Controlling rhizoctonia seedling disease of cotton in Southern California

Best treatments for control of Rhizoctonia pre- and post-emergence damping-off of cotton seedlings were: (1) Terra-Coat L-21 (PCNB-Terrazole) seed treatment plus PCNB-Terrazole in-furrow granular; and (2) Demosan seed treatment. Demosan seed treatment plus Demosan in furrow granular was no better than Demosan seed treatment alone. Terra-Coat L-21 seed treatment plus PCNB-Terrazole in-furrow granular gave excellent control in one trial without the basic mercury treatment.

Intermediate in effectiveness were: (1) Vitavax seed treatment; (2) Terra-Coat L-21 seed treatment; and (3) PCNB in-furrow granular. However, Vitavax seed treatment was one of the best materials tested in two trials at the UC Meloland Field Station in Imperial Valley. Bay 78175 in-furrow spray effectively cantrolled Rhizoctonia damping-off in the only trial where it was applied.