Propagation of Ditylenchus destructor on garlic storage leaf

Abstract

Ditylenchus destructor is a plant-parasitic nematode that negatively impacts upon garlic production in Japan. It feeds not only on plant cells but also on fungi; hence, fungal infection of garlic plants may also potentially affect nematode propagation. In the present study, we assessed whether or not the nematode could propagate on garlic storage leaves under fungus-free conditions, and thereby cause garlic rot. We detected propagation of nematodes at 4 weeks after the inoculation of axenic nematodes onto surface sterilized garlic storage leaves of Fukuchi white, the major garlic variety cultivated in Japan. In further tests, the nematodes propagated on 16 garlic varieties by 8 weeks post-inoculation, but propagation levels were significantly lower in varieties from southwest Japan, such as Hirado and Iki, than in the varieties Ishikawa roppen and Fukuchi white. Moreover , the garlic storage leaves on which the nematodes propagated most successfully became rotten. These results suggest that D. destructor can propagate on garlic storage leaves and cause garlic rot without the influence of fungal infection.