Southern Red Mite, Oligonychus ilicis (McGregor) (Arachnida: Acari: Tetranychidae)1
H. A. Denmark, W. C. Welbourn, and T. R. Fasulo2
Introduction
The southern red mite (SRM), Oligonychus ilicis (McGregor) is an important spider mite pest of broad-leaved evergreens. Bolland et al. (1998) reported the SRM from seven countries on four continents and feeding on 34 different plant species in 15 families. The SRM is called the coffee red mite in Brazil.
Adult southern red mites, Oligonychus ilicis (McGregor).
Credit: R.F. Mizell, University of Florida
[Click thumbnail to enlarge.]
Synonymy
Oligonychus ilicis (McGregor) was originally described as Tetranychus ilicis by McGregor 1917, from American holly (Ilex opaca) in South Carolina. McGregor transferred the species to Paratetranychus in 1919, and Pritchard and Baker (1955) placed it in Oligonychus. The holotype is in the U.S. National Museum.
Distribution
The general distribution of the SRM includes the Northern Hemisphere and South America. Although the southern red mite was described in the United States, Pritchard and Baker (1955) suggested it might have originated in the "Far East." Published distribution records includes: Brazil, Italy, Japan, Korea, The Netherlands, Paraguay, and the USA. Although O. ilicis was reported from Australia (Knihinicki et al. 1999), the Australian Department of Agriculture, Fisheries & Wildlife reports it as eradicated (Anonymous 2006).
In the United States the southern red mite has been reported from Alabama, California, Florida, Louisiana, Massachusetts, New Jersey, New York, North Carolina, Ohio, South Carolina, and Virginia. It is probably widespread on broad-leaved evergreens in the eastern United States.
Description and Biology
The adult female is approximately 385 µ (1/50 inch) in length with a rotund-elliptical body. The adult male is approximately 300 µ in length, much less rotund, and narrowed posteriorly. The male aedeagus is shown below. Both sexes are ferruginous to reddish brown, and darker than most red spider mites found on woody ornamentals. It is more translucent towards the front end of the body (Mizell et al. 2002).
Eggs (center), nymphs (right), and adult (left) of the Oligonychus ilicis (McGregor). Photograph by: Jim Baker, North Carolina State University; www.forestryimages.org
[Click thumbnail to enlarge.]
Adult female: dorsal view.
Credit: J.L. Castner, University of Florida
[Click thumbnail to enlarge.]
Male aedeagus.
[Click thumbnail to enlarge.]
Numerous generations occur each year, but population densities are highest during the cooler months of spring and fall during periods of prolonged high humidity. The species overwinters as red eggs on the undersides of the leaves. However, darker, summer eggs can be abundant on preferred hosts when infestations are not controlled .While some mites may be active during the summer months, most of the population is dormant (in aestivation) during the summer heat (Johnson and Lyon 1994).
Hosts
Common hosts are azaleas (Rhododendron spp.) and camellias (Camellia japonica).
Other reported host plants include:
American sycamore, Platanus occidentalis
boxwood, Buxus spp.
camphor tree, Cinnamonum camphora
coffee, Coffea arabica
cotoneaster, Cotoneaster sp.
cranberry, Vaccinium macrocarpon
deer grass or meadow beauty, Rhexia sp.
doghobble, Leucothoe sp.
elaeagnus or silverthorn, Elaeagnus pungens
English walnut, Juglans regia
eucalyptus, Eucalyptus spp.
guava, Psidium guajava
hibiscus, Hibiscus spp.
holley, Ilex spp.
juniper, Juniperus sp.
laurel or bay leaf, Laurus nobilis
loquat, Eriobtrya japonica,
oak, Quercus sp.
pear, Pyrus communis
pecan, Carya illinoensis
photinia or red tip, Photinia spp.
pyracantha, Pyracantha coccinea
rose apple, Syzygium jambos =Eugenia
silkoak, Grevillea robusta
spruce, Picea sp.
summersweet or sweet pepperbush, Clethra alnifolia
tea, Camellia sinensis
viburnum, Viburnum spp.
Economic Importance
This mite feeds primarily on foliage of woody ornamental plants. It is particularly a pest of azaleas and camellias. It usually attacks the lower leaf surface, and as the population increases it will move to the upper surface of the leaves and on to small succulent stems. It injures the leaves causing a graying, stippling or mesophyll collapse, "firing," and defoliation. The leaves may be distorted if infested occurs when they are young and expanding (Johnson and Lyon 1994).
Southern red mite populations are at their peak during the winter months under mild, humid conditions. These mites can be found year round in the landscape, especially on eleagnus and on shaded or stressed pyracantha. Populations in the nursery usually disappear when the new spring growth develops (Mizell et al.2002).
Damage caused by a southern red mite, Oligonychus ilicis (McGregor), infestation on cherry laurel, Prunus laurocerasus L. Photograph by: Frank A. Hale, University of Tennessee; www.forestryimages.orf
[Click thumbnail to enlarge.]
Damage caused by a southern red mite, Oligonychus ilicis (McGregor), infestation.
Credit: J.L. Castner, University of Florida
[Click thumbnail to enlarge.]
Management
Use a 10X to 15X magnifying glass to examine the undersides of the leaves for the mites, cast skins and their webbing. A quicker method that many employ is to place a sheet of white paper or paper plate beneath the leaves and strike the foliage sharply. If mites are present they will fall onto the white surface where they can be more easily seen and identified than on the green foliage.
Three different species of phtyoseiid mites were tested for predation of O. ilicis, with the adult females of the predators exhibing the most predation, preferring O. ilicis larvae over adults (Franco 2007
Florida Insect Management Guide for ornamentals
Selected References
Anonymous. (2006). New Plant Pests and Diseases Recorded in Australia. Australian Government Department of Agriculture, Fisheries and Wildlife.
Bolland HR, Gutierrez J, Flechtmann CHW. 1998. World catalogue of the spider mite family (Acari: Tetranychidae). Brill Academic Publishers, Leiden, 392 pp.
Franco RA, Reis PR, Zacarias MS, Altoé BF. 2007. Predation potential of three species of phytoseiids on Oligonychus ilicis (McGregor, 1917) (Acari: Tetranychidae). Coffee Science 2: 175-187.
Johnson WT, Lyon HH. 1994. Insects That Feed on Trees and Shrubs. An illustrated practical guide. 2nd ed. rev. Cornell University. Press, Ithaca, NY. 560 p.
Knihinicki D, Keskula D, Herron G. (1999). The southern red mite: another new pest. The Nursery Papers.
McGregor EA. 1917. Descriptions of seven new species of red spiders. Proceedings of the U.S. National Museum 51: 581-590.
Mineiro JLC, Sato ME, Raga A, Arthur V, Moraes GJ. Sarreta FO, Carrijo A. 2006. Diversity of mites (Arachnida: Acari) on Coffea arabica L. cv. Mundo Novo in Jeriquara and Garça counties, state of São Paulo. Biota Neotrop. 6: 2.
Mizell RF, Fasulo TR, Short DE. (2002). WoodyBug. UF/IFAS. (http://entomology.ifas.ufl.edu/fasulo/woodypest) (29 January 2010).
Pritchard AE, Baker EW. 1955. A revision of the spider mite family Tetranychidae. Pacific Coast Entomological Society Memorandum 2: 472 p.
Reeves RM. 1963. Tetranychidae infesting woody plants in New York state, and a life history study of the elm spider mite, Eotetranychus matthyessei n. sp. Cornell University Agricultural Experiment Station, Memoir 380: 1-99.
Footnotes
This document is EENY-376 (IN680), originally published as DPI Entomology Circular 79, one of a series of Featured Creatures from the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published July 2006. Reviewed August 2009. Revised December 2009. Reviewed October 2012. This document is also available on Featured Creatures website at http://entomology.ifas.ufl.edu/creatures. Please visit the EDIS website at http://edis.ifas.ufl.edu.
H. A. Denmark and W. C. Welbourn, Florida Department of Agriculture and Consumer Services, Division of Plant Industry; and T. R. Fasulo, Department of Entomology and Nematology, University of Florida, Gainesville, FL32611.
The Institute of Food and Agricultural Sciences (IFAS) is an Equal
Opportunity Institution authorized to provide research, educational
information and other services only to individuals and institutions
that function with non-discrimination with respect to race, creed,
color, religion, age, disability, sex, sexual orientation, marital
status, national origin, political opinions or affiliations.
For more information on obtaining other extension publications,
contact your county Cooperative Extension service.
U.S. Department of Agriculture, Cooperative Extension Service,
University of Florida, IFAS, Florida A. & M. University Cooperative
Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place,
Dean.
