This article is about the abnormal growths in plants and animals. For early uses, see Gall ( disambiguation ) Kalanchoe infected with Agrobacterium tumefaciens. A crown bile oninfected with Apiocrinites negevensis) from the Middle Galls can besides appear on bony animals and in the dodo record. Two galls with perforations on a crinoid stem ( ) from the Middle Jurassic of southerly Israel
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gall from a Jade Plant ( Crassula ovata ) Galls ( from Latin galla, ‘oak-apple ‘ ) or cecidia ( from Greek kēkidion, anything gushing out ) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths [ 1 ] of establish tissues, like to benign tumors or warts in animals. They can be caused by diverse parasites, from viruses, fungi and bacteria, to other plants, insects and mites. Plant galls are much highly organized structures so that the cause of the saddle sore can much be determined without the actual agent being identified. This applies peculiarly to some insect and touch plant galls. The analyze of plant galls is known as cecidology. In human pathology, a chafe is a raised sensitive on the hide, normally caused by chafing or rubbing. [ 2 ]
Causes of plant galls [edit ]
Insects and mites [edit ]
Sectioned oak marble resentment showing cardinal “ cell ”, inquiline chamber, and exit-hole with a possibly parasitised stunted saddle sore specimen. Insect galls are the highly distinctive plant structures formed by some herbivorous insects as their own microhabitats. They are implant tissue which is controlled by the worm. Galls act as both the habitat and food source for the godhead of the saddle sore. The interior of a resentment can contain comestible alimentary starch and other tissues. Some galls act as “ physiologic sinks ”, concentrating resources in the bile from the encompassing plant parts. [ 3 ] Galls may besides provide the worm with forcible protection from predators. [ 4 ] [ 5 ] Insect galls are normally induced by chemicals injected by the larva of the insects into the plants, and possibly mechanical damage. After the galls are formed, the larva develop inside until amply grown, when they leave. In order to form galls, the insects must take advantage of the time when plant cell division occurs promptly : the growing season, normally leap in temperate climates, but which is extended in the tropics. The meristem, where plant cell division occurs, are the usual sites of galls, though worm galls can be found on other parts of the plant, such as the leaves, stalks, branches, buds, roots, and even flowers and fruits. Gall-inducing insects are normally species-specific and sometimes tissue-specific on the plants they gall .
indicator insects [edit ]
Gall-inducing insects include gall wasp, bile midges, gall flies ( for example, the goldenrod crust fly ), Agromyzidae, aphids ( such as Melaphis chinensis, Pemphigus spyrothecae, and Pemphigus betae ), scale insects, psyllids, thrips, bile moths ( for example, Epiblema scudderiana ), and weevils. [ 6 ] Galls produced by insects and mites include :
- 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 15–25 mm (
–1 in) 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 cockscomb gall: these distinct galls, caused by an aphid, are about 25 mm (1 in) long and about 5 mm (
in) 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 (2.5 mm or
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in 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 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 (5 mm or
in 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
- 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 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. 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.
Fungi [edit ]
many rust fungi induce gall formation, including western chafe rust, which infects a kind of ache trees and cedar-apple rust. Galls are often seen in Millettia pinnata leaves and fruits. Leaf galls appear like bantam clubs ; however, flower galls are ball-shaped. Exobasidium often induces outstanding galls on its hosts. The fungus Ustilago esculenta associated with Zizania latifolia, a wild rice, produces an comestible gall highly valued as a food source in the Zhejiang and Jiangsu provinces of China. [ 7 ]
Bacteria and viruses [edit ]
Agrobacterium tumefaciens and Pseudomonas savastanoi are examples of gall-causing bacteria. Gall forming virus was found on rice plants in central Thailand in 1979 and named rice resentment shadow. Symptoms consisted of saddle sore formation along leaf blades and sheaths, dark green stain, twist leaf tips and deoxidize numbers of tillers. Some plants died in the greenhouse in late stages of infection. The causal agent was transmitted by Nephotettix nigropictus after an incubation of two weeks. polyhedral particles of 65 new mexico 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 shadow .
Nematodes [edit ]
Nematodes are microscopic worms that live in the land. Some nematodes ( Meloidogyne species or root-knot nematodes ) cause galls on the roots of susceptible plants. The galls are small, individual and beady in some hosts. In other plant species galls may be massive accumulations of fleshy tissue more than 25 millimeter ( 1 in ) in diameter. Some ectoparasitic nematodes ( nematodes that live outside the plant in the land ), such as sting and stubby-root nematodes, may cause ancestor tips to swell. nitrogen-fixing bacteria ( Rhizobium 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 etymon and their contents. Nodules are broadly attached to the beginning, while root-knot galls originate from infection at the center of the solution, so they are an built-in separate of the root. In addition, fresh rhizobium nodules have a milky pink-to-brown fluid inside them, while root-knot galls have firmer tissues and contain female root-knot nematodes ( creamy white beads less than 1 millimeter or 1⁄32 in in diameter ) inside the resentment tissues. [ citation needed ]
other plants [edit ]
Mistletoe can form galls on its hosts .
Uses [edit ]
Galls are deep in resins and tannic acerb and have been used in the fabrication of permanent wave inks ( such as iron crust ink ) and astringent ointments, in dye, and in tanning. The Talmud [ 8 ] records using gallnuts as share of the tanning serve angstrom well as a dye-base for ink. chivalric Arabic literature records many uses for the gall, called ˁafṣ in Arabic. The Aleppo crust, found on oak trees in northerly Syria, was among the most authoritative exports from Syria during this menstruation, with one merchant recording a dispatch of galls from Suwaydiyya near Antioch fetching the eminent price of 4½ dinars per 100 pounds. The primary use of the galls was as a mordant for black dyes ; they were besides used to make a high-quality ink. The bile was besides used as a medicine to treat fever and intestinal ailments. [ 9 ] The larva in galls are utilitarian for a survival food and fishing tease ; see the Indigenous Australian foods Bush coconut and Mulga apple. Nutgalls besides produce purpurogallin. The bile of Rhus chinensis, Galla chinensi, has long been considered to possess many medicative properties. [ 10 ]
gallery [edit ]
See besides [edit ]
References [edit ]
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- Blanche, Rosalind (2012). Life in a Gall: The Biology and Ecology of Insects that Live in Plant Galls. Collingwood, Vic.: CSIRO Publishing. ISBN 978-0643106437.
- Redfern, Margaret (2011). Plant Galls. London: Collins. ISBN 978-0002201445.
- Russo, Ron (2007). Field Guide to Plant Galls of California and Other Western States. Berkeley, Calif.: Univ. of California Press. ISBN 9780520248854.