''Aceria chondrillae'' (chondrilla gall mite, skeletonweed gall mite) is a gall forming deuterogynous,

eriophyid Eriophyidae is a family of more than 200 genera of mites, which live as plant parasites, commonly causing galls or other damage to the plant tissues and hence known as gall mites. About 3,600 species have been described, but this is probably ...

(mite) often used as a

biological control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also i ...

of the noxious weed, ''

Chondrilla juncea ''Chondrilla juncea'' is a species of flowering plant in the family Asteraceae known by a number of common names, including rush skeletonweed, gum succory, devil's grass, and nakedweed. The plant is native to Europe, Asia, and North Africa, but ...

'' (Rush skeletonweed), a highly competitive herbaceous perennial composite found in Europe, Asia, Australia and North America.Krantz, G.W. and Ehrensing, D.T. (1990). ‘Deuterogyny in the Skeleton Weed Mite, Aceria Chondrillae (G. Can.) (Acari: Eriophyidae)’, International Journal of Acarology, Vol. 16, No 3, pp 129-133.

Biological description

At maturity, mites are yellowish orange in colour, with females ranging from 0.19-0.26 mm in length with the males slightly smaller at, 0.165-0.180 mm.Powell G.W., Sturko A., Wikeem B.M., Harris P. (1994). ‘Field Guide to the Biological Control of Weeds in British Columbia’, British Columbia Ministry Forest Research Program Land Management, pp. 55-56. Except for genitalia male and female mites are externally similar. Larvae are smaller than the adults and distinguished by a humpback and exhibit no external genitalia. Eggs are soft, round, 0.04mm in diameter and at first colorless but later light orange. Mite growth and development is dependent on environmental and climatic conditions.Caresche, L. A. and Wapshere, A. J. (1974). ‘Biology and host specificity of the Chondrilla gall mite Aceria chondrillae (G. Can.) (Acarina, Eriophyidae)’, Bulletin of Entomological Research, 64, pp 183-192. ''A. chondrillae'' have an average generation cycle of 10 days.

Impact on chondrilla

The chondrilla plant exhibits galls when infested by ''A. chondrillae''. These galls appear as clusters of tiny, hyperplastic buds reaching a size of 1.5–2 cm in diameter, and in some cases up to 5 cm. Hundreds of mites can be contained within each gall. The development of the galls impede the health, growth, and reproduction abilities of the plant by: * destroying the flower buds in gall formation, reducing and suppressing seed production. * compromising the apical shoots, resulting in a diminished regenerative capacity. Particularly efficacious in plants infested early, gall formations block shoot development on the apical growing points, stunting growth, distorting adjacent stems, associated foliage and in some cases causing death. * weakening the plant through the presence and production of large galls. The plant often turns yellow early from premature decline. ''A. chondrillae'' has been recognized to affect plants of the Chondrilla genus: ''C. juncea'', ''C. juncea f. acantholepis'', ''C. brevirostris'' and ''C. leiosperma''. Skeletonweed gall mite 0022094-PPT

Use as a biological control

''Aceria chondrillae'' is often used as a

for the perennial herb skeleton weed (''Chondrilla juncea'') present in Europe, North America and Australia. It was introduced to Australia in 1971 as part of a program to suppress skeleton weed in areas where it dominates the landscape.Cullen, J. M. and Moore, A. D. (1983). ‘The Influence of Three Populations of Aceria chondrillae on Three Forms of Chondrilla juncea’, Journal of Applied Ecology, Vol. 20, No. 1, pp. 235-243.

Predators

Only one predator of the Chondrilla gall mite has been observed in nature. The

Phytoseiid The Phytoseiidae are a family of mites which feed on thrips and other mite species. They are often used as a biological control agent for managing mite pests. Because of their usefulness as biological control agents, interest in Phytoseiidae has ...

predatory mite, '' Amblyseius sp.'', lives in the galls made by ''Aceria chondrillae'' and exists in all Mediterranean areas where ''Aceria chondrillae'' has been found. Populations are small and have little effect on ''A. chondrillae'' numbers.

References

{{Taxonbar, from=Q4673204 Eriophyidae Invasive plants biological control agents Arachnids of Asia Animals described in 1891