Eriophyid mites in berry crops

The Eriophyidae are unique amongst mites for having only two pairs of legs instead of four. Their shape is elongate, spindle-like, and around 200μm in length. This group of mites constitutes plant feeding organisms with very limited host ranges; some represent prevalent agricultural pests!

In raspberries, leaf and bud mite Phyllocoptes gracilis can cause foliar distortion and chlorosis in association with raspberry leaf blotch virus. In heavy infestations, irregular fruit growth and death of apical buds can occur. At times, the mites will cause conspicuous growth of hairs on affected areas.

Blackberries, on the other hand, can be affected by redberry mite Acalitus essigi. Similarly to leaf and bud mite, the redberry mite overwinters underneath bud scales or axils, migrating to leaves when weather conditions are favourable, and to flowers and fruit as populations increase. Damage appears consequently to the mites feeding at the bases of blackberry drupelets, which interferes with their ripening and causes them to remain red. These symptoms seem to be associated with toxic saliva or the presence of a virus. Berries affected by redberry mite are not marketable.

Mites of the Iolinidae family seem to show promise for the biological control of eriophyid mites in tomatoes, and further research may assess their potential for applications in Rubus crops.

Get in touch with Marco Corradi at Haygrove Chrysalis laboratory for information on how to send samples for identifying eriophyid mites injurious to berry crops.