Rice - Sheath Blight Fungicide Treatment Thresholds

Treatment Threshold at 7-14 days past 1/2” internode elongation3
Rice Variety	Sheath Blight Reaction	Percent Positive Stops	Percent Infected Tillers
AB6565	VS	35	10-May
Clearfield (R) CL-121	VS	35	10-May
Clearfield (R) CL-141	VS	35	10-May
Clearfield CL-161	VS	35	10-May
Cocodrie	VS	35	10-May
Cypress	VS	35	10-May
Lemont	VS	35	10-May
Madison	VS	35	10-May
CL161	VS	35	10-May
AB 647	MS	50	15-Oct
AB1542	MS	50	15-Oct
AB6465	MS	50	15-Oct
Ahrent	MS	50	15-Oct
Alan	MS	50	15-Oct
Bengal	MS2	50	15-Oct
Drew	MS	50	15-Oct
Earl	MS1	50	15-Oct
Francis	MS	50	15-Oct
Jefferson	MS	50	15-Oct
Kaybonnet	MS	50	15-Oct
Koshihikari	MS1	50	15-Oct
LaGrue	MS	50	15-Oct
Newbonnet	MS	50	15-Oct
Priscilla	MS	50	15-Oct
Saber	MS	50	15-Oct
Wells	MS	50	15-Oct
XL-6 Hybrid Rise	MS2	See footnote3	See footnote3
XL-7 Hybrid Rice	MS	50	15-Oct
XL-8 Hybrid Rice	MS	50	15-Oct

1These varieties rarely benefit from sheath blight fungicide applications.
2Under low nitrogen management, XL-6 should not need a fungicide application.
3Thresholds are based on adequate scouting. Each field should be scouting in a zigzag pattern avoiding the edges
and ends of the field, stopping every 50 steps to inspect a 3 ft. long section of rice. If any symptoms are observed
in the section, this is a positive stop. At least 50 stops per field should be made or 1 per acre in large fields. If
sheath blight is concentrated in certain parts of the field, treat only the infected region if it exceeds the threshold.
Field history should also be used to determine the need for a fungicide application.
--Rick Cartwright and Fleet Lee, University of Arkansas