47th TWC, Tob. Work. Conf., 2016, abstr. 64

Evaluation of fungicides for the control of blank shank and yield response on tobacco

Clemson University, Pee Dee Research & Education Center, Florence SC USA

Presidio, Ridomil Gold and Orondis (Oxathiapiprolin) fungicides were tested on-farm for the past two growing seasons (2014, 2015) in Sumter County, SC, for the control of Phytophthora parasitica var nicotiana on tobacco. A randomized complete block design was used to test the selected treatments. Treatments were replicated four times each season. Tobacco seedlings were removed from a greenhouse float system and transplanted into single row plots 40 feet long on 4-foot row spacing. Fertilizer (6-6-18 N, P, K analysis) was applied at transplanting and an additional fertilizer application of 15.5-0-0 N, P, K analysis was made at first cultivation. Fertility rates followed state recommendations. Selected treatments received Presidio, Ridomil Gold and Orondis fungicides in the transplant water applied in 100 gal/A. Transplant water plus fungicide treatments were hand applied to each plant receiving the treatment. The untreated control received only water. During 2014, soil applied fungicide treatments were made at 1st cultivation and at layby. Soil applied fungicides were sprayed over the row as a directed spray to each side of the planting bed and incorporated immediately after application with a field cultivator. During 2015, a single soil applied fungicide treatment was made at layby. In 2014 Presidio, and Orondis significantly increased yield and reduced the percent disease and disease index (P = 0.05) when applied across all application rates and application timings. Disease control was influenced by the time of application and application rate. In 2015 all Presidio + Ridomil Gold and Orondis + Ridomil Gold applications increased yields and reduced the disease index (P = 0.05) over a non-treated control. (Reprinted with permission)