THE GROWTH OF BOTRYTIS CINEREA PERS., FUSARIUM CAERULEUM (LIB.) SACC., AND PHOMA FOVEATA FOISTER IN THE PRESEXCE OF TETRACHLORONITROBENZENE ISOMERS

The linear growth of Botrytis cinerea, Fusarium caeruleum and Phoma foveata in culture was reduced in the presence of vapour from any of the three isomers of tetrachloronitrobenzene. The isomers were fungistatic hut not fungicidal. Differences in activity were observed amongst the isomers. The 2: 3: 4: 6 isomer was the most active against all three test fungi. 2: 3: 5: 6-TCNB (tecnazene) was more active than 2: 3: 4: 5-TCNB against Botrytis cinerea, hut less active against Fusarium caeruleum and Phoma foveata. Two strains of Fusarium caeruleum resistant to the 2: 3: 5: 6 isomer were not resistant to the other two isomers, although they were more resistant than their 2: 3: 5: 6- TCNB sensitive parent strains. Sporulation and sclerotial production by Botrytis cinerea were completely suppressed by 2: 3: 5: 6-TCNB and 2: 3: 4: 6-TCNB but not by the 2: 3: 4: 5: isomer.