Estimation of shiso rust mite occurrence by loop-mediated isothermal amplification assay

For the quantification of shiso rust mite (Shevtchenkella sp.) occurrence, which is difficult to be observed because of their tiny body size, a loop-mediated isothermal amplification (LAMP) assay was tested. Shiso rust mites on leaves were collected by rinses with ethanol. DNA was extracted from the washing solution and the LAMP assay was carried out using a specific primer set. This method enabled shiso rust mites detection from approximately 18% of the perilla mosaic diseased 116 strain. In addition, shiso rust mites in the air were collected using a wet trap. DNA was extracted from the trapping liquid and the LAMP reaction performed. The time during which turbidity increased was measured using a real-time turbidimeter, and it enabled to detect the peak of the occurrence of mites. Determination of the number of shiso rust mites scattered in the air revealed that they rapidly increase from July to September.