BIOLOGICAL-CONTROL OF SOUTHERN BLIGHT DISEASE OF TOMATO CAUSED BY SCLEROTIUM-ROLFSII WITH SIMPLIFIED MYCELIAL FORMULATIONS OF TRICHODERMA-KONINGII

Two simple formulations of an antagonistic strain of Trichoderma koningii were employed against southern blight disease caused by Sclerotium rolfsii in seedling, potted outdoor and field-grown tomatoes (cvs. Ife No. 1 and Ibadan Local). Corn cob germling inoculum and mycelium powder of T. koningii significantly controlled (P less-than-or-equal-to 0.05) symptoms of damping off, blight and wilting in both tomato cultivars. The populations of the antagonist increased from an initial 1 x 10(4) to about 1 x 10(6) colony-forming units per g of soil in the protected plants. Moreover, sclerotial counts decreased significantly (P less-than-or-equal-to 0.05) in these soils and those sclerotia found had been parasitized by T. koningii. Trichoderma-protected plants were more vigorous than those in the other treatment categories. The significance of these results is discussed in relation to the use of Trichoderma in appropriately simplified formulations.