スマートフォンに装着した市販精子観察キットによるトマトの葉かび病とすすかび病の野外診断

抄録

Leaf mold (pathogen: Passalora fulva) and Cercospora leaf mold (Pseudocercospora fuligena), fungal diseases of tomato leaves, have very similar symptoms, while the conidiophores are morphologically distinguished. Therefore, an accurate diagnosis requires observing the conidiophores with a biological microscope. This paper proposed an in-field diagnosis method of both diseases through microscopic observation of their conidiophores by a commercially available sperm observation kit (product name: Men’s Loupe, TENGA Healthcare Inc.) attached to the camera lens of a smartphone. Among the kit components, two types of oval magnetic sheets (“Loupe” with a 550× ball lens in the center and “Plate” with a hole in the edge) were used. The loupe was attached to a smartphone so that the ball lens’s center overlapped the camera lens’s center. Conidiophores were collected from diseased leaf with cellophane tape. The plate with the cellophane tape covering the hole was magnetically attached to the loupe. Conidiophores were observed launching a camera application on the smartphone. The above method had the same diagnosis accuracy for both diseases as a biological microscope.