What are these brown pellets found on the base of a tomato plant?

Brown pellets are sclerotia from the soil-borne fungus Athelia rolsii, commonly called Southern blight.
Rob Last, ©2024, Clemson Extension
These brown pellets are sclerotia from the soil-borne fungus Athelia rolsii, commonly called Southern blight. The photograph was taken from a tomato plant displaying wilting with a good fruit loading. Sclerotia are survival structures that allow the fungus to survive in the soil for many years. White mycelial growth may also be present at the base of the stem when environmental conditions are ideal. More information and management options for Southern blight can be found here.