduous trees comprising the flowering plant genus ''Ulmus'' in the plant family Ulmaceae. They are distributed over most of the Northern Hemisphere, inhabiting the temperate and tropical-montane regions of North ...
cockscomb gall: these distinct galls, caused by an aphid, are about long and about high. The irregular edge of the gall and its red color at maturity account for the common name. The galls dry, harden and turn brown as they age. Aphids may be seen through a slit-like opening in the underside of the gall. This insect has a complex life cycle—it forms galls on elm in early summer, then feeds on grass roots later in the summer. The galls apparently do not cause significant harm to the tree.
*
Hackberry leaf gall: this gall is caused by a small ( long) aphid-like insect with sucking mouthparts called a jumping plant louse. The adults spend the winter under bark crevices and can invade houses in large numbers in the fall. Females lay eggs over a long period of time beginning when leaves begin to unfold from the buds in the spring. Feeding by the nymphs that hatch from these eggs causes abnormal plant growth that forms a pouch. The psyllids remain inside the galIs until they emerge as adults in late summer to early fall. There is one generation each year. Heavy infestations can result in premature leaf drop which over a series of years may affect tree health.
*
Honeylocust
The honey locust (''Gleditsia triacanthos''), also known as the thorny locust or thorny honeylocust, is a deciduous tree in the family Fabaceae, native to central North America where it is mostly found in the moist soil of river valleys. Honey ...
pod gall: this gall is caused by a small fly (midge). The sunburst cultivar appears to be very susceptible to this pest. Infested leaves have globular or pod-like distortions that contain one to several small maggots ( long). Infestations begin when females lay eggs in young leaflets. There are five or more generations each year. Infested leaves often drop prematurely and repeated damage can kill small branches. New shoots develop at the base of dead twigs. As a result, the natural shape of the tree may be lost.
* Oak gall: see
Oak apple
Oak apple or oak gall is the common name for a large, round, vaguely apple-like gall commonly found on many species of oak. Oak apples range in size from in diameter and are caused by chemicals injected by the larva of certain kinds of gall ...
* Petiole and stipule galls: thick globe-like galls can develop on leaf petioles and stems. Many of these are caused by insects called
phylloxerans which are very similar to aphids. The hard, woody galls may remain on the tree for several years. Usually, there is one generation each year and the insects over winter on the tree in the egg stage.
*
Willow
Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...
shoot galls: these swellings on shoots, twigs, or leaf petioles, may be caused by small flies (midges) or small wasps (sawflies). The gall increases in size as long as the immature stages are active. They cause no significant injury. The infestation may be reduced by pruning and destroying the galled areas before the adult insect emerges, usually in late summer.
*
Witchhazel gall: this gall is caused by an aphid that passes the winter in eggs laid on twigs of the plant. Feeding by the aphid causes the formation of conical galls on the upper side of the leaf. Each gall, produced by a single aphid, later becomes filled with offspring. Mature aphids with wings leave the galls in late spring and early summer and fly to
birch
A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 ...
. After several generations there, the insects return to witch hazel to lay the eggs that survive the winter. No galls are formed on the birch.
*
Banksia
''Banksia'' is a genus of around 170 species in the plant family Proteaceae. These Australian wildflowers and popular garden plants are easily recognised by their characteristic flower spikes, and fruiting "cones" and heads. ''Banksias'' range i ...
infructescence galls: microscopic Eriophyid mites (
Eriophyidae
Eriophyidae is a family of more than 200 genera of mites, which live as plant parasites, commonly causing galls or other damage to the plant tissues and hence known as gall mites. About 3,600 species have been described, but this is probably l ...
) commonly cause swellings on young infructescences of ''
Banksia integrifolia
''Banksia integrifolia'', commonly known as the coast banksia, is a species of tree that grows along the east coast of Australia. One of the most widely distributed ''Banksia'' species, it occurs between Victoria and Central Queensland in a b ...
'' and ''
Banksia marginata
''Banksia marginata'', commonly known as the silver banksia, is a species of tree or woody shrub in the plant genus ''Banksia'' found throughout much of southeastern Australia. It ranges from the Eyre Peninsula in South Australia to north of Arm ...
'' in south-eastern Australia
Fungi
![RHODODENDRON FERRUGINEUM - GENTO - IB-137 (Neret)](https://upload.wikimedia.org/wikipedia/commons/2/24/RHODODENDRON_FERRUGINEUM_-_GENTO_-_IB-137_%28Neret%29.JPG)
Many
rust fungi
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales (previously known as Uredinales).
An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus ''Puccinia'', are currently a ...
induce gall formation, including
western gall rust
Pine-pine gall rust, also known as western gall rust, is a fungal disease of pine trees. It is caused by ''Endocronartium harknessii'' (asexual name is ''Peridermium harknessii''), an autoecious, endocyclic, Rust (fungus), rust fungus that grows i ...
, which infects a variety of
pine
A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...
trees and
cedar-apple rust
''Gymnosporangium juniperi-virginianae'' is a plant pathogen that causes cedar-apple rust. In virtually any location where apples or crabapples (''Malus'') and Eastern red cedar (''Juniperus virginiana'') coexist, cedar apple rust can be a destr ...
. Galls are often seen in ''
Millettia pinnata
''Millettia pinnata'' is a species of tree in the pea family, Fabaceae, native to eastern and tropical Asia, Australia, and Pacific islands. It is often known by the synonym ''Pongamia pinnata''. Its common names include Indian beech and Pongame ...
'' leaves and fruits. Leaf galls appear like tiny clubs; however, flower galls are globose. ''
Exobasidium
''Exobasidium'' is a genus of fungi in the family Exobasidiaceae. The genus has a widespread distribution, especially in northern temperate regions, and contains about 50 species. Many of the species in this genus are plant pathogen
Plan ...
'' often induces spectacular galls on its hosts.
The fungus ''
Ustilago esculenta
''Ustilago esculenta'' is a species of fungus in the Ustilaginaceae, a family of smut fungi. It is in the same genus as the fungi that cause corn smut, loose smut of barley, false loose smut, covered smut of barley, loose smut of oats, and o ...
'' associated with ''Zizania latifolia'', a wild rice, produces an edible gall highly valued as a food source in the
Zhejiang
Zhejiang ( or , ; , also romanized as Chekiang) is an eastern, coastal province of the People's Republic of China. Its capital and largest city is Hangzhou, and other notable cities include Ningbo and Wenzhou. Zhejiang is bordered by Jiang ...
and
Jiangsu
Jiangsu (; ; pinyin: Jiāngsū, Postal romanization, alternatively romanized as Kiangsu or Chiangsu) is an Eastern China, eastern coastal Provinces of the People's Republic of China, province of the China, People's Republic of China. It is o ...
provinces of China.
Bacteria and viruses
''
Agrobacterium tumefaciens
''Agrobacterium radiobacter'' (more commonly known as ''Agrobacterium tumefaciens'') is the causal agent of crown gall disease (the formation of tumours) in over 140 species of eudicots. It is a rod-shaped, Gram-negative soil bacterium. Sympto ...
'' and ''
Pseudomonas savastanoi
''Pseudomonas savastanoi'' is a gram-negative plant pathogenic bacterium that infects a variety of plants. It was once considered a pathovar of ''Pseudomonas syringae,'' but following DNA-relatedness studies, it was instated as a new species.
It ...
'' are examples of gall-causing bacteria.
Gall forming virus was found on rice plants in central Thailand in 1979 and named rice gall dwarf. Symptoms consisted of gall formation along leaf blades and sheaths, dark green discoloration, twisted leaf tips and reduced numbers of tillers. Some plants died in the glasshouse in later stages of infection. The causal agent was transmitted by ''
Nephotettix nigropictus
''Nephotettix nigropictus'' is a species of true bug in the family Cicadellidae. It is a pest of millet
Millets () are a highly varied group of small-seeded grasses, widely grown around the world as cereal crops or grains for fodder and ...
'' after an incubation of two weeks. Polyhedral particles of 65 nm diameter in the cytoplasm of phloem cells were always associated with the disease. No serologic relationship was found between this virus and that of rice dwarf.
Nematodes
Nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...
s are microscopic worms that live in the soil. Some nematodes (''Meloidogyne'' species or
root-knot nematodes
Root-knot nematodes are plant-parasitic nematodes from the genus ''Meloidogyne''. They exist in soil in areas with hot climates or short winters. About 2000 plants worldwide are susceptible to infection by root-knot nematodes and they cause appro ...
) cause galls on the roots of susceptible plants. The galls are small, individual and beadlike in some hosts. In other plant species galls may be massive accumulations of fleshy tissue more than in diameter. Some ectoparasitic nematodes (nematodes that live outside the plant in the soil), such as sting and stubby-root nematodes, may cause root tips to swell. Nitrogen-fixing bacteria (''
Rhizobium
''Rhizobium'' is a genus of Gram-negative soil bacteria that fix nitrogen. ''Rhizobium'' species form an endosymbiotic nitrogen-fixing association with roots of (primarily) legumes and other flowering plants.
The bacteria colonize plant cells ...
'' species) cause swellings on the roots of most legumes (such as clover, peas and beans). These swellings, called nodules, are easily distinguished from root-knot galls by differences in how they are attached to the root and their contents. Nodules are loosely attached to the root, while root-knot galls originate from infection at the center of the root, so they are an integral part of the root. In addition, fresh ''Rhizobium'' nodules have a milky pink-to-brown liquid inside them, while root-knot galls have firmer tissues and contain female root-knot nematodes (creamy white beads less than in diameter) inside the gall tissues.
Other plants
Mistletoe
Mistletoe is the common name for obligate hemiparasitic plants in the order Santalales. They are attached to their host tree or shrub by a structure called the haustorium, through which they extract water and nutrients from the host plant.
...
can form galls on its hosts.
Uses
Galls are rich in
resin
In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on natu ...
s and
tannic acid
Tannic acid is a specific form of tannin, a type of polyphenol. Its weak acidity ( pKa around 6) is due to the numerous phenol groups in the structure. The chemical formula for commercial tannic acid is often given as C76H52O46, which correspon ...
and have been used widely in the manufacturing of permanent
ink
Ink is a gel, sol, or solution that contains at least one colorant, such as a dye or pigment, and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, reed pen, or quill. Thi ...
s (such as
iron gall ink
Iron gall ink (also known as common ink, standard ink, oak gall ink or iron gall nut ink) is a purple-black or brown-black ink made from iron salts and tannic acids from vegetable sources. It was the standard ink formulation used in Europe for t ...
) and astringent ointments, in
dyeing
Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular ...
, and in
leather tanning
Tanning is the process of treating skins and hides of animals to produce leather. A tannery is the place where the skins are processed.
Tanning hide into leather involves a process which permanently alters the protein structure of skin, makin ...
.
The
Talmud
The Talmud (; he, , Talmūḏ) is the central text of Rabbinic Judaism and the primary source of Jewish religious law (''halakha'') and Jewish theology. Until the advent of modernity, in nearly all Jewish communities, the Talmud was the cente ...
records using
gallnut
Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...
s as part of the tanning process as well as a dye-base for ink.
Medieval
Arabic
Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...
literature records many uses for the gall, called in Arabic. The
Aleppo gall, found on
oak
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
trees in northern
Syria
Syria ( ar, سُورِيَا or سُورِيَة, translit=Sūriyā), officially the Syrian Arab Republic ( ar, الجمهورية العربية السورية, al-Jumhūrīyah al-ʻArabīyah as-Sūrīyah), is a Western Asian country loc ...
, was among the most important exports from Syria during this period, with one merchant recording a shipment of galls from
Suwaydiyya near
Antioch
Antioch on the Orontes (; grc-gre, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου, ''Antiókheia hē epì Oróntou'', Learned ; also Syrian Antioch) grc-koi, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου; or Ἀντιόχεια ἡ ἐπ ...
fetching the high price of 4½
dinar
The dinar () is the principal currency unit in several countries near the Mediterranean Sea, and its historical use is even more widespread.
The modern dinar's historical antecedents are the gold dinar and the silver dirham, the main coin of ...
s per 100 pounds. The primary use of the galls was as a
mordant
A mordant or dye fixative is a substance used to set (i.e. bind) dyes on fabrics by forming a coordination complex with the dye, which then attaches to the fabric (or tissue). It may be used for dyeing fabrics or for intensifying stains in ...
for black dyes; they were also used to make a high-quality
ink
Ink is a gel, sol, or solution that contains at least one colorant, such as a dye or pigment, and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, reed pen, or quill. Thi ...
. The gall was also used as a medication to treat
fever
Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...
and
intestinal
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans ...
ailments.
The larvae in galls are useful for a survival food and fishing bait, as in the
Indigenous Australian
Indigenous Australians or Australian First Nations are people with familial heritage from, and membership in, the ethnic groups that lived in Australia before British colonisation. They consist of two distinct groups: the Aboriginal peoples ...
foods
bush coconut
The bush coconut, or bloodwood apple, is an Australian bush tucker food. It is an insect gall with both plant and animal components: an adult female scale insect and her offspring (of genus ''Cystococcus'') live in a gall induced on a bloodwo ...
and
mulga apple
The mulga apple is an Australian bush tucker food, often eaten by the Indigenous Australians of Central Australia.
The mulga apple is in fact a combination of plant and animal; the insect gall grows inside the wood of the mulga tree ''(Acacia a ...
. Nutgalls also produce
purpurogallin
Purpurogallin is an aglycone natural product. It is an orange-red solid that is soluble in polar organic solvents but not in water. Its glycoside (ether-linked to sugar), called dryophantin, is found in nutgalls and oak barks. Purpurogallin ca ...
.
The gall of ''
Rhus chinensis
''Rhus chinensis'', the Chinese sumac or nutgall tree, is a deciduous shrub or small tree in the genus ''Rhus''. Growing to tall, it has downy shoots and leaves comprising several leaflets. These turn red in autumn before falling.
The plant is ...
'', ''Galla chinensi'', has long been considered to possess many medicinal properties.
[Zhang, J.; Li, L.; Kim, S. H.; Hagerman, A. E., Lü, J. (2009). "Anti-cancer, anti-diabetic and other pharmacologic and biological activities of penta-galloyl-glucose". ''Pharmaceutical Research'' 26(9): 2066–2080. .]
Gallery
File:Maple leaf gall.jpg, Gall on a maple
''Acer'' () is a genus of trees and shrubs commonly known as maples. The genus is placed in the family Sapindaceae.Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 nd more or less continuously updated since http ...
leaf
File:Diplolepis-rosae.jpg, Rose bedeguar gall on a wild rose in summer
File:Andricus foecundatrix Quercus01.jpg, Oak artichoke gall
Andricus foecundatrix (formerly ''Andricus fecundator'') is a parthenogenetic gall wasp which lays a single egg within a leaf bud, using its ovipositor, to produce a gall known as an oak artichoke gall, oak hop gall, larch-cone gall or hop strobi ...
(''Andricus fecundator'')
File:Gallwespe bedient sich Eichel2.jpg, Knopper gall
''Andricus quercuscalicis'' is a gall wasp species inducing knopper galls.
Knopper galls develop as a chemically induced distortion of growing acorns on pedunculate oak (''Quercus robur'' L.) trees, caused by gall wasps, which lay eggs in buds w ...
(''Andricus quercuscalicis
''Andricus quercuscalicis'' is a gall wasp species inducing knopper galls.
Knopper galls develop as a chemically induced distortion of growing acorns on pedunculate oak (''Quercus robur'' L.) trees, caused by gall wasps, which lay eggs in buds w ...
'')
File:Diplolepis Quercus02.jpg, Knopper gall (''Andricus quercuscalicis'')
File:Eikengallen op mannelijke bloeiwijze.jpg, ''Neuroterus albipes'' forma ''laeviusculus''
File:Eucalyptus gall.jpg, Eucalyptus
''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as euca ...
leaf gall
File:Oak Gall.jpg, ''Andricus kollari
''Andricus kollari'', also known as the marble gall wasp, is a parthenogenetic species of wasp which causes the formation of marble galls on oak trees. Synonyms for the species include ''Cynips kollari'', ''Andricus quercusgemmae'', ''A. minor'', ...
'' oak gall
Oak apple or oak gall is the common name for a large, round, vaguely apple-like gall commonly found on many species of oak. Oak apples range in size from in diameter and are caused by chemicals injected by the larva of certain kinds of gall ...
File:Andricus kollari - Capanne di Marcarolo.JPG, ''Andricus kollari'' oak gall
File:Gymnosporangium juniperii telial form.jpg, Gymnosporangium
''Gymnosporangium'' is a genus of heteroecious plant-pathogenic fungi which alternately infect members of the family Cupressaceae, primarily species in the genus ''Juniperus'' (junipers), and members of the family Rosaceae in the subfamily Amygd ...
File:Oak marble galls 1.JPG, Oak
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
marble galls, one with a gall fly exit hole and another with ''Phoma gallarum'' fungal attack
File:Red-Pea gall Cynips divisa on Oak.JPG, Red-pea gall
The red-pea gall or red currant gall develops as a chemically induced distortion arising from the underside of the mid-rib of a vein on ''Quercus'' species and it is attached by a short stalk or peduncle. The red-wart gall is the sexual phase of ...
(''Cynips divisa'') on pedunculate oak
''Quercus robur'', commonly known as common oak, pedunculate oak, European oak or English oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native to most of Europe west of the Caucasus. It is widel ...
File:Andricus lignicola - Cola-nut Gall.JPG, Cola-nut gall
Cola-nut gallsDarlington, Arnold (1975) ''The Pocket Encyclopaedia of Plant Galls in Colour.'' Pub. Blandford Press. Poole. . P. 155. develop as a chemically induced distortion of leaf axillary or terminal buds on pedunculate oak (''Quercus robu ...
s (''Andricus lignicola
Cola-nut gallsDarlington, Arnold (1975) ''The Pocket Encyclopaedia of Plant Galls in Colour.'' Pub. Blandford Press. Poole. . P. 155. develop as a chemically induced distortion of leaf axillary or terminal buds on pedunculate oak (''Quercus robu ...
'') on pedunculate oak
File:Pineapple gall.JPG, Pineapple gall
The Pineapple gall adelgid (''Adelges abietis'') is a type of conifer-feeding insect that forms pineapple-shaped plant galls on its host species, commonly Norway and Sitka spruce. The adelgids (genus ''Adelges'') are pear-shaped, soft-bodied g ...
on Sitka spruce
''Picea sitchensis'', the Sitka spruce, is a large, coniferous, evergreen tree growing to almost tall, with a trunk diameter at breast height that can exceed 5 m (16 ft). It is by far the largest species of spruce and the fifth-larg ...
caused by ''Adelges abietis
The Pineapple gall adelgid (''Adelges abietis'') is a type of conifer-feeding insect that forms pineapple-shaped plant galls on its host species, commonly Norway spruce, Norway and Sitka spruce. The adelgids (genus ''Adelges'') are pear-shaped, ...
''
File:Developing Pineapple Gall.JPG, Developing pineapple pseudocone galls on Norway spruce
''Picea abies'', the Norway spruce or European spruce, is a species of spruce native to Northern, Central and Eastern Europe.
It has branchlets that typically hang downwards, and the largest cones of any spruce, 9–17 cm long. It is very close ...
File:Gall of Japanagromyza inferna in Centrosema virginianum L. - ZooKeys-374-045-g006.jpg, Gall of ''Japanagromyza inferna
''Japanagromyza'' is a genus of leaf miner flies in the family Agromyzidae
The Agromyzidae are a family commonly referred to as the leaf-miner flies, for the feeding habits of their larvae, most of which are leaf miners on various plants.
...
'' in ''Centrosema virginianum
''Centrosema virginianum'' is known by the common names of Spurred Butterfly Pea, wild blue vine, blue bell, and wild pea. ''C. virginianum'' is a member of the family Fabaceae, it is identified by its trailing and twining vine and showy fl ...
''
File:Oakgall3800ppx.JPG, An oak
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
tree with multiple oak apple
Oak apple or oak gall is the common name for a large, round, vaguely apple-like gall commonly found on many species of oak. Oak apples range in size from in diameter and are caused by chemicals injected by the larva of certain kinds of gall ...
s
File:Galle.jpg, Oak apples on an oak tree
File:Eriophyes tilae tilae close up.JPG, Lime nail galls (''Eriophyes tiliae tiliae'')
File:Rhododendron ferrugineum b.JPG, Leaf galls on ''Rhododendron ferrugineum
''Rhododendron ferrugineum'', the alpenrose, snow-rose, or rusty-leaved alpenrose is an evergreen shrub that grows just above the tree line in the Alps, Pyrenees, Jura and northern Apennines, on acid soils. It is the type species for the genus ' ...
''
File:Dasineura investita gall.jpg, ''Dasineura investita
''Dasineura investita'', the wood nettle gall midge, forms a gall that grows on the wood nettle plant '' Laportea canadensis'' It was described in 2016 and is caused by a midge in the family Cecidomyiidae. The galls form on the petiole, upper l ...
'' nettle gall
File:Schizomyia impatientis galls.jpg, '' Schizomyia impatientis'' jewelweed flower gall
File:Pachypsylla celtidisumbilicus gall.jpg, ''Pachypsylla celtidisumbilicus
''Pachypsylla'' is a genus of psyllids. Species of the genus ''Pachypsylla'' lay eggs on the leaves of the ''Celtis occidentalis'' tree. Upon hatching, the young psyllids become encased in a gall which the young leaf parts grow in response to the ...
'' hackberry gall
File:Neolasioptera boehmeriae crop.jpg, ''Neolasioptera boehmeriae
''Neolasioptera boehmeriae'' is a species of gall midges, insects in the family Cecidomyiidae. It is found in the northeastern United States and Southern Canada. False nettles (genus ''Boehmeria
''Boehmeria'' is a genus of 47 species of floweri ...
'' false nettle stem gall
File:Kokkocynips rileyi oak gall crop.jpg, ''Kokkocynips rileyi
''Dryocosmus rileyi'' is a species of gall wasp in the family Cynipidae
Gall wasps, also incorrectly called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they ...
'' oak gall
File:Phylloteras poculum oak gall crop.jpg, ''Phylloteras poculum
''Phylloteras'' is a North American genus of gall wasps in the family Cynipidae,
tribe Cynipini (oak gall wasps).
Species
There are at least 4 described species in ''Phylloteras'',
possibly 11 total.
* ''Phylloteras cupella'' ( Weld)—urn g ...
'' oak galls
File:Gall of peach tree leaves.jpg, Gall on peach tree leaves
File:Bottle Tree Eucalyptus cypellocarpa.jpg, ''Eucalyptus cypellocarpa
''Eucalyptus cypellocarpa'', commonly known as mountain grey gum, mountain gum, monkey gum or spotted mountain grey gum, is a species of straight, smooth-barked forest tree that is endemic to southeastern Australia. It has relatively large, lance ...
'' at The Gap Scenic Reserve
The Gap Scenic Reserve is situated in the state of Victoria in south eastern Australia. It is a small reserve in isolated forest country beside the Bonang Highway. The reserve features tall eucalyptus trees and ferny gullies. Significant tree s ...
, Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
File:Gall attack.JPG, Gall attack on Eucalyptus
''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as euca ...
due to ''Leptocybe invasa
''Leptocybe invasa'', the blue gum chalcid wasp or eucalyptus gall wasp, is a chalcid wasp which is the only species in the monotypic genus ''Leptocybe'' in the subfamily Tetrastichinae, of the family Eulophidae. It is a gall wasp which causes t ...
'' at Acharya N. G. Ranga Agricultural University
Acharya N. G. Ranga Agricultural University (ANGRAU) is a public agricultural university with its headquarters at the village Lam, Guntur district, Andhra Pradesh, India.
History
The original Andhra Pradesh Agricultural University was est ...
File:Actinidia polygama mushi.jpg, Fruit gall on ''Actinidia polygama
''Actinidia polygama'' (also known as , silver vine, , and cat powder) is a species of kiwifruit in the Actinidiaceae family. It grows in the mountainous areas of Korea, Japan and China at elevations between .
Silver vine can reach up to high ...
''
See also
*
Forest pathology
Forest pathology is the research of both Biotic stress, biotic and Abiotic stress, abiotic maladies affecting the health of a forest ecosystem, primarily Fungal infection in plants, fungal pathogens and their insect vectors. It is a subfield of ...
*
Burl
A burl (American English) or burr (British English) is a tree growth in which the grain has grown in a deformed manner. It is commonly found in the form of a rounded outgrowth on a tree trunk or branch that is filled with small knots from do ...
*
Bush coconut
The bush coconut, or bloodwood apple, is an Australian bush tucker food. It is an insect gall with both plant and animal components: an adult female scale insect and her offspring (of genus ''Cystococcus'') live in a gall induced on a bloodwo ...
* ''
Chirosia betuleti
''Chirosia betuleti'' is a species of fly, which causes knotting gall in ferns. The gall develops in the terminal shoots of ferns, such as broad buckler fern (''Dryopteris dilatata''), male fern (''Dryopteris filix-mas''), lady fern (''Athyrium f ...
''
*
Mulga apple
The mulga apple is an Australian bush tucker food, often eaten by the Indigenous Australians of Central Australia.
The mulga apple is in fact a combination of plant and animal; the insect gall grows inside the wood of the mulga tree ''(Acacia a ...
*
Oak apple
Oak apple or oak gall is the common name for a large, round, vaguely apple-like gall commonly found on many species of oak. Oak apples range in size from in diameter and are caused by chemicals injected by the larva of certain kinds of gall ...
*
Oak marble gall
''Andricus kollari'', also known as the marble gall wasp, is a parthenogenetic species of wasp which causes the formation of marble galls on oak trees. Synonyms for the species include ''Cynips kollari'', ''Andricus quercusgemmae'', ''A. minor'', ...
*
Knopper gall
''Andricus quercuscalicis'' is a gall wasp species inducing knopper galls.
Knopper galls develop as a chemically induced distortion of growing acorns on pedunculate oak (''Quercus robur'' L.) trees, caused by gall wasps, which lay eggs in buds w ...
*
Hackberry nipple gall
*
Oak artichoke gall
Andricus foecundatrix (formerly ''Andricus fecundator'') is a parthenogenetic gall wasp which lays a single egg within a leaf bud, using its ovipositor, to produce a gall known as an oak artichoke gall, oak hop gall, larch-cone gall or hop strobi ...
*
Rose bedeguar gall
''Diplolepis rosae'' is a gall wasp which causes a gall known as the rose bedeguar gall, Robin's pincushion, mossy rose gall, or simply moss gall.Darlington, Arnold (1975) ''The Pocket Encyclopaedia of Plant Galls in Colour.'' Pub. Blandford Pres ...
*
Pineapple gall
The Pineapple gall adelgid (''Adelges abietis'') is a type of conifer-feeding insect that forms pineapple-shaped plant galls on its host species, commonly Norway and Sitka spruce. The adelgids (genus ''Adelges'') are pear-shaped, soft-bodied g ...
*
Cola-nut gall
Cola-nut gallsDarlington, Arnold (1975) ''The Pocket Encyclopaedia of Plant Galls in Colour.'' Pub. Blandford Press. Poole. . P. 155. develop as a chemically induced distortion of leaf axillary or terminal buds on pedunculate oak (''Quercus robu ...
* ''
Neuroterus quercusbaccarum
The common spangle gall on the underside of leaves and the currant gall on the male catkins or occasionally the leaves, develop as chemically induced distortions on pedunculate oak (''Quercus robur''), or sessile oak (''Quercus petraea'') trees, ...
'' – common spangle and currant galls
*
Witch's broom
Witch's broom or witches' broom is a deformity in a woody plant, typically a tree, where the natural structure of the plant is changed. A dense mass of shoots grows from a single point, with the resulting structure resembling a broom or a ...
References
Notes
Further reading
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*
*
External links
British Plant Gall Society
*
ttp://www.bio.brandeis.edu/fieldbio/galls/galls.html Insect Galls ''Brandeis University''
Galls in Goldenrod, (''Solidago'')* {{cite web , title=Common oak galls , work=University of Kentucky Entomology , url=http://www.uky.edu/Ag/Entomology/entfacts/trees/ef408.htm , access-date=2006-09-11 , archive-date=2006-09-13 , archive-url=https://web.archive.org/web/20060913044856/http://www.uky.edu/Ag/Entomology/entfacts/trees/ef408.htm , url-status=dead
Video footage of Scottish Galls