Galls (from the Latin galla, 'oak-apple') or cecidia (from the Greek kēkidion, anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or warts in animals. They can be caused by various parasites, from viruses, fungi and bacteria, to other plants, insects and mites. Plant galls can be such highly organized structures that their cause can be determined without the actual agent being identified. This applies particularly to insect and mite plant galls. The study of plant galls is known as cecidology.
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👉 Gall in the context of Phylloxera
Grape phylloxera is an insect pest of grapevines worldwide, originally native to eastern North America. Grape phylloxera (Daktulosphaira vitifoliae (Fitch 1855) belongs to the family Phylloxeridae, within the order Hemiptera, bugs); originally described in France as Phylloxera vastatrix; equated to the previously described Daktulosphaera vitifoliae, Phylloxera vitifoliae. The insect is commonly just called phylloxera (/fɪˈlɒksərə/; from Ancient Greek: φύλλον, leaf, and ξηρός, dry).
These almost microscopic, pale yellow sap-sucking insects, related to aphids, feed on the roots and leaves of grapevines (depending on the phylloxera genetic strain). On Vitis vinifera, the resulting deformations on roots ("nodosities" and "tuberosities") and secondary fungal infections can girdle roots, gradually cutting off the flow of nutrients and water to the vine. Nymphs also form protective galls on the undersides of grapevine leaves of some Vitis species and overwinter under the bark or on the vine roots; these leaf galls are typically only found on the leaves of American vines.
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Gall in the context of Mite
Mites are small arachnids (eight-legged arthropods) of two large orders, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari. However, most recent genetic analyses do not recover the two as each other's closest relative within Arachnida, rendering the group invalid as a clade. Most mites are tiny, less than 1 mm (0.04 in) in length, and have a simple, unsegmented body plan. The small size of most species makes them easily overlooked; some species live in water, many live in soil as decomposers, others live on plants, sometimes creating galls, while others are predators or parasites. This last type includes the commercially destructive Varroa parasite of honey bees, as well as scabies mites of humans. Most species are harmless to humans, but a few are associated with allergies or may transmit diseases.
The scientific discipline devoted to the study of mites is called acarology.
Gall in the context of Oak
An oak is a hardwood tree or shrub in the genus Quercus of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisphere, with some 500 species, both deciduous and evergreen. Fossil oaks date back to the Middle Eocene. Molecular phylogeny shows that the genus is divided into Old World and New World clades, but many oak species hybridise freely, making the genus's history difficult to resolve.
Ecologically, oaks are keystone species in habitats from Mediterranean semi-desert to subtropical rainforest. They live in association with many kinds of fungi including truffles. Oaks support more than 950 species of caterpillar, many kinds of gall wasp which form distinctive galls (roundish woody lumps such as the oak apple), and a large number of pests and diseases. Oak leaves and acorns contain enough tannin to be toxic to cattle, but pigs are able to digest them safely. Oak timber is strong and hard, and has found many uses in construction and furniture-making. The bark was traditionally used for tanning leather. Wine barrels are made of oak; these are used for aging alcoholic beverages such as sherry and whisky, giving them a range of flavours, colours, and aromas. The spongy bark of the cork oak is used to make traditional wine bottle corks. Almost a third of oak species are threatened with extinction due to climate change, invasive pests, and habitat loss.
Gall in the context of Eurosta solidaginis
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 goldenrod, genus. The fly's eggs are inserted near the developing buds of the plant. After hatching, the larvae migrate to an area below the plant's developing buds, where they then induce the plant's tissues to form into the hardened, bulbous chamber referred to as a gall. E. solidaginis’s interactions with its host plant(s) and insect, as well as avian, predators have made it the centerpiece of much ecological and evolutionary biology research, and its tolerance of freezing temperatures has inspired studies into the anti-freeze properties of its biochemistry.
Gall in the context of Rosette (botany)
In botany, a rosette is a circular arrangement of leaves or of structures resembling leaves.
In flowering plants, rosettes usually sit near the soil, but they can also be at the top of an otherwise leafless branch or trunk. Their structure is an example of a modified stem in which the internode gaps between the leaves do not expand, so that all the leaves remain clustered tightly together and at a similar height. Some insects induce the development of galls that are leafy rosettes.
Gall in the context of Gall wasp
Gall wasps, also traditionally called gallflies, or cynipids, 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 cynipids are known worldwide, with about 360 species of 36 different genera in Europe and some 800 species in North America. Diplolepididae were traditionally included within the Cynipidae but have since been designated as their own family after some more recent phylogenetic studies.
Gall in the context of Oak apple
An oak apple or oak gall is a large, round, vaguely apple-like gall commonly found on many species of oak. Oak apples range in size from 2 to 4 centimetres (1 to 2 in) in diameter and are caused by chemicals injected by the larva of certain kinds of gall wasp in the family Cynipidae.