Disease Cycle of Blast of Ginger and Mioga Caused by Pyricularia zingiberi Nishikado.

Abstract

Blast disease (Pyricularia zingiberi Nishikado) occurred on mioga and ginger plants, but not on plants such as Indian shell-flower (Alpinia japonica Miq.), ginger lily (Hedychium coronarium Koen.) and turmeric (Curcuma longa L.) which were growing around ginger fields. The blast fungus overwintered with sclerotium-like structures on the residues of diseased ginger and mioga plants. The overwintered sclerotium-like structures in ginger fields were killed by soil fumigation with methyl bromide which is commonly used before ginger planting season. The primary infection source of ginger plants seemed to be diseased mioga plants, because the first blast development occurred on the latter at the beginning of July, and then continually on the former.