Tomatoes are a truly versatile and delightful vegetable that any gardener should strive to grow in their garden. Besides growing plants, you must take over several problems associated with yellow leaves having brown spots or even both.
The two most common causes of yellow leaves with brown spots on tomatoes are fungal and nutrient deficiencies. Environmental factors such as excessive heat, moisture, lack of air circulation, and pests contribute to these issues as well.
If an issue arises with a single plant, the cure will be distinct from one associated with multiple plants whether it is from organism or physiological.
In this article, we will provide a comprehensive overview of the topic at hand as well as relevant information on its causes and possible preventative measures.
Why Do Tomatoes With Yellow Leaves Have Brown Spots?
If you have noticed yellow leaves with brown spots on tomatoes, it is time to find out what is causing this problem. In most cases, the cause of these issues is-
Fungal infections are caused by different fungi which can attack plants through their leaves, stems, and even roots. These fungi cause disease in the form of brown spots on the tomato leaves. Some of the diseases accused of fungal causes are-
|Septoria leaf spots
|Bottom of the leaf spotting and yellowing
|The leaf area emerged with dark-brown to black areas with the quickly enlarged water-soaked lesion
|Turn grey to the dark-brown margin of the underside of the older leaves.
|Temperatures exceeding ( 75° – 84°F )and relative humidity over 95%.
|Cool (60°F to 70°F) and damp, rusty conditions
|Between 68 °F – 77 °F .
|Possible Solutions/ Fungicide
|Daconil® fungicides @ 15 gram per 1 gallon/ 7-10 days interval
|Mancozeb @ 4-16 gram per L (as per severity) / 1 week interval
|Daconil @ 4 gram per L / 1 week interval
Though these are the most common fungal diseases of tomatoes, there are many others. To identify the exact cause and take preventive measures against it, you need to contact a professional agricultural expert or conduct lab tests.
Here is my other example of a fungal disease with symptomatic occurrence-
|Fungus/ Causal Organism
|By yellowing and wilting of the lower leaves of the tomato plant, followed by the death of the plant.
|Yellowing and wilting of the lower leaves of the tomato plant.
|Variety of fungi, including Pythium, Fusarium, and Rhizoctonia
|Stunted growth and death of the tomato plant
|Small, circular, black lesions on the fruit of the tomato plant
|Grey, fluffy mold on the fruit, leaves, and stems of the tomato plant
|A white, powdery coating on the leaves and stems of the tomato plant
|Black, sunken lesions on the fruit of the tomato plant
|Yellowing and wilting of the leaves of the tomato plant.
|Small, circular, gray, or brown spots on the leaves of the tomato plant
|Rhizoctonia Root Rot
|Stunted growth and death of the tomato plant.
In a different study, It was observed that Daconil (Chlorothalonil) can be used to control over 65 types of fungus disease associated with the tomato crop. (Its solubility in water is 10 mg/100 mL)
Daconil should be applied every 7-14 days to keep the disease in check. It is also important to rotate fungicides as resistance can build up. Other fungicides that can be used for controlling tomato fungal diseases include mancozeb, captain, and copper hydroxide products.
It is also important to practice proper crop rotation and use disease-resistant cultivars wherever possible. Additionally, good farm management practices should be followed to prevent the spread of fungal diseases in tomato crops.
Nutrient deficiencies can also be identified by yellow leaves with brown spots on tomatoes. These nutrient deficiencies may include zinc, magnesium, nitrogen, iron, or potassium.
Here are several nutrients that can cause yellowing leaves and brown spots on tomato plants. Some of the most common nutrients that can cause these symptoms to include:
- Nitrogen: Nitrogen is an essential nutrient for tomato plants, but too much of it can cause the leaves to turn yellow. This is because excess nitrogen can interfere with the plant’s ability to absorb other important nutrients, such as iron and zinc.
- Iron: Iron is necessary for the production of chlorophyll, which gives plants its green color. But less iron or lack of iron can cause the leaves to turn yellow with brown spots.
- Zinc: Zinc is necessary for the proper development of the plant’s root system and for the production of enzymes that help with the metabolism of carbohydrates and proteins.
- Manganese: Manganese is a trace element that is important for the proper development of the tomato plant. A deficiency of manganese can cause the leaves to turn yellow and the stems to become stunted. Manganese is also important for the synthesis of chlorophyll and the production of plant hormones.
- Potassium: Potassium is an essential nutrient for tomato plants, and a deficiency of potassium can cause the leaves to turn yellow and the fruit to become small and poorly formed. Potassium is important for the proper functioning of the plant’s cells and for the synthesis of proteins and enzymes.
- Phosphorus: A deficiency of phosphorus can cause the leaves to turn yellow and may also lead to stunted growth and reduced yields. Besides, phosphorus is important for the synthesis of proteins, DNA, and RNA.
Environmental factors such as excessive heat, moisture, lack of air circulation, and pests can also lead to yellow leaves with brown spots on tomatoes. These conditions are particularly common in enclosed greenhouses or when the temperature is too high and there is not enough ventilation.
But if you could take the necessary steps to improve the environment for your tomato plants, such as providing adequate sunshine and air circulation, controlling pests and diseases, and maintaining the right soil moisture level, then you should be able to reduce or eliminate any yellowing of leaves with brown spots on tomatoes.
Also, make sure that your garden soil is not compact because this can reduce the availability of nutrients and air to the plant roots, which could lead to nutrient deficiencies, root malgrowth, and yellow leaves with brown spots on tomatoes.
Finally, using a fertilizer formulated specifically for tomatoes can help ensure that they have all the necessary nutrients to maintain healthy growth. Soil tests should also be conducted periodically to identify any nutrient deficiencies or soil pH imbalances that may be causing yellow leaves with brown spots on tomatoes.
Overall, yellow leaves with brown spots on tomatoes can occur for a variety of reasons, but it is important to investigate what the cause could be to address the issue effectively. With proper care and attention, you should be able to restore your tomato
Recovering Wrap Up
To recover yellow leaves with brown spots on tomatoes, it is important to identify the cause of the problem. I have discussed all the possible causes with symptomatic solutions.
Once you have identified the underlying cause, you can take the necessary steps to correct it.
I am a graduate of Bangladesh Agricultural University, where I delved into various agricultural disciplines, equipping me with a profound understanding of agriculture. Beyond academics, I have hands-on experience in gardening and crop cultivation. My passion is to embrace sustainable farming and horticulture. With a BSc in Agriculture, I am dedicated to promoting environmentally conscious and efficient agrarian practices.
Bachelor of Science (BSc) in Agriculture (Hons.)
Master of Science. (Sustainable Agriculture & Food Security ) (MS)
Bangladesh Agricultural University