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Deal With Septoria Leaf Spot On Tomatoes Leaves

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Tomatoes suffer from all sorts of diseases. Septoria Leaf Spot on tomatoes is no exception. Caused by a fungus called Septoria lycopersici. It is very destructive to the foliage of your tomato plants. It is caused by damp humid conditions and is more persistent when this sort of weather persists for long periods of time.

What To Look For? How To Deal With It?

Occurring on lower leaves initially Septoria Leaf Spot takes hold after the first fruits are set. Spots can be very small around 1.5mm to 6.5mm they are usually circular in a pattern but this can vary and they can be elongated.

Septoria Leaf Spot
Tomato 1
Tomato 1

Colouration is dark brown rings surrounding beige or grey centres With multiple spots per leaf the disease spreads from the oldest growth to the newest. This causes the leaves to turn pale yellow in colour eventually moving on to brown then dying off altogether.

This can cause a lack of photosynthesis as the plant will struggle to invert the sugars required. Septoria Leaf Spot rarely affects the fruit of the plant

Tomatoes suffer from many diseases like Septoria Leaf Spot. Pale Yellow leaves with brown or grey circular or elongated patches

Septoria Leaf Spot Life Cycle!

Overwintering on infected material from the nightshade family. Such as tomatoes and potatoes. This fungus will persist not only on living vegetation but on tools and equipment such as secateurs, canes, and cages.

Septoria Leaf Spot loves high humidity so ventilation is very important to prevent it. It requires temperatures of 60-80 degrees Fahrenheit or 15 to 26 celsius. Wet leaves can also speed up the spread of Septoria Leaf Spot.

12 Tomato TIPS – Become A BETTER Gardener


Watering carefully is a must to prevent this disease keep the foliage dry at all times. How To Control Septoria Leaf Spot? Water management is a must control. You should not overhead water your tomato plants. Keeping the foliage dry is the utmost priority. Instead, use Drip Irrigation. Drip Tape. Soaker Hose all of which will provide adequate water to your plants while keeping the plant itself dry.


Lower leaves of tomato plants will be the first to be affected by Septoria Leaf Spot, These should be removed immediately upon seeing this disease. If removed early enough you can prevent its spread to the rest of the plant, and neighbouring plants. These leaves should not be composted, Neither should the plant at the end of the growing season. Instead, they should be burned in a garden incinerator


Air circulation is king. Ensuring adequate air movement will help reduce the chances of catching Septoria Leaf Spot. Allow bigger spacings between plants when first planting out, Plant in a staggered pattern so the foliage is not able to be compressed to each other. This will greatly help in preventing the spread. The biggest cause of Septoria Leaf Spot is hot humid conditions when water gets the leaves wet.


You can also help with this by mulching around the plants. This will help cut down evaporation reducing the humidity. Will prevent soil-borne spores from splashing up on leaves during watering. Weeding also helps with controlling Septoria Leaf Spot, Especially weeds such as Horsenettle part of the nightshade family which is a frequent host of Septoria Leaf Spot.

If you have suffered from Septoria Leaf spot then consider growing your crops in other parts fo the garden or greenhouse. At the very least you could replace the soil to reduce the infestation. It can typically take over two years before you can grow tomatoes in the same soil again.


And as a last resort, fungicidal sprays can be used to control the disease. These will not kill the disease but will prevent new leaves from becoming infected. Apply weekly to ensure adequate protection Use something similar to Solabiol 100% organic copper fungicide and bactericide Or Neem Oil. Follow the instructions and be mindful of harvest times if you have to use this route.

Pale Yellow leaves of Septoria Leaf Spot
Septoria leaf spot on tomato leaves


So that’s Septoria Leaf spot and how to deal with it. I hope this article has been of use to you. If it was, consider checking out more of my articles from the blog pages, or even subscribing tot he blog in the right-hand sidebar