Details for Eliminating Fungal Spores and Avoiding Blight in Tomato Fields

If this was an intensive commercial horticulture situation you might consider soil fumigation just prior to planting. This could potentially reduce disease inoculum. Otherwise rotate to a different crop. If tomatoes again then a good preventative fungicide program for the designated disease should provide good control.

The cause of the blight is Alternaria solani. Also want to monitor your irrigation and rainfall as saturated soils and humid conditions can enhance to fungus. The important thing is understanding what are the prime things the disease needs. Water, humidity, very little air flow in the canopy at prime for most diseases in crops. There are so many things that need to be looked at when trying to control a fungus such as this. You might think about getting on a fungicide program alternating modes of action. My 10 cents.

The most important thing to do in the situation is to remove all infected plants at the time of recognition. To control in the future you will need to rotate your spot for your tomatoes. I never put tomatoes in the same spot every year. Always rotate through the garden. Rotating to another crop can help decrease the fungal load.