Efficacy of Flutriafol Fungicide for Control of Cotton Root Rot in Arizona in 2012 and 2013 Field Trials

Tuesday, January 7, 2014
Mardi Gras Ballroom Salons E, F, G & H (New Orleans Marriott)
Wednesday, January 8, 2014
Mardi Gras Ballroom Salons E, F, G & H (New Orleans Marriott)
Randall Norton , The University of Arizona
Mary W Olsen , The University of Arizona
Ayman Mostafa , The University of Arizona
Field experiments were established in Arizona during 2012 and 2013 to evaluate the efficacy of flutriafol fungicide (Topguard) on the control of cotton root rot caused by the soil-borne fungus Phymatotrichopsis omnivora.  Trials were established in grower cooperator fields in Marana and Safford, AZ in both 2012 and 2013. 

 In 2012, flutriafol was applied at 16 and 32 fl oz/acre as a 5-inch T-band spray directly over the seed trench at planting at both sites.  The experimental design was a paired t-test. In 2013, flutriafol was applied at 32 fl oz/acre using different application techniques: the T-band (at both sites); an at-planting in-furrow treatment utilizing a seed firming device (Schaffert Mfg.), and pre-plant injection into the seed bed (Safford only).  The experimental design was a completely randomized block at each site with 6 replications.   Treatments were evaluated by counting the number of linear feet of diseased plants in each plot and from yields of seed cotton. 

 In 2012, disease incidence was reduced significantly in Safford with both the 16 and 32 oz/acre rates when compared to the non-treated control, but results were not significant at Marana.  No significant differences in disease control were observed between the 16 and 32 oz rates.  Yield differences in 2012 were non-significant at either location.  Results in 2013 at Safford showed an overall 70% reduction in disease incidence between the non-treated control and the three application techniques, and all three techniques were significantly different from the non-treated control. There were no significant differences in disease control among application techniques.  At Marana, disease was reduced significantly with a 69% reduction in disease between the treated and non-treated control.  Yield data has yet to be collected for 2013.