MOLECULAR ECOLOGY OF SOME CECIDOPHYOPSIS MITES (ACARI, ERIOPHYIDAE) ON RIBES SPECIES AND EVIDENCE FOR THEIR NATURAL CROSS COLONIZATION OF BLACK-CURRANT (R-NIGRUM)

Ribosomal DNA from Cecidophyopsis mites from different Ribes species w as amplified using the polymerase chain reaction and the products dige sted using restriction enzymes. After separating the DNA fragments on gels, it was possible to identify specimens of mites obtained from fie ld samples by comparing the profiles of their DNA banding patterns wit h those of known Cecidophyopsis species. Using this analysis, a non-ga ll forming mite found infesting blackcurrant buds in New Zealand was i dentified as the gooseberry mite (C. grossulariae). On wild red curran t (Ribes spicatum) from Finland showing two sizes of galled buds, the red currant gall mite (C. selachodon) was identified in the larger gal ls located at the tips of branches and a distinct mite in the smaller galls located on the lower parts of the branches. A mite with a DNA ba nding profile indistinguishable from this latter mite from R. spicatum was also identified in galled buds of blackcurrant genotypes growing in Finland, including those containing the blackcurrant gall mite (C. ribis)-resistance genes P or Ce. The DNA banding profile of this mite resembled most closely that of C. ribis, but was distinct from it. The occurrence of C. grossulariae and this distinct Cecidophyopsis mite o n blackcurrant has implications for the genetic control of Cecidophyop sis mites and possibly for the spread of the reversion disease agent i n this crop.