The Q&A Archives: Tomato Disease

Question: I have 21 tomatoe plants and they all have the same disease. It looks like rust or light brown spots on my leaves it is making my plants not produce good tomatoes. Any suggestions?

Answer: Tomato plants can fall victim to many fungal diseases and light brown or rusty spots on leaves are symptomatic of nearly all of them. Bacterial spot thrives in damp, rainy conditions and affects both the fruit and the leaves. Early blight produces brown spots with outer yellow circles. Fusarium wilt generally causes leaves to yellow and occurs when temperatures are high. Late blight hits older leaves first and rapidly progresses up the entire plant. Septoria leaf spot (or blight) begins with water-soaked spots on leaves which eventually turn gray in the middle. None of these diseases is easily controlled. You can try picking off the infected leaves and fruits, but doing so could result in sunscald of the remaining fruit. It's difficult to recommend any other control measure until we know for sure which disease your tomatoes have developed. For positive identification and treatment recommendations you can contact the University of Puerto Rico, College of Agriculture at (787) 833-2665.

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