According to Professor of Plant Pathology and Extension Specialist Mohammad Babadoost, the EPA has approved the use of cyazofamid (Ranman 400SC) and mandipropamid (Revus 2.08SC) in Illinois for the period from April 17 through October 15, 2012. Ranman (EPA Reg. No. 71512-3), a fungicide from the FMC Corp., and Revus (EPA Reg. No. 100-1254), manufactured by Syngenta Crop Protection, are protectant-systemic compounds.
In Illinois, the growing season for basil is from the beginning of May through the middle of October (approximately 23 weeks). Downy mildew of basil, caused by the oomycete pathogen Peronospora belbahrii, was first detected in Illinois in 2009 and now occurs in the state every year.
“Downy mildew develops very rapidly and can cause 100% crop losses in a short period of time,” Babadoost said. “Control of downy mildew of basil requires fungicide protection of plants from the beginning of June through September – approximately 17 weeks.”
Babadoost suggests alternating applications of Ranman 400SC, Revus 2.08SC, and azoxystrobin (Quadris 2.08SC) at weekly intervals (up to 17 spray applications).
Ranman, with a Fungicide Resistance Action Committee (FRAC) Code of 21, can be applied up to six times in the growing season. The maximum amount of product permitted is 16.5 fluid ounces per acre for the season, with a maximum of 2.75 fluid ounces per acre permitted per application.
Revus, with FRAC Code of 40, can be applied up to four times. The maximum amount of product permitted is 32 fluid ounces per acre for the season with a maximum of 8 fluid ounces per acre permitted per application.
Quadris, with the FRAC Code of 11, can be applied up to six times. The maximum amount of product permitted is 92.3 fluid ounces per acre for the season with a maximum of 15.4 fluid ounces per acre permitted per application.