Pith necrosis
Pith necrosis (Pseudomonas corrugata) :
It causes yellowing and wilting of leaves, blacking and enlarging of petioles and nodes, and progressing to top of plant; yellowing and wilt of entire plant
Control: It can be prevented by avoiding the use of excessive amounts of nitrogen in tomato, especially early in the season when nights are still cool. Using plant activators such as acibenzolar-S-methyl (Actigard) have resulted in 55% disease reductions, but applications must be started before symptoms appear.