Aculus cornutus

Aculus cornutus (Banks)

{(known also as Aculus fockeui (Nalepa and Trouessart)}

Taxonomic placing: Acari, Prostigmata, Eriophyoidea, Eriophyidae.

Common name: Silver peach mite.

Geographical distribution: Almost wherever peaches are grown. In the Middle East known since the late 1980s.

Host plants: Stone fruit trees (Rosaceae), including almonds, apricots, nectarines, plums and prunes.

Morphology: The mite is spindle-shaped, yellowish, about 0.18 mm in length, with a pair of backwards-pointing prodorsal setae. The dorsal shield bears several parallel ridges that are more pronounced in the deutogynes, which is also somewhat larger. The opisthosoma has about 30 dorsal and 50 ventral rings. The featherclaw is four-rayed.

Life history: The mite is a leaf vagrant, overwintering around the host’s terminal buds as deutogynes, which appear in the autumn, and molt to protogynes next spring. A life cycle is completed in about a fortnight, and 15-20 annual generations may be raised. Like other Eriophyidae, reproduction is by arrhenotoky; the males deposit spermatophores that are taken up by the females. Fecundity is host-determined, as the mite produced 40 eggs/female on plum, only 30 on sour cherry. The mite is inactive below 20°C and by 33°C the adults begin to slow down and cease their activities. The protogynes of the peach silver mite differ in some morphological from the deutogynes, and were formerly described as a different species.

Economic importance: The feeding of the peach silver mite causes silvering of peach foliage late in the season as well as yellow chlorotic spots on young leaves. In heavy infestations the leaves curl and may drop, plant growth is retarded and yield is affected.

Management

Monitoring: Examination of new terminal growth for browning.

Chemical control: Acaricides in common usage against the pest include bromopropylate (Neoron), chlorobenzilate and abamectin. The peach silver mite is not affected by pyrethroids and applications of these compounds abroad have resulted in pest resurgences, probably due to killing its natural enemies.

Biological control: Abroad the pest has several efficient natural enemies of the family Phytoseiidae, but nothing is known about them in the Middle East.

References

Abou-Awad, B.A., AL-Azzazy, M.M. and El-Sawi, S.A. 2010. The life – history of the peach silver mite, Aculus fockeui (Acari: Eriophyidae) in Egypt. Archives Of Phytopathology And Plant Protection 43: 384-389.

Boczek, J., Zawadski, W. and Davis, R. 1984. Some morphological and biological differences in Aculus fockeui (Nalepa and Trouessart)` (Acari: Eriophyidae) on various host plants. International Journal of Acarology 10: 81-87.

Kondo, A. and Hiramatsu, T. 1999. Resurgences of the peach silver mite, Aculus fockeui (Nalepa and Trouessart) (Acari: Eriophyidae), induced by a synthetic pyrethroid fluvalinate. Applied Entomology and Zoology 34: 531-535.

Sternlicht, M. and Rubin, A. 1990. The peach silver mite, a new pest in Israel. Ha’Sadeh 70: 910-912 (in Hebrew with an English summary).

Websites: https://www.google.co.il/search?q=Aculus+cornutus&espv=2&biw=1536&bih=854&tbm=isch&tbo=u&source=univ&sa=X&ved=0CBoQsARqFQoTCJm4ltTG0MgCFYfxFAod3QIKNw

http://www.ipm.ucdavis.edu/PMG/r602400211.html