Open field cultivation in warm regions often results stem blight (Phomopsis asparagi Sacc.) damage of asparagus (Asparagus officinalis L.).Therefore, the rain protected asparagus cultivation in a plastic house has been developed in Nagasaki Prefecture, Japan in 1987 for the purposes of high yield and disease-control.The occurrence of stem blight could be controlled by the rain protected cultivation of green asparagus.Annual yields are increased dramatically by mother fern culture after harvesting spring spears, but air temperature in plastic houses used for forced or protected cultivation often becomes too high during the summer season.