Fungicide Resistance AWake Up Call For Rice Producers

STUTTGART, ARK.
   The discovery of fungicide resistant diseases in Louisiana rice last year should be a wake up call for Arkansas rice producers this year, said Yeshi Wamishe, extension plant pathologist for the University of Arkansas System Division of Agriculture.
   “Troubling news came in the summer of 2011 from Louisiana, where failure of the fungicide to control sheath blight was confirmed in a few fields,” she said.
   Those reports immediately set Arkansas researchers in motion to see if resistance to strobilurin fungicides was present here.
   “We collected samples from fields in Arkansas with known long-time use of fungicides and sent them in for testing,” Wamishe said. “Fortunately, all our samples were negative for resistance to the strobilurin fungicides.”
   However, she warns: “if we continue down our current usage path, it’s likely that resistance will develop here.”
   Other diseases at risk of developing fungicide resistance are kernel smut and rice blast.
   The strobilurins currently used in rice, including Quadris = azoxystrobin; Gem = trifloxystrobin; Stratego = trifloxystrobin + propiconazole; Quilt and Quilt Xcel = azoxystrobin + propiconazole, “may someday fail together and there is not much in the commercial pipeline to replace these products, if anything,” Wamishe said.
   To avoid resistance, she recommends Arkansas rice growers:
   • Scout for sheath blight before spraying and not make automatic applications
   • Use recommended rates and timings
   • Spray at early to mid-boot for the smuts
   • Use 6 fluid ounces of Tilt equivalent for smuts, not lower rates
   • For blast, plant problem fields with blast-resistant varieties
   • Keep the flood deep in blast-prone fields
   • Use the correct timing and rates for blast, do not wait too late to spray
   • Contact us to inspect fields where the fungicides have failed  Δ 

This shot clearly shows sheath blight lesion. University of Arkansas Division of Agriculture photo