406 OHIO EXPERIMENT STATION: BULLETIN 214 © 
examination shows that the stem tissues are somewhat brown and that the 
brown and dead rootlets are occupied by the fungus which is referred to a 
species of Fusarium. This disease is at present under investigation and should 
be controlled, if at all, by the thorough soil treatments recommended under 
lettuce rosette. It will be no use to disinfect the houses and then grow plants 
in diseased soil. 
Fig. 57. This shows root portions of seedling lettuce plants with dark spots, lesions caused by 
attacks of the rosette fungus, AAzzoctonia, With the younger plants these attacks cause large mortality 
and in very small seedlings the stem of plantlet may early collapse after the manner shown in rotting 
specimens, (From Circular No. 57). 
Tip-burn. Tip-burn of lettuce leaves is often brought to notice. Usually 
it is associated with unsatisfactory watering in the greenhouse. or with extreme 
changes to summer weather. The remedy consists in the methods of watering 
employed. 
