Florists' Review Vol. XCII No. 2382
During the past season, three diseases of callas came to the attention of the Illinois Natural History Survey, Urbana, as causing considerable losses in Illinois greenhouses. These were root rot, caused by the fungus Phytophthora cryptogea, var. Richardiae; soft rot, caused by the bacterium Erwinia aroidea, and spotted wilt, caused by a virus which probably is the tomato spotted wilt virus. Root rot, in general, is the most serious disease of callas and can be responsible for losses of entire plantings in a single season. Plants affected with root rot are checked in growth and their leaves turn yellow and die. They produce few or no flowers. Flowers, if produced, are small and of low quality. Severely affected plants can be lifted easily from the soil, because the roots have been destroyed. Newly affected roots appear water-soaked and are soft and mushy. The infection, as it grows older, reduces the roots to soft, papery sheaths, destroying the inner portion, but leaving much of the outer covering intact.
Source: • Florists' Review Vol. XCII No. 2382
Keywords: Root rot Calla lily Disease prevention Greenhouse production Soft rot Spotted wilt