''Cecidophyopsis ribis'' is an eriophyid

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evid ...

which is best known for being a plant parasite, a pest of ''

Ribes ''Ribes'' is a genus of about 200 known species of flowering plants, most of them native to the temperate regions of the Northern Hemisphere. The various species are known as currants or gooseberries, and some are cultivated for their edible f ...

'' species, the genus that includes

gooseberries Gooseberry ( or (American and northern British) or (southern British)) is a common name for many species of '' Ribes'' (which also includes currants), as well as a large number of plants of similar appearance. The berries of those in the gen ...

and blackcurrants. It is commonly known as the blackcurrant gall mite or big bud mite. It feeds on the plants' buds, forming

galls Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) 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 be ...

, and transmits a virus which causes blackcurrant reversion disease. The mite is a serious pest of blackcurrant crops in Europe, but rarely on other continents.

Biology

Buds affected by ''Cecidophyopsis ribis'' become swollen and globular and fail to develop normally. They are first noticeable in the autumn when they are unpointed and twice as large as normal buds. Inside the bud, between the closely folded leaves, are thousands of small, spherical

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

s which later hatch into sausage-shaped mites with short legs near their anterior end. The mites suck sap from the buds and while they are doing so, can transmit the

virus A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's ...

that causes blackcurrant reversion disease. The mites are long. When mature they move out of the buds onto the twigs where they make their way to uninfested buds or may feed on the foliage later in the season causing distortion of the leaves. Crop yields are reduced as a result of the damage they do. The mites are so tiny that they can easily be blown or splashed onto other bushes or carried inadvertently by flying insects. They breed during the summer and autumn, laying their eggs inside new buds. They can also infest the buds of gooseberries, whitecurrants or

redcurrant The redcurrant or red currant (''Ribes rubrum'') is a member of the genus ''Ribes'' in the gooseberry family. It is native to western Europe. The species is widely cultivated and has escaped into the wild in many regions. Description ''Ribes r ...

s, but in these the affected buds die and "big bud" symptoms do not develop. These alternative host fruit bushes are not susceptible to blackcurrant reversion disease.

Blackcurrant reversion disease

The virus causing blackcurrant reversion is transmitted by ''Cecidophyopsis ribis''. The characteristic leaf symptoms are a smaller number of leaf lobes and a decrease in the number of teeth on the serrated edge of the leaves. The flowers also show symptoms, with the buds being less hairy than normal and, in a severe form of the disease present in Russia and Scandinavia, the

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined ...

s appearing to be doubled in number to ten. The vigor of the bush is reduced, and fruit yields diminish. Although spread of the mite can be prevented to some extent, badly affected bushes should be destroyed and replaced with virus-free stock. Until 2019 the virus was found everywhere blackcurrants grew except

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the C ...

and Australia. However in 2019 it was detected for the first time in

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. ...

USA The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territo ...

. Although these mites are the only known vector, the mites themselves have not been found. It is unknown whether something else is vectoring the pathogen or if this evidences another transmission route is working in this area.

Distribution

''Cecidophyopsis ribis'' is found mainly in Europe and

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

, but has also reached

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island country ...

. It is not found in

or Australia and

quarantine A quarantine is a restriction on the movement of people, animals and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have been ...

restrictions apply to the import of susceptible plants.

References

{{Taxonbar, from=Q2185581 Eriophyidae Animals described in 1869 Arachnids of Europe Galls Taxa named by John O. Westwood