Black Spots on Tomato Leaves: Treating Septoria Leaf Spot

Septoria leaf spot is a quite common tomato illness. It’s attributable to a fungus (Septoria lycopersici) and may have an effect on tomatoes and different vegetation within the Solanaceae household, particularly potatoes and eggplant, nearly anyplace on the earth.

Though Septoria leaf spot will not be essentially deadly on your tomato vegetation, it spreads quickly and may shortly defoliate and weaken them, rendering them unable to bear fruit to maturity. Septoria leaf spot causes black spots on tomato leaves with small fruiting our bodies (raised bumps) within the heart, leading to yellow leaves that finally flip brown and die.

Be taught what Septoria leaf spot is and the best way to determine, deal with, and forestall it when rising tomatoes.

What Is Septoria Leaf Spot?

Septoria leaf spot is a fungal illness that causes black or brown spots on the older, decrease leaves of the plant however not on the fruit. The illness can shortly unfold upward on the plant, affecting new development, producing much less wholesome or flavorful fruit, and general, making the plant vulnerable to solar scorch. The illness turns into extra prevalent when the backyard has heat, humid circumstances.

Signs of Septoria leaf spot are sometimes confused with early blight. Septoria leaf spot seems as lesions on older leaves dotted with tiny brown-black dots. Early blight exhibits as bigger, barely sunken lesions embedded with concentric rings.

Figuring out Septoria Leaf Spot on Tomato Crops 

Septoria leaf spots begin considerably round and first seem on the undersides of older leaves on the backside of the plant. They’re small, 1/16 to 1/8 inches (1.6 to three.2 millimeters) in diameter, with a darkish brown margin and lighter grey or tan facilities. A yellow halo might encompass the spot.

Because the illness develops, the spots will get bigger and should merge. For those who view them via a magnifying lens, you may even see the fungus’s fruiting our bodies, which seem like darkish brown pimples. This is likely one of the signs that distinguishes Septoria leaf spot from different leaf-spotting illnesses.​

Though the signs often happen within the older, decrease leaves, the illness can develop at any stage within the tomato plant’s life. It could additionally seem on the stems, blossoms, and calyxes (starfish-shaped inexperienced leaves on prime of every tomato fruit). The excellent news is that it not often impacts the fruits.

If untreated, Septoria leaf spot causes the leaves to show yellow and finally dry out and fall off. This weakens the plant, sends it into decline, and causes solar scalding of the unprotected, uncovered tomatoes. With out leaves, the plant won’t proceed producing and maturing tomatoes.

How Septoria Leaf Spot Spreads

Fungus spores are superb at hiding out and ready for perfect circumstances. They will journey nice distances in hopes of discovering these circumstances. The Septoria lycopersici fungus lives on the fallen tomato plant particles and weeds on and within the soil, which may overwinter.

Septoria leaf spot is unfold to vegetation by water splashing up on them from the soil, in addition to bugs, individuals, and tools that are available in contact with the fungus. Heat (60 to 80 levels Fahrenheit), humid circumstances are probably the most favorable for Septoria leaf spot to develop, and that is when you ought to be most watchful. If caught early, it may be managed. However observe that Septoria leaf spot spreads quickly.

The best way to Deal with Septoria Leaf Spot

There are just a few choices for treating Septoria leaf spot when it seems; these embody:

Eradicating Contaminated Leaves

Take away contaminated leaves instantly. Wash your fingers and slicing instruments completely earlier than you prune tomato vegetation that aren’t contaminated.

Contemplate Natural Fungicide Choices 

Fungicides containing both copper or potassium bicarbonate will assist stop the spreading of the illness. Start spraying as quickly as the primary signs seem and observe the label instructions for continued administration.

Contemplate Chemical Fungicides

Whereas chemical choices aren’t perfect, they often is the solely possibility for controlling superior infections. One of many least poisonous and simplest is chlorothalonil (bought as Fungonil and Daconil).

The best way to Stop Septoria Leaf Spot on Tomatoes

You in all probability will not have the ability to keep away from Septoria leaf spot altogether. Given the best circumstances, it’s prevalent and can attempt to take maintain in your backyard. Nonetheless, there are some precautions you may take to decrease the probability that Septoria leaf spot will happen.

Use Illness-Free Seed

There is no proof that this fungus is carried by seeds, however err on the secure aspect and do not save seeds from contaminated vegetation. Totally processing the tomato seeds you’re saving will even assist rid the seeds of lingering illnesses.

Begin With a Clear Backyard

Eliminate all affected vegetation. The fungus can overwinter on the particles of diseased vegetation, so it is vital to eliminate all of the affected vegetation far-off from the backyard and the compost pile. Take into account that it could have unfold to your potatoes and eggplants, too. Cage tomatoes (disinfect cages yearly) to stop leaves from touching the bottom or different vegetation.

Keep away from Overhead Watering

Water aids the unfold of Septoria leaf spot. Water the plant on the base solely to maintain it off the leaves as a lot as doable. After all, protecting the rain off your vegetation is unimaginable, however each little bit helps.

Present Room For Air Circulation

Go away correct spacing between your tomato vegetation so there’s good airflow. Stake them so they aren’t touching the bottom and never all bunched collectively. Good air circulation is important throughout damp and wet durations.

Mulch Under the Crops

A layer of mulch will assist stop spores on the bottom from splashing up onto the decrease leaves.

Use Baking Soda and Vegetable Oil

Spray a pure fungicide answer on wholesome tomatoes to stop pests and fungal illnesses. Combine 1 heaping tablespoon of baking soda, 1 teaspoon of vegetable oil, just a few drops of dish cleaning soap, and one gallon of water in a sprig bottle. Reapply weekly, within the morning or night, to assist your vegetation keep wholesome.

Plant Subsequent Yr’s Tomatoes in a Completely different Part

In small gardens, rotating crops will not be all the time sensible, so good cleanup and sanitation grow to be much more vital. But when doable, plant your subsequent crop in a special space of your backyard.