The blind-seed disease fungus (Gloeotinia temulenta) increased in prevalence rapidly in western Oregon from 1941 to 1944 until nearly 90% of perennial ryegrass (Lolium perenne) crops were infected. A control program started in September, 1944 and based mainly on reducing inoculum by plowing under severely diseased plantings reduced the incidence of seriously infected crops. Fields with no disease increased from 13% in 1944 to 27% in 1945 and to 52% in 1946. This progress in control was lost during 1947 and 1948, because many diseased fields were not plowed after the 1946 and 1947 harvests. The disease increased to former levels and severely damaged the 1948 crops. Burning of fields was recommended after the 1948 harvest. Since then, annual burning of nearly all fields has effectively destroyed inoculum and provided excellent control of the disease. Seed with less than 85% germination was held to less than 1% of the crop for 6 consecutive years (1950-55). Partial failure of the control program permitted an increase in disease incidence during 1956 and 1957; consequently, crop damage increased during 1957. The breakdown in control was due to (1) reduced value of field burning caused by uneven distribution of crop residues from use of straw choppers on combines and (2) excessive recontamination of fields by light-weight infected seed blown out during threshing. Correction of these errors restored effective control of G. temulenta during 1958-61. The highly successful control of blind-seed disease obtained entirely by cultural methods at a very low cost has permitted continuation of economic production of perennial ryegrass seed.