Effect of Calcium applied Alone or with Ronilan Fungicide at two growth stages for control of white Mold on Canola Langdon, ND 2002. 

S. Halley, Langdon Research Extension Center-North Dakota State University, Box 310 Hwy 5 E Langdon, North Dakota 58249

*Corresponding author PH: (701) 256-2582, E-mail: shalley@ndsuext.nodak.edu   

Environmental conditions permitted development of only trace levels of white mold (Sclerotinia sclerotiorum).  No significant responses to yield, test weight, stand, plant height, and % oil, were found between fungicide treatments or application timing.

An experiment, randomized complete block design arranged as a 3 x 5 factorial with four replicates, was initiated at the Langdon Research Extension Center to determine effects of the calcium supplements, calcium sulfate or calcium chelate, applied alone or in combination with fungicide Ronilan (vinclozolin) for the control of white mold in canola at rosette, first flower, or rosette + first flower growth stage. Sclerotia harvested from sunflower and sclerotia prepared in vitro were broadcast, packed with a grain drill, and covered with soil prior to planting, 20 May. The cultivar �InVigor 2733� received rosette growth stage calcium applications on 24 June and/or first flower applications on 29 June. To improve the potential infection, ascospores were broadcast by CO₂ backpack spray application 5 July at growth stage 30-40% bloom. The calcium chelate (12% calcium and 4% chelate) and calcium sulfate (29.2 % calcium and 17% sulfate) were commercial products supplied by NWC, Inc. The calcium chelate was applied at 3 qt/acre, calcium sulfate at 3.5 lb/acre, and Ronilan at 12 oz/acre. Supplement water was applied on several occasions through an overhead sprinkler system to increase potential for white mold infection. The CO₂ backpack spray applications were applied at 40 psi in 18 gpa water with XR8002 nozzles.  Data was analyzed with the general linear model (GLM) in SAS. Least significant differences (LSD) were used to compare means at the 5% probability level.

June average temperature was 2 degrees above normal with precipitation at 6.37 inches, 3.2 inches above normal. The average July temperature was over two degrees above normal and precipitation nearly two inches below 30 year normal, 2.9 inches. The greatest rainfall event of the month was 0.36 inches on 5 July. July weather was not conducive to the development of disease.