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acari olea eriophyidae australia quarantine
| Scientific name: | Oxycenus maxwelli (Keifer, 1939) (Acari: Eriophyidae) | ||||
| Common Name: | Olive Bud Mite | ||||
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| Identification: | Olive bud mites are extremely small and very difficult to see without magnification. They average in length from 0.1 to 0.2 mm and are yellow to amber in colour, flattened and pear-shaped. They only have two pairs of legs which are located at the front. These mites commonly feed on the upper surfaces of olive leaves but infest the under surfaces when populations are high (Keifer 1939). New buds, shoots, stems and leaves are preferred. | ||||
| Known Hosts: | The only known host is Olea europaea L. (Oleaceae), the olive
tree.
Studies by the University of California (1994) state that Ascolano is the most susceptible variety followed by Sevillano, Manzanillo and Mission. In Australia, the olive bud mite has so far been detected on the varieties Paragon and Barnea in NSW. |
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| Damage: | Overseas, at least nine species of eriophyoid mites belonging to seven genera are known to occur on olives. The most harmful species, in addition to O. maxwelli, are Aceria oleae (Nalepa), Tegolophus hassani (Keifer) and Ditrymacus athiasella Keifer. It is difficult to estimate the amount and type of injury which is caused by each different species because they occur in mixed populations and have similar feeding habits (Castagnoli & Oldfield 1996). However, heavy infestations of O. maxwelli can cause the premature fall of olive flowers, spotting and distortion of leaves (Russo 1972). In nurseries and young plantations, spring and autumn infestations of buds can lead to serious disorders in growth and even block the development of young plants (Castagnoli & Oldfield 1996). | ||||
| Life Cycle: | Generally, overwintering females of O. maxwelli are found on the upper surfaces of leaves. Only about 1 to 4 mites are found per apical leaf at that stage. With the onset of spring, females move to the buds and new leaflets where they start to reproduce rapidly. In a short space of time, all life stages are found. Throughout the flowering stage, individuals migrate to the developing buds, calyx and ovaries. Densities can reach as many as a hundred mites per flower. Individuals then move onto the young fruits. When the fruit reaches more than 0.5 cm in diameter they move to the persistent flower sepals. During summer, olive bud mites return to the leaves and populations decrease again (Castagnoli & Oldfield 1996). | ||||
| Distribution: | Overseas: O. maxwelli is recorded from California, Italy,
Greece, Portugal, Egypt, Armenia and Algeria.
In Australia the species has been found in the Hunter Valley of NSW. |
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| References: | Castagnoli, M. &
Oldfield, G.N. 1996. Chapter 3.2.3. Other fruit trees and nut trees.
In: World Crop Pests, Vol.6, Eriophyoid Mites — Their Biology, Natural
Enemies and Control (eds EE Lindquist, MW Sabelis & J Bruin) pp. 543–559.
Elsevier Science BV, Amsterdam.
Keifer, H.H. 1939. Eriophyid Studies III. Bulletin of the Californian Department of Agriculture 28: 144–162. Russo, L.F. 1972. Oxypleurites maxwelli Keifer (Acarina: Eriophyidae) in Campania. Bollettino del Laboratorio di Entomologia Agraria ‘Filippo Sivestri’ Portici. 30: 165–168. Sibbett, G.S. & Martin, G.C. 1994. Olive Production Manual. University of California, Division of Agriculture and Natural Resources, Oakland, CA. Publication 3353. 160 pp. |
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| Acknowledgements: | Dr Murray Fletcher, of ASCU, assisted with the production of the web page and took photographs of the olive bud mite. | ||||
| Links: | University of California site provides further information and images of Olive Bud Mite. | ||||
Document 8492, submitted 09 October 2000 © NSW Agriculture, 2000 Top of page | Related titles |
