Galls or cecidia 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 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 insect and mite plant galls. The study of plant galls is known as cecidology.
Celtis is a genus of about 60–70 species of deciduous trees, commonly known as hackberries or nettle trees, widespread in warm temperate regions of the Northern Hemisphere. The genus is part of the extended Cannabis family (Cannabaceae).
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 (oligophagous). Together with aphids, phylloxerans, scale insects and whiteflies, they form the group called Sternorrhyncha, which is considered to be the most "primitive" group within the true bugs (Hemiptera). They have traditionally been considered a single family, Psyllidae, but recent classifications divide the group into a total of seven families; the present restricted definition still includes more than 70 genera in the Psyllidae. Psyllid fossils have been found from the Early Permian before the flowering plants evolved. The explosive diversification of the flowering plants in the Cretaceous was paralleled by a massive diversification of associated insects, and many of the morphological and metabolic characters that the flowering plants exhibit may have evolved as defenses against herbivorous insects.
In biology, a lerp is a structure of crystallized honeydew produced by larvae of psyllid bugs as a protective cover. These animals are commonly referred to as lerp insects, of which there are over 300 species in Australia.
Coextinction and cothreatened refer to the phenomena of the loss or decline of a host species resulting in the loss or endangerment of an other species that depends on it, potentially leading to cascading effects across trophic levels. The term originated by the authors Stork and Lyal (1993) and was originally used to explain the extinction of parasitic insects following the loss of their specific hosts. The term is now used to describe the loss of any interacting species, including competition with their counterpart, and specialist herbivores with their food source. Coextinction is especially common when a keystone species goes extinct.
Citrus greening disease or yellow dragon disease is a disease of citrus caused by a vector-transmitted pathogen. The causative agents are motile bacteria, Liberibacter spp. The disease is transmitted by the Asian citrus psyllid, Diaphorina citri, and the African citrus psyllid, Trioza erytreae, also known as the two-spotted citrus psyllid. It has no known cure. It has also been shown to be graft-transmissible.
Celtis occidentalis, commonly known as the common hackberry, is a large deciduous tree native to North America. It is also known as the nettletree, sugarberry, beaverwood, northern hackberry, and American hackberry. It is a moderately long-lived hardwood with a light-colored wood, yellowish gray to light brown with yellow streaks.
Celtis laevigata is a medium-sized tree native to North America. Common names include sugarberry, southern hackberry, or in the southern U.S. sugar hackberry or just hackberry.
"Candidatus Carsonella ruddii" is an obligate endosymbiotic Gammaproteobacterium with one of the smallest genomes of any characterised bacteria.
Celtis tenuifolia, the dwarf hackberry or Georgia hackberry is a shrub or small tree 2-to-12-metre-high. It is native to eastern North America but is very uncommon north of the Ohio River. In Canada, dwarf hackberry is designated as threatened and protected under Canada's Species at Risk Act.
Bactericera cockerelli, also known as the potato psyllid, is a species of psyllid native to southern North America. Its range extends from Central America north to the American Pacific Northwest and parts of Manitoba, in Canada. It is restricted to the western part of the continent. As its name suggests, it is commonly found on potato and tomato crops, but has a species range that encompasses over 40 species of solanaceous plants and as many as 20 genera. Breeding hosts are generally recognised as being restricted primarily to Solanaceae, including important crop and common weed species, and a few species of Convolvulaceae, including bindweed and sweet potato. On some plants, especially potato, feeding of the nymphs causes a condition called psyllid yellows, presumed to be the result of a toxin. Both nymphs and adults can transmit the bacterium Candidatus Liberibacter.
Asterocampa celtis, the hackberry emperor, is a North American butterfly that belongs to the brushfooted butterfly family, Nymphalidae. It gets its name from the hackberry tree upon which it lays its eggs. The hackberry tree is the only host plant for A. celtis and is the food source for larvae.
Celtis reticulata, with common names including netleaf hackberry, western hackberry, Douglas hackberry, netleaf sugar hackberry, palo blanco, and acibuche, is a small- to medium-sized deciduous tree native to western North America.
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 infestation.
Diaphorina citri, the Asian citrus psyllid, is a sap-sucking, hemipteran bug in the family Psyllidae. It is one of two confirmed vectors of citrus greening disease. It has a wide distribution in southern Asia and has spread to other citrus growing regions.
Liberibacter is a genus of Gram-negative bacteria in the Rhizobiaceae family. Detection of the liberibacteria is based on PCR amplification of their 16S rRNA gene with specific primers. Members of the genus are plant pathogens mostly transmitted by psyllids. The genus was originally spelled Liberobacter.
Asterocampa leilia, the Empress Leilia, Leilia hackberry butterfly or desert hackberry, is a species of butterfly in the family Nymphalidae.
Torymus pachypsyllae is a species of Torymid wasp found in North America. It primarily attacks the psyllid Pachypsylla celtidismamma, although it is known to attack other related species in the genus Pachypsylla.
