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Aceria zeala(Keifer)

A mite new to North America has been found in a California greenhouse

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Name: Aceria zeala (Keifer)
Taxonomic Position:
Animalia: Arthropoda: Arachnida: Acari: Eriophyidae
Common Names: corn eriophyd mite

Aceria zeala was discovered in large numbers in a California greenhouse in July, 2001. This represents the first report of this potentially serious pest of corn in North America.

Issues of Concern: The known infestation in California has been eradicated, and the greenhouse where the mites were found was cleaned and heat-treated. Potential surrounding hosts, corn and sorghum, were inspected and no mites were found. Surveys will continue, however, in case the infestation originated from or spread to surrounding areas.

This mite is a member of a widespread group of grass-infesting species and was originally described from corn in Columbia in 1978. It infests both sides of the leaves as they project from the husk. Infested plants display yellowish streaks on the blades, but in field situtations few plants are usually affected. It is currently unknown whether the yellow streaking results from feeding damage alone or is associated with a virus.

Little is known about the biology and life-history of A. zeala. This mite is wind-dispersed and experts are concerned that it could be a serious pest on corn, affecting husk formation and pollenization; that it may act as a vector of the high plain virus or some other, possibly new virus; and that it may be able to transfer viruses from wheat to corn. Studies are being conducted to find out more about this pest's distribution, host range and pest potential.

Pathways: Aceria zeala may have been imported into California on corn plants from South America that were intended for research.

Hosts: Corn (Zea mays L.)


Detection Strategies
Aceria zeala is close to Eriophyes zeasinis (K.) 1962 (see photos), but differs by lacking a central cross line on the propodosomal shield, by the featherclaws having a 5-6-ray arrangement (zeasinis has 6-rayed featherclaws), and by the flatter microtubercles. Female yellowish-white; body length from anterior point of propodosomal shield to terminal lobes 210µ-250µ; thickness about 48. Body wormlike in shape. Gnathosome comparatively short, curved down, 23 long; antapical seta 5 long. Shield 39 long by 42 wide, subtriangular in dorsal view. Shield design of longitudinal lines composed of short dashes with fine connections. Median line present on rear half of shield and somewhat broken. Admedian lines complete, sinuate, gradually diverging to rear margin. A line of dashes just inside dorsal tubercle. First submedian line from anterior point of shield, extending toward dorsal tubercle but turning outward ahead of tubercle. Second submedian from anterior edge of shield, diverging from first submedian, and ending at rear margin lateral to tubercle. Side of shield with rather broad band of granules above coxae and longitudinal line within this band; two or three partial rings below tubercle. Foreleg from trochanter base about 33 long; tibia 51/2 long, with 10 long seta from about 1/2; tarsus 7.5 long; claw 10 long, tapering; featherclaw 5-6 rayed, 5 on outside. Hindleg 30 long, tibia 6 long, tarsus 6 long, claw 10 long, featherclaw 5-6 rayed. Sternal line between forecoxae moderately long, ending between second coxal tubercles. Coxae generally with lines of short dashes, a line from first coxal tubercle extending back to just inside of second tubercle. First setiferous coxal tubercles even with front end of sternal line and farther apart than second tubercles. Second coxal tubercles in line across third tubercles. Abdominal thanosome with about 70-75 rings; rings completely microtuberculate the microtubercles somewhat linear, flattened, mostly ahead of rear ring margins except dorsally and midventrally. Lateral seta 30 long, on ring 8 behind shield; first ventral seta 41 long, on ring 24; second ventral seta 14 long on ring 45. Abdominal telosome with 5 rings; microtubercles fine, linear and touching margins, longer below. Telosomal seta 20 long. Accessory seta 3 long. Female genitalia 17 long by 21 wide, deep bowl-shaped; 9-11 ribs on coverflap; internal anterior apodeme of moderate anterior length. Genital seta 16 long. Male 170-185 long.

An earlier name used for this species was Eriophyes zealus .

For questions and help with identification, contact Jim Amrine at or Ron Ochoa at

Amrine, J.W., Jr. and T.A. Stasny. 1994. Catalog of the Eriophyoidea (Acarina: Prostigmata) of the world. Indira Publishing House, West Bloomfield, Michigan, USA. 798 pp.

Baker EW, T Kono, JW Amrine Jr, M Delfinado-Baker, and TA Stasny 1996 Eriophyoid mites of the United States. Indira Publishing House, West Bloomfield, Michigan. pp 1-394.

Davis R, CHW Flechtmann, JH Boczek, and HF Barke 1982 Catalogue of Eriophyid Mites (Acari: Eriophyoidea), Warsaw Agricultural University Press, Poland, pp. 1-254.

Keifer, H.H. 1978. Eriophyid Studies C-15. U.S. Department of Agriculture, Agricultural Research Service, 24 p.p.

Warning: The information in this archived item was not confirmed with the appropriate National Plant Protection Organization and is provided solely for informational purposes. Please use this information with caution.

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