Molecular detection of cyclamen mite (Phytonemus pallidus) in strawberry

Cyclamen mite, Phytonemus pallidus (Banks) (Trombidiformes: Tarsonemidae), is a widespread pest of strawberry, feeding on new growth, and causing stunted plants and damaged fruit. Because of its small size (~0.25 mm) and cryptic lifestyle, cyclamen mite is often undetected until populations are high and damage is readily apparent. The objective of our research was to develop a PCR-based method for detecting cyclamen mite from strawberry leaf samples.

Cyclamen mite was collected from eight fields in Ontario and Quebec, Canada, and a sequence library of the barcoding region of the cytochrome oxidase subunit I (COI) gene was created using the Lep F/R primer pair. Sequences were assembled and aligned in Geneious Prime. A primer set for a 94 bp amplicon was designed and tested by amplifying cyclamen mite DNA that had already been successfully sequenced with end-point PCR and visualizing bands on a 5% agarose gel. Primer selectivity was determined by non-amplification of DNA from 20 arthropods that are known to occur on strawberry. Primer sensitivity was determined by amplifying decreasing concentrations of cyclamen mite DNA. Future experiments will be conducted to determine if these primers are compatible with direct PCR and qPCR methods. The outcome of this project will be a new method capable of detecting cyclamen mite at low population levels.