The only disease seriously affecting crimson clover is the clover stem-rot, root-rot, or wilt, a disease resembling the stem-rot, or wilt, of lettuce and other plants. This disease is prevalent in nearly all the crimson-clover States and sometimes does considerable damage. The stem-rot affects the clover at all seasons, but is more noticeable in the spring, when it sometimes causes large spots of clover suddenly to wilt and fall. Occasionally an entire field is affected, but the disease is most prevalent in low, rich spots. Examination of the plants discloses a rotting off or decay of the stems close to the ground, followed immediately by the appearance on the stems of small black lumps, or sclerotia, about the size of clover seed. These sclerotia are a means of spreading the disease and are often harvested in the hay or in the seed crop. The only known remedy for the stem-rot is to cease growing clover or alfalfa on an infested field for three or four years, substituting cowpeas or soy beans. Seed from fields known to be infested should, of course, be avoided.

No insects are known to affect crimson clover seriously, nor are weeds of great importance in clover planted on clean fields. When planted in cultivated crops or in poorly prepared ground crimson clover is often seriously damaged by a rank growth of chickweed, knawel (moss weed), winter cress, and other winter-growing annuals.

WASHINGTON : GOVERNMENT PRINTING OFFICE : 1920