Plant Feeding Mites

 

​Eriophyoidea

​More than 6 000 species of plant feeding (phytophagous) mites are known worldwide. The majority of plant feeding species belong to the obligate plant parasitic Eriophyoidea (e.g. gall mites, erinose mites, bud mites, rust mites) and Tetranychoidea (e.g. spider mites, false spider mites), while a number of species belong to other lineages (e.g. Eupodoidea, Tarsonemidae, and single oribatid mites).

​ ​​Parasitic Mites Predatory Mites Arachnida Research

 Plant feeding mites form an integral and important part of the natural ecosystem. Some species, especially eriophyoid mites, can be utilised for the biological control of weeds. Many plant feeding mites are of economic importance as pests of crop plants. In South Africa about 65 species cause damage to agricultural crops and ornamental plants.  

• All eriophyoid mites are plant feeding. They are extremely tiny, the majority are less than 300 micron long, and essentially invisible to the unaided eye. They have elongated, worm-like bodies, with only two pairs of legs.

• Eriophyoid mites are commonly known as gall mites, bud mites, rust mites, erineum mites, witches' broom mites, blister mites and so on, referring to the symptoms caused by a particular species. The feeding of almost half of eriophyoid species known, though, does not cause visible damage to their plant hosts.

• The eriophyoid mites belong to three families: Phytoptidae, Eriophyidae and Diptilomiopidae. About 3 400 species are known, but these probably represent only as little as 5% or less of extant eriophyoid species. Most woody and many herbaceous flowering plants, and gymnosperms and ferns most likely host these minute mites. Most eriophyoid species are highly host specific, restricted to one or single closely related plant species.

• In South Africa 25 eriophyid species are regarded as pests.

• Many research activities currently in progress at the ARC-PPRI Arachnology Unit's Acari Section concern this fascinating and economically important group of microscopic organisms.

List of eriophyid mites (Acari: Eriophyoidea: Eriophyidae) regarded as pests in South Africa

In South Africa 25 eriophyid species are regarded as pests.

1. Abacarus hystrix (Nalepa) (cereal rust mite)
2. Aceria aloinis (Keifer) (aloe wart mite or aloe gall mite)
3. Aceria barbertoni Meyer & Ueckermann (Gerbera erineum mite)
4. Aceria cynodoniensis Sayed (Bermuda grass stunt mite or grass rosette mite)
5. Aceria diastolus Meyer & Ueckermann (Cape leadwort leafroll mite)
6. Aceria ficus (Cotte) (fig bud mite)
7. Aceria granati (Canestrini & Massalonga) (pomegranate leafroll mite or pomegranate leafcurl mite)
8. Aceria mangiferae Sayed (mango bud mite)
9. Aceria merwei (Tucker) (on sugarcane)
10. Aceria oleae (Nalepa) (olive bud mite)
11. Aceria proteae Meyer (Protea witches' broom mite)
12. Aceria sheldoni (Ewing) (citrus bud mite)
13. Aceria tulipae (Keifer) (tulip bulb mite or bulb eriophyid mite)
14. Aceria tumisetus Meyer & Ueckermann (Gazania gall mite)
15. Aculops lycopersici (Tryon) (tomato rust mite)
16. Aculus fockeui (Nalepa & Trouessart) (peach silver mite)
17. Calacarus capsica Chakrabarti & Mondal (pepper purple mite)
18. Calacarus carinatus (Green) (purple tea mite)
19. Calacarus citrifolii Keifer (grey citrus mite or citrus grey mite)
20. Colomerus spathodeae (Carmona) (African flame erineum mite or tulip tree erineum mite)
21. Colomerus vitis (Pagenstecher) (grape gall mite, grape bud mite, grape erinose mite or grape blister mite)
22. Epitrimerus pyri (Nalepa) (pear rust mite)
23. Eriophyes pyri (Pagenstecher) (pear bud mite or pear leaf blister mite)
24. Phyllocoptruta oleivora (Ashmead) (citrus rust mite)
25. Phytoptus hedericola Keifer (ivy bud mite)

Research Activities

The following research projects are in progress:

• A systematic appraisal of the Eriophyoidea, including cladistic analyses.

• The description of a new Phyllocoptruta sp., in collaboration with R. Ochoa of USDA-ARS, Beltsville, USA.

• The description of a new species collected on Rhus lancea in South Africa.

• Systematic study on eriophyoid mites (mostly Trisetacus spp.) collected on conifers in France, in collaboration with ARC-PPRI Weeds research. (Read more about mites as control agents of weeds)

• Systematic study on eriophyoid mites (mostly Aceria spp.) collected on Polygalaceae in South Africa and Australia in collaboration with R. Adair, ARC-PPRI Weeds research, Stellenbosch. (Read more about mites as control agents of weeds)

Tetranychoidea (spider mites and their relatives)

 All tetranychoid mites are obligate plant feeders, and many species are well-known agricultural pests. The Tetranychoidea comprises five families:

1. TETRANYCHIDAE (spider mites)

This family is a large group of plant feeding mites (about 1 200 species known worldwide), and can probably be regarded as the most important family in the Acari regarding members that are pests of agricultural crops and other plants. In southern Africa about 26 species are regarded as pests.

The spider mites have round to oval-shaped bodies, and are as large or smaller than a pin head (about 0.3 to 0.8 mm long). Their colour vary: green, red, brown, yellow, orange, black or combinations of any of these, depending on the species and the life stage.

Most tetranychid species have a wide host range, other than the generally more host specific Eriophyoidea. Some species, especially Tetranychus spp., can produce extensive webbing which impedes effective control of these pests. Chemical control of spider mites is also compounded by development of resistance to acaricides.

2. TENUIPALPIDAE (false spider mites or flat mites)

The false spider mites are very small (females about 0.2 - 0.4 mm long) (smaller than the spider mites) and somewhat flattened, and are difficult to see with the naked eye. They are usually reddish or brown red. They move relatively slowly and lie very flat against the plant surfaces.  Tenuipalpid mites appear to be best adapted to subtropical or tropical regions. Members of the genera Brevipalpus, Tenuipalpus and Dolichotetranychus are of particular importance as plant pests. In southern Africa, four species are regarded as pests of economic importance:

Brevipalpus californicus (Banks) (citrus flat mite)
Brevipalpus obovatus Donnadieu (ornamental flat mite)
Brevipalpus phoenicis (Geijskes) (reddish black flat mite)
Dolichotetranychus floridanus (Banks) (pineapple flat mite)

3. TUCKERELLIDAE

The family Tuckerellidae consists of about 20 described species worldwide. All belong to the single genus, Tuckerella. Tuckerella ornata (Tucker) was originally described from citrus in South Africa.

4. ALLOCHAETOPHORIDAE and
5. LINOTETRANIDAE

List of Tetranychoidea: Tetranychidae mites (Acari) regarded as pests in southern Africa

In southern Africa about 26 Tetranychoidea species are regarded as pests.  

1. Bryobia neopraetiosa Meyer (brown lucerne mite)
2. Bryobia praetiosa Koch (brown clover mite)
3. Bryobia rubrioculus (Scheuten) (brown fruit tree mite or bryobia mite)
4. Eotetranychus falcatus Meyer & Rodrigues (cotton green mite)
5. Eotetranychus lewisi (McGregor) (poinsettia spider mite)
6. Eutetranychus orientalis (Klein) (Lowveld citrus mite or Oriental mite)
7. Meyernychus emeticae (Meyer) (Angolan citrus mite)
8. Mononychellus tanajoa (Bondar) (cassava green mite)
9. Mononychellus progresivus Doreste (cassava green mite)
10. Oligonychus coffeae (Nietner) (red tea mite)
11. Oligonychus mangiferus (Rahman & Sapra) (mango red mite)
12. Panonychus citr (McGregor) (citrus red mite)
13. Panonychus ulmi (Koch) (European red mite)
14. Petrobia latens (Müller) (brown wheat mite or onion mite)
15. Schizotetranychus asparagi (Oudemans) (asparagus mite)
16. Tetranychina harti (Ewing) (oxalis mite)
17. Tetranychus amicus Meyer & Rodrigues (African spider mite or banana mite)
18. Tetranychus evansi Baker & Pritchard (tobacco spider mite)
19. Tetranychus hydrangeae Baker & Pritchard (hydrangea spider mite)
20. Tetranychus lombardinii Baker & Pritchard (crimson spider mite)
21. Tetranychus ludeni (dark-red spider mite or red-legged spider mite)
22. Tetranychus neocaledonicus André (vegetable spider mite)
23. Tetranychus rooyenae Meyer (cotton spider mite)
24. Tetranychus turkestani Ugarov & Nikolski (Turkish spider mite)
25. Tetranychus urticae Koch (common spider mite or two-spotted spider mite)
26. Tetranychus zambezianus Meyer & Rodrigues

Research activities 

• Several applied research activities currently concern the control of spider mites and other plant feeding mites on tomatoes, see APPLIED ACAROLOGY for more information.
• Also see COURSES, PRODUCTS AND EXTENSION for more information about a new handbook on mites of ornamental flowers which Dr. Lenie Smith Meyer, a research associate at the unit, is writing at the moment. Dr. Meyer laid the foundation for research on especially the Tetranychoidea of Africa, and the world.

Identification and information services

We identify Tetranychoidea on a continuous basis, and receive specimens for identification from various sources, nationally and internationally. The identification service plays an important role in phytosanitary matters.

Dr. M.K.P. Meyer (Smith) Research associate at the Arachnida unit

The late Dr. Meyer was an internationally acknowledged specialist in the taxonomy of phytophagous mites, especially the Tetranychoidea. Her expertise, however, extends to various other groups, and also encompasses mite bio-ecology, and she was especially an authority on plant feeding mites of agricultural importance.

Her contributions She has made an enormous contribution to Acarology in Africa in describing more than 700 new species and 25 new genera, mostly mites of agricultural importance. She has published more than a 100 scientific papers, including seven Entomological Memoirs (total of 1032 pages), and a handbook on mites on vegetables and berries (90 pages). One of her major contributions was in the Tetranychidae (spider mites) and the Tenuipalpidae (false spider mites) on which she published 11 scientific papers, and four Entomological Memoirs. The four memoirs alone total 807 pages. She is also regarded as one of the specialists on the Eriophyoidea, and described 181 new species in 24 scientific papers. She also described and published new species of 16 other mite families, and four super families. She initiated the National Collection of Mites (now the National Collection of Arachnida), an identification service and systematic mite surveys in South Africa. The first check list of Acari of the Ethiopian Region has been compiled by her, and she organised surveys of mites of economically importance on various crops in several countries in southern Africa, and provided the first list of the 60 most important mite pest species in this region. She made an important contribution towards the control of mites on different crops and published papers on mites on citrus, cotton, deciduous fruit, grapes, berries, vegetables, field crops, pastures, tobacco, and ornamental plants. She further developed collecting techniques for Acari, especially in applied Acarology, and made a great input in the correct use of spraying equipment in the chemical control of mites. In the information service on the control of mites she provided, she made a special effort to promote the biological control of mites with predatory mites, spiders and insects. She made an important contribution in assisting the then Plant and Quality Control of the Department of Agriculture to prevent the accidental introduction of foreign mite species on plant material and fruit to South Africa. Dr. Meyer was actively involved in the registration of new acaricides (Act 1936/1947). She assisted chemical firms with the planning and layout of their spray trials on different crops and assisted the Registrar in the evaluation of the data. Her training She finished her high school training by matriculating at the Helpmekaar Hoër Meisieskool in Johannesburg, South Africa. She continued her education by obtaining a B.Sc. (Botany and Zoology) degree cum laude at the University of Potchefstroom for CHE, and later an M.Sc. degree in Zoology at the same university. She proceeded, and already started making history, by being the first woman at this university to obtain her doctoral degree in zoology, and she did it cum laude in 1959. Simultaneously she also finished a Higher Diploma in Librarianship (again cum laude) in 1958. Her M.Sc. thesis is titled: "Some parasitoid mites associated with South African beetles", and the D.Sc. thesis: "A survey of the prostigmatic mites (Acarina: Trombidiformes: Prostigmata) associated with plants in South Africa, with description of a new genus and 43 new species." Apart from her formal training in South Africa, Dr. Meyer also undertook postgraduate studies in Canada with a bursary from the Canadian Research Council. Her career as acarologist (she was also a librarian before becoming an acarologist) She was the first acarologist in the Department of Agriculture of South Africa, appointed in 1959 to the then Division of Entomology. Her entire career as an acarologist was undertaken at ARC-PPRI, from 1959 to 1994 when she retired. Since then she has been a Research Associate at this institute. There were many highlights during her career, apart from her enormous contributions to acarology, to name but a few: In 1964 she became the head of the subdivision Economic Zoology (Arachnology, Nematology and Mammology) She was promoted to Assistant-Director in 1970 in 1989 she became one of the first researchers in PPRI to become a Specialist Scientist and was further promoted to Senior Specialist Scientist in 1989   Collaboration with other scientists Dr. Meyer's international recognition is illustrated by the collaborative projects she has undertaken with other scientists and the contribution she has made to other countries in assisting them by identifying their mites. She was a co-worker with researchers from Costa Rica, Israel, Netherlands and Portugal She identified mites for: Australia, Belgium, Brazil, Canada, Cape Verde Islands, England, Germany, Hawaii, India, Iran, Malagasy Republic, Netherlands, Reunion, Thailand and the USA She was invited by the governments of Angola, Malawi, Mozambique, Swaziland and Zimbabwe to advise them on economical important mites on different crops On invitation she published articles on the mite fauna of Cameroon, Cape Verde Islands, Costa Rica, Israel, Zimbabwe and Yemen. Post graduate students Dr. Meyer went out of her way to help in the training of young scientists in South Africa. She acted as co-supervisor of four M.Sc. and seven D.Sc. students, and she served as external examiner of six M.Sc. and 8 D.Sc. theses. Refereeing of scientific papers and editorial duties Dr. Meyer refereed numerous articles for the following journals: Acarologia, International Journal of Acarology, African Plant Protection, Australian Journal of Scientific Research, African Entomology, Biologia, Gallo-hellenica, Israel Journal of Entomology, Koedoe, Phytophylactica and others. She has served on the editorial board of the International Journal of Acarology since 1980, and was appointed as one of the main editors of this journal in 1997.

Mites as control agents of weeds