Galls or cecidia 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 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 some insect and mite plant galls. The study of plant galls is known as cecidology.
Thrips are minute, slender insects with fringed wings and unique asymmetrical mouthparts. Entomologists have described approximately 6,000 species. They fly only weakly and their feathery wings are unsuitable for conventional flight; instead, thrips exploit an unusual mechanism, clap and fling, to create lift using an unsteady circulation pattern with transient vortices near the wings.
The gall adelgid is an adelgid species that produces galls in spruce trees. They infect the new buds of native spruce trees in the foothills of the Rocky Mountains in the spring. They also attack blue spruce to a lesser degree. The insects complete two generations within the year. They require two different trees for its life cycle, the second being the Rocky Mountain Douglas-fir. They may also attack Sitka, Engelmann, or white spruce. The many different species of adelgids produce different galls on different spruce species.
Aceria chondrillae is a gall forming deuterogynous, eriophyid (mite) often used as a biological control of the noxious weed, Chondrilla juncea, a highly competitive herbaceous perennial composite found in Europe, Asia, Australia and North America.
Aceria malherbae is a species of gall mite known as the bindweed gall mite. It is used as an agent of biological pest control on invasive species of bindweed, particularly field bindweed.
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, A. indigenus and A. circulans.
Andricus foecundatrix 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 strobile The gall develops as a chemically induced distortion of leaf axillary or terminal buds on pedunculate oak or sessile oak trees. The larva lives inside a smaller hard casing inside the artichoke and this is released in autumn. The asexual wasp emerges in spring and lays her eggs in the oak catkins. These develop into small oval galls which produce the sexual generation of wasps. A yew artichoke gall caused by the fly Taxomyia taxi also exists, but is unrelated to the oak-borne species. Previous names or synonyms for the species A. fecundator are A. fecundatrix, A. pilosus, A. foecundatrix, A. gemmarum, A. gemmae, A. gemmaequercus, A. gemmaecinaraeformis and A. quercusgemmae.
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. The gall develops as a chemically induced distortion of an unopened leaf axillary or terminal bud, mostly on field rose or dog rose shrubs. The female wasp lays up to 60 eggs within each leaf bud using her ovipositor. The grubs develop within the gall, and the wasps emerge in spring; the wasp is parthenogenetic with fewer than one percent being males.
Aceria is a genus of mites belonging to the family Eriophyidae, the gall mites. These tiny animals are parasites of plants. Several species can cause blistering and galls, including erineum galls. A few are economically significant pests, while others are useful as agents of biological pest control of invasive plants such as rush skeletonweed, creeping thistle, and field bindweed.
Aceria sheldoni, commonly called the citrus bud mite, is a species of mite belonging to the family Eriophyidae. It feeds in leaf- and flower-buds of Citrus spp., causing deformation to leaves, flowers and fruit, and is a worldwide pest of citrus fruit production.
Aceria guerreronis, the coconut mite, is an eriophyid mite which infests coconut plantations. It is economically devastating, and can destroy up to 60% of coconut production. The immature nuts are infested and injured by mites feeding in the portion covered by the perianth of the immature nut.
Aceria anthocoptes, also known as the russet mite, rust mite, thistle mite or the Canada thistle mite, is a species of mite that belongs to the family Eriophyidae. It was first described by Alfred Nalepa in 1892.
The Pineapple gall adelgid is a type of conifer-feeding insect that forms pineapple-shaped plant galls on its host species, commonly Norway and Sitka spruce. The adelgids are pear-shaped, soft-bodied green insects with long antennae, closely related to the aphid. Adelges lays up to one hundred eggs at a time, one on each needle. Adelges abietis is one of the most common species; synonyms are A. gallarum-abietis, Chermes abietis and Sacciphantes abietis.
Phytoptus avellanae is an acarine gall-mite species inducing big bud galls of up to 10 millimetres (0.39 in) across, sometimes slightly open, on the buds of hazel and on filbert. Synonyms include Phytocoptella avellanae, Eriophyes avellanae, Calycophthora avellanae, Phytoptus coryli, Phytoptus pseudogallarum, and Acarus pseudogallarum. The mites are white, about 0.3 mm long, with numerous tergites and sternites. Two forms of P. avellanae exist, a gall causer and a vagrant form that has a more complex life-cycle and does not form galls.
Biorhiza pallida is a gall wasp species in the family Cynipidae. This species is a member of the tribe Cynipini: the oak gall wasp tribe. Cynipini is the tribe partially responsible for the formation of galls known as oak apples on oak trees. These are formed after the wasp lays eggs inside the leaf buds and the plant tissues swell as the larvae of the gall wasp develop inside. This wasp has a widespread distribution within Europe.
Aceria fraxinivora, also known as the cauliflower gall mite and the ash key gall, causes the growths, known as galls, found on the hanging seeds or "keys" of the ash (Fraxinus) species.
Aculops fuchsiae, commonly known as fuchsia gall mite, is a species of mite in the family Eriophyidae. It feeds on Fuchsia plants, causing distortion of growing shoots and flowers. It is regarded as a horticultural pest.
Deraeocoris brevis is a species of predatory plant bug in the family Miridae. It is native to North America where it feeds on plant pests in apple and pear orchards.
Aceria fraxini, the ash bead gall mite, is a species of mites in the family Eriophyidae, the gall mites.
