Nalepella | |
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Nalepella danica | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Chelicerata |
Class: | Arachnida |
Order: | Trombidiformes |
Family: | Phytoptidae |
Genus: | Nalepella Keifer, 1944 |
Nalepella, the rust mites, is a genus of very small Trombidiform mites in the family Phytoptidae. [1] [2] They are commonly found on a variety of conifers, including hemlock, spruce, balsam fir, and pine. [2] [3] [4] [5] They sometimes infest Christmas trees in nurseries. [2] [4] Nalepella mites are vagrants, meaning they circulate around the tree; females overwinter in bark cracks. [4] [6] Infested spruce emit a characteristic odour. [7]
The genus is holarctic, and species are found in North America, Europe, and China. [1] [8]
The mites feed on the cell sap of the tree's needles, sometimes causing severe damage. [4] Typical effects from a Nalepella infestation include needle discolouration and premature needle drop. [2] [6] The colour of discolouration varies by species; for example, Nalepella tsugifoliae causes yellowed or grey discolouration, while Nalepella halourga's discolouration is more bronze in colour. [6] [9] Some species are considered serious pests of ornamental coniforous trees. [10] They are commonly found on Christmas trees in North America and Europe, and they may seriously damage the tree. [2]
Spruce infested by Nalepella were found to increase emissions of certain compounds that may cause the characteristic smell of infested plants. [7] Another study in 2009 found that some compounds emitted by infected spruce attracted or repelled Hylobius abietis, another pest of conifers. [11]
Nalepella mite eggs overwinter on needles, then hatch early in the spring. [2] [12] As cold-season mites, they are most active in the early spring and the fall. [2] [12] The mites deposit eggs during the fall, but may continue to be active into the winter. [2] They have multiple generations per year. [12]
N. brewrieanae, first discovered in 2003 on Picea breweriana . [14] It was first described from Germany, but is also known from Poland. [14] [22] Besides P. breweriana, it is also known from P. abies and P. glauca . [22] [23]
Nalepella danica infests members of the Abies (fir) genus. Specifically, it has been recorded from A. alba, A. concolor , A. lasiocarpa, and A. nordmanniana. [22] [24] [25] It causes small rusty brown to bronze spots on the needles of its host plant, but a severe infestation can result in defoliation. [22] [25] Nymphs typically grow between 90 and 108 μm, while female adults 145 and 240 μm. [25] They are known exclusively from Denmark. [24] [25]
Nalepella ednae is distributed across the central and Northwestern United States, as well as in British Columbia. [26] They are of concern in Mexico, where they may be introduced via cut Christmas trees. [26] [27] [28] Although it is only known from a few fir species, all may be hosts. [26] The damage they cause is unknown. [22] [29]
Nalepella haarlovi is known from Denmark and Finland. [8] It has been recorded infesting Picea sitchensis . [30] They are one of the most economically important members of the genus. [8] This species has four to eight generations per year. [8]
Nalepella halourga, commonly known as the spruce rust mite, is restricted to Picea (spruce). [2] Their colour varies throughout the year; during the growing season, they are colourless to pale yellow, but in the fall they turn reddish-purple. [9] They are found in Eastern North America. [8]
Nalepella longoctonema was first described in 1991 from two fir species in Oregon. [31] [32] They grow to 206 μm in length, and have been collected in large numbers on fir plantations. [8] They are one of the most economically important members of the genus. [8]
Nalepella shevtchenkoi lives around the bases of the host plant's needles, as well as on its stems. [22] [33] It is known from Abies (fir) and Picea (spruce) species. [22] The species is considered one of the most damaging of the eriophyoid mites. [22] It is found in parts of central and eastern Europe. [34] [35]
The hemlock rust mite is reddish-orange in colour, and has relatively large eggs. [36] They infest fir, hemlock, larch, and yew to high densities- there may be as many as 100 mites on one needle. [2] [6] [37] Infested trees turn bluish, then yellow, before beginning to drop needles. [38] They feed on both sides of the tree's needles. [39]
A spruce is a tree of the genus Picea, a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. Picea is the sole genus in the subfamily Piceoideae. Spruces are large trees, from about 20 to 60 m tall when mature, and have whorled branches and conical form.
Mites are small arachnids. Mites span two large orders of arachnids, 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 non-monophyletic. 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.
Picea breweriana, known as Brewer spruce, Brewer's weeping spruce, or weeping spruce, is a species of spruce native to western North America, where it is one of the rarest on the continent. The specific epithet breweriana is in honor of the American botanist William Henry Brewer.
The blue spruce, also commonly known as green spruce, Colorado spruce, or Colorado blue spruce, is a species of spruce tree native to North America in Arizona, Colorado, Idaho, New Mexico, Utah and Wyoming. It is noted for its blue-green colored needles, and has therefore been used as an ornamental tree in many places far beyond its native range.
The Fraser fir, sometimes spelled Frasier fir, is an endangered species of fir native to the Appalachian Mountains of the Southeastern United States. They are endemic to only seven montane regions in the Appalachian Mountains.
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.
Abacarus hystrix, the cereal rust mite or grain rust mite, belongs to the family Eriophyidae. They are extremely small with adults measuring up to 1 millimetre in length and only have four legs at the front of the body. Viewing by the human eye requires a 10 – 20X lens. The adult mites are usually yellow but also have been seen to be white or orange. The cereal rust mite was first found on Elymus repens, a very common perennial grass species. It has now been found on more than 60 grass species including oats, barley, wheat and ryegrass, found in Europe, North America, South Africa and Australia. Mites migrate primarily through wind movement and are usually found on the highest basal sections of the top two leaf blades. Abacarus hystrix produces up to twenty overlapping generations per year in South Australian perennial pastures, indicating that the species breeds quite rapidly. It has been noted that the cereal rust mite can cause losses in yield of up to 30-70%.
Aberoptus is a genus of mites belonging to the family Eriophyidae. These tiny mites, flattened in shape, live beneath the waxy layer on the underside of the leaves of certain plants.
Pine and fir trees, grown purposely for use as Christmas trees, are vulnerable to a wide variety of pests, weeds and diseases. Many of the conifer species cultivated face infestations and death from such pests as the balsam woolly adelgid and other adelgids. Aphids are another common insect pest. Christmas trees are also vulnerable to fungal pathogens and their resultant illnesses such as root rot, and, in the U.S. state of California, sudden oak death. Douglas-fir trees in particular are vulnerable to infections from plant pathogens such as R. pseudotsugae.
Eriophyoidea are a superfamily of herbivorous mites. All post-embryonic instars lack the third and fourth pairs of legs, and the respiratory system is also absent.
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 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.
The pineapple gall adelgid is a species 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.
Aceria tosichella, commonly known as the wheat curl mite (WCM), is a global cereal pest and a vector for spreading and transmission of viruses like wheat streak mosaic virus (WSMV) and wheat mosaic virus (WMoV)
Spruce broom rust or yellow witches' broom rust is a fungal plant disease caused by the basidiomycete fungus known as Chrysomyxa arctostaphyli. It occurs exclusively in North America, with the most concentrated outbreaks occurring in northern Arizona and southern Colorado on blue and Engelmann spruce, as well as in Alaska on black and white spruce. This disease alternates its life cycle between two hosts, with the spruce serving as the primary host and bearberry serving as the secondary or alternate host. The name for the disease comes from the distinctive “witches broom”, commonly yellow in color, which forms on the spruce after young needles have been infected. Management must be carried out through physical or mechanical methods, such as the pruning of brooms or the removal of the secondary host from the area, because no chemical control measures have yet been determined to be economically effective. Generally, spruce broom rust is seen as a mostly cosmetic issue, and it is very rarely the direct cause of tree death; however, research has shown a reduction in overall productivity and health of infected trees, making it an important issue for logging and timber companies.
Arceuthobium pusillum is a perennial, obligate parasitic plant in the sandalwood family. Its common names include Dwarf mistletoe or Eastern dwarf mistletoe. It is one of the most widespread dwarf mistletoes within its range which covers the eastern United States and Canada, from Saskatchewan to Nova Scotia and New Jersey. The species name "pusillum" derives from Latin "pusillus", meaning very small.
Elatobium abietinum, commonly known as the spruce aphid or green spruce aphid, is a species of aphid in the subfamily Aphidinae that feeds on spruce, and occasionally fir. It is native to Northern, Central and Eastern Europe and has spread to Western Europe, North America and elsewhere.
Cryphalus piceae, the small fir bark beetle, is a tiny bark beetle, about 1.7 mm long that is found in central and southern Europe. It infests mainly fir (Abies) and spruce trees (Picea) and occasionally can cause damage to branches and young trees, including tree death.
Fiorinia externa, the elongate hemlock scale was accidentally introduced into North America from Japan and is now established in most parts of the north-eastern U.S. It has become a serious pest of hemlock (Tsuga) and some related conifers from the family Pinaceae. Dense colonies of the scale insect result in yellowing, shedding of leaves, dieback and occasional tree death.