No. Leaves only. There are stem borers but usually in roses. Never seen in tomatoes. When u separate the stem does a gummy sinuous type liquid trail away from both ends? Dont cut but break apart and slowly separate If so type of virus and off top of my head don't remember the name. Message back if correct and will look up. Verticillium or fusarium wilt likely but that is bacterial or leaves only first the invades plant. Virus plant specific