Brevipalpus californicus

Brevipalpus californicus Banks

Taxonomic placing: Acari, Prostigmata, Tetranychoidea, Tenuipalpidae.

Common name: Citrus flat mite.

Geographical distribution: Almost cosmopolitan.

Host plants: This mite has been collected from over 300 host plants, but the recent discovery of several cryptic species that masquerade under the specific name californicus suggests that the host list (and biological as well as morphological data) should be amended.

Morphology: The body is oblong, red, about 0.25-0.30 mm in length. The entire dorsum is covered by reticulations. The opisthosoma bears 7 pairs of very short lateral setae and tarsus II has two distal sensory setae (solenidia).

Life history: This mite is slow-moving and usually reproduces by parthenogenesis. Development from egg to first egg requires about 30 days. Females on oranges or lemons produced 15-33 progeny, dependent on the Egyptian climate, and completed 11 annual generations, were thus present throughout the year. The populations peak in mid-summer and favour the eastern parts of the canopy, the lower branches and frequently the fruits, whereon they occur in larger populations on oranges than on mandarins.

Symptoms and economic importance: This cosmopolitan mite feeds on the above-ground parts of all citrus species and varieties, preferring limes and bitter oranges. On fruits the mite often occurs in rind depressions. Feeding results in leaves with yellow-brown spots around puncture wounds and in the skins of fruits, that tend to crack at the damaged sites, causing downgrading. Heavy infestations may result in leaf drop. In South Africa B. californicus produces brownish irregular scab-like spots on the rind of sweet oranges and corky blemishes on Valencia oranges. In Greece it is a serious pest, causing silvering of lemons and mandarins, and a brown speckling of oranges. Other species of Brevipalpus are vectors of viral citrus diseases, but in the Mediterranean Region B. californicus is not known to transmit such diseases.

Management: As this mite is often regarded as a secondary pest in the Mediterranean Region, usually no special control measures are necessary, because rational horticultural practices and pesticides used against other pests usually suffice. In Egypt the need to control B. californicus is stronger, and it is recommended that acaricides (e.g. avermectin and petroleum oils) should be applied, before August, to the lower tree levels and to their eastern aspects. Mite outbreaks on lemons were observed in Egypt after applications of organophosphorus pesticides.

Biological control: Releases of the phytoseiid predator Euseius scutalis (Athias-Henriot) in groups of 50/tree on orange trees in Egypt resulted in about 90% control.

References

Beard, J.J., Ochoa, R., Bauchan, G.R., Trice, M.D., Redford, A.J., Walters, T.W. and Mitter, C. 2012. Flat Mites of the World. Edition 2. Identification Technology Program, CPHST, PPQ, APHIS, USDA; Fort Collins, CO.

Childers C.C., French, J.V. and Rodrigues J.C.V. 2003. Brevipalpus californicus, B. obovatus, B phoenicis, and B. lewisi (Acari: Tenuipalpidae): a review of their biology, feeding injury and economic importance. Experimental and Applied Acarology 30: 5-28.

Childers C.C. and Derrick K.S. 2003. Brevipalpus mites as vectors of unassigned rhabdoviruses in various crops. Experimental and Applied Acarology 30: 1-3.

Jeppson, L.R., Keifer, H.. and Baker, E.W. 1975. Mites Injurious to Economic Plants. University of California Press, pp. 614.

Vacante V. and Gerson, U. (eds) 2011. Integrated Cotrol of Citrus Pests in the Mediterranean Region. Bentham E-book, Science Publishers.

Websites:

https://www.google.co.il/search?q=brevipalpus+californicus&biw=1280&bih=687&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwja4J6wsKvKAhWD1RoKHYJCDDEQsAQIJw