Erysiphe cichoracearum Apply Ampelomyces , azoxystrobin, kresoxim methyl, or triadimefon to protect leaves. Rhizoctonia Crown Rot Stems at the soil level have a brown lesion. Plants wilt and die. Rhizoctonia solani Plant in pasteurized media. Thielaviopsis Root Rot Plants yellow, wilt, and die.
Roots are dark brown to black as thick-walled dark spores form in the cells .
Thielaviopsis basicola Plant in pasteurized media. Viruses Leaves may be mottled, have yellow spotting, dead flecks, line or ring spot patterns. Plants may be distorted or have flower color breaking. Impatiens necrotic spot, tobacco rattle, gerbera mosaic, and cucumber mosaic viruses. Maintain good insect and mite control.