Among the compounds registered for use in Connecticut are benomyl and thiophanate-methyl. Consult the label for dosage rates and safety precautions. Rhizoctonia solani . This general droopiness or flaccid appearance is often accompanied by browning and rotting of the roots and the crown. Yellowing and death of the outer leaves follows, until finally the entire plant is dead.
Control can be difficult once plants are infected so prevention is important.
It is helpful to avoid overwatering, especially in heavy soils, and to avoid watering directly into the crown area of the plant. Highly symptomatic plants can be rogued and removed since recovery is unlikely. Symptoms include small blister-like spots that appear on both tuberous and fibrous begonias. The spots are translucent at first and as they age, the centers dry to a tan color. The margins of the spots usually remain translucent or water-soaked.