Study on methods for staining root-knot nematodes using different dyes

Root knot nematodes are important pathogens for a great number of crops. These pests reduce yield and quality in crop production. In this study, seven different dyes were tested to stain the larvae infecting initially the host roots, the egg masses produced by adult females, to describe the perineal pattern of female larva tail, and to distinguish alive from dead larvae. The methods will be suitable to recognize the morphology of pathogens in infecting stage. It was shown that the bromophenol blue solution had the best tinting effect to stain the larvae in the root. For staining of egg masses and the perineal pattern around female vulva cochenillerot A or phloxine B solution can be recommended. Died J2 larvae were distinguished from living larvae by using methyl blue solution or acridine orange solution under microscope and visible or fluorescent light, respectively.