Plants affected with pith necrosis do not exhibit the marginal necrosis of leaflets nor the bird's-eye spotting of the fruit characteristic of bacterial canker. Plants may die if the lower stem is affected, however, the disease usually does not progress, and plants will outgrow the condition. Hollowed, chambered pith of pith necrosis. High nitrogen fertilization, cool night temperatures, high relative humidity, and plastic mulches all increase incidence and severity of pith necrosis. The disease frequently occurs when the first fruit set is close to mature green.
Control requires avoiding excessive nitrogen rates.
Tomato spotted wilt is caused by a virus that is usually spread by thrips. Tomato plants infected with spotted wilt become stunted and often die. Initially, leaves in the terminal part of the plant stop growing, become distorted, and turn pale green. Necrotic spots, or ring spots, are frequently present on infected leaves and stems often have purplish-brown streaks. Bronzed, purpled leaves of tomato spotted wilt.