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13 Diseases your tomato plants are suffering from

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Tomatoes. If you grow your own fruit and vegetables, then no doubt you have tried growing them. With the right effort, most people can get an ok crop of vine-ripened tomatoes in summer. But for some, they are plagued with all sorts of diseases and cannot get it right.

In the video below, I will show you some of the tomato plants’ diseases and then take you through exactly how you can stop them in their tracks.

Diseases found in tomatoes

Tomato 1
Tomato 1

Many new gardeners start to grow their own fruit and veg; they plant the seeds and hope to harvest quality vegetables.

Tomatoes, in particular, are often chosen to be grown at home due it having simple needs like rich soil and lots of sunlight, and more, which can be further explained through this article I wrote on growing them. You can read it here.

tomato suffering disease

I don’t care what anybody says: Nothing is better than a tomato you grow. There’s something about it that’s different than a tomato you can buy. It’s a great thing.

Tom Vilsack

Unfortunately, nature never reads the same books as us, and we are soon introduced to the world of tomato diseases. But as a gardener, we don’t have to allow these to ruin our crops. So let’s get into what can cause us issues when growing our tomatoes and what we can do about it.

So many pests and diseases affect tomatoes. However, this episode will only concentrate on diseases. Some of the diseases that can challenge us are:

Damping OffLate Blight
Fusarium WiltTomato Leaf Mold
Bacterial SpeckPowdery Mildew
Verticillium WiltBlossom End Rot
Mosaic VirusBacterial Wilt
Grey Leaf SpotCorky Root Rot
Alternaria is better known as early blightWhite Mold

As you can see, there are a lot of diseases that can attack your tomato plants. This is even before we even get into the pest species. Let’s look at what these are and what causes them so that you can take action. A lot of these can be controlled with basic Hygiene, and others will require more work.

1) Damping off disease is something that can infect tomatoes

A multitude of viruses causes the damping-off disease. It typically affects young, healthy seedlings that are strong, but usually, there is a point of entry at the soil level where the plant was scratched when growing.

Cold, wet soils, overwatering, and overcrowding can all cause the damping-off disease.

Use clean, disease-free soils and space seedlings well. Be sure to avoid overwatering plants.

2) Fusarium wilt is a disease to look out for when growing tomatoes

Fusarium wilt is caused by a soil-borne fungus affecting many plant species. You may not see any signs of this until the plant reaches maturity; then, one side of the plant’s leaves turns yellow. Finally, brown stains appear over stems and leaves.

To prevent this, ensure good crop rotation is used to stave the fungus of a host. Also, avoid spraying leaves in cold weather or use a resistant variety of tomatoes. I have a detailed blog post, and a link to my blog will be on the end screen after this video, so stick around.

3) Bacterial speck is a disease that tomatoes can also get

tomatoes suffer bacterial speck

This is a bacterial infection that can reduce the size and yield of your tomato plants. You can identify it with lots of tiny little spots that are dark in color. These can be on the leaves and the fruit. The fruit will also appear sunken.

Fruit infected with this will be inedible, so that plant may as well be removed and destroyed. DO not compost this plant. There are varieties that are resistant to these bacteria if you suffer from them. But good soil husbandry and mulch can help prevent it.

4) Verticillium Wilt is a disease to look out for in tomatoes

Verticillium wilt is similar to Fusarium. It’s tough to eradicate from your soil if you have it. However, it would be much better not to grow any plant in the nightshade family in this area. It has very similar signs to Fusarium wilt but can affect many more plant species.

However, Verticillium Wilt is not as lethal as Fusarium Wilt because this can only turn older leaves turn yellow and have brown edges that turn crispy while the stems show signs of vascular damage.

Like Fusarium Wilt, avoid watering the leaves, utilize mulch to prevent splashing the soil onto the plant, and use resistant varieties.

5) Mosaic Virus is a disease that can be obtained by tomatoes

The Mosaic virus is loosely classed as a group of viruses; they cause the leaves to turn a mottled yellow-green color. In addition, they become wilted and fern-like to look at. This is caused by something infected coming into contact with the plant, Usually dirty sectors or clothing and other tools.

Good husbandry can help to prevent the spread of this around your garden. Do not smoke around these plants as tobacco can carry this virus. Reduce the number of people looking after the plants, and all affected plants should be destroyed and not composted.

6) Grey Leaf Spot is a disease that can dry off a tomato

Usually found in southern areas, this disease causes dark-colored lesions on the leaves, eventually drying and dropping off the plant.

Unfortunately this other than removing the plant and destroying it, there is not much that can be done. In addition, it affects many of the varieties that are available commercially, so consider older heirloom varieties.

7) Alternaria, better known as early blight is a disease that can be acquired by tomatoes

This infection is usually caused through the lower leaves when spores are splashed onto them during watering. Early blight can be identified as small dark irregular-shaped spots, usually with a yellow halo around them.

Early blight kills the leaves, causing leaf drop and can spread to the upper part of the plant and even the stems, which could develop into Alternaria stem canker.

Plants can usually hold off full infection long enough for a harvest. Although it will reduce the size of the crop.

As this pathogen is usually spread by spores being splashed onto the lower leaves, removing these leaves up to the first truss of fruit can help, along with mulching the soil around the tomatoes to prevent water splashing.

Drip irrigation or halos can help prevent this disease, but the one biggest factor is good ventilation and airflow. Air movement will drastically reduce the likelihood of your tomatoes suffering.

8) Late Blight is a disease that often wipes off tomatoes

This is the disease or infection that wipes out most gardeners. You can tell late blight by the wet and greasy-looking spots that appear all over the leaves and stems of the plant. They are grey-brown or black in color. In addition, the underside of the leaves will have a whitish fungal growth.

The fruit can also be affected and will appear sunken and have dark splodges of color over them. These fruits are no longer edible. Late blight spreads quickly and will wipe out your entire crop within a day if action is not taken.

What to do when late blight has attacked your tomatoes

burning tomato plants with late blight

If you find that you have late blight, then harvest all your tomatoes, whether they are green or not. Do not put these in your compost.

Although the composting process will destroy blight spores, it’s much safer to dispose of the tomato plants in another way which can be done by burning them.

Prevention is necessary as there isn’t really a cure for this disease. When planting, allow plenty of room between plants to allow good airflow. Warm, humid conditions are ideal for late blight, which is why keeping the surface of the soil dry to prevent humidity is a must.

Consider watering using drip irrigation or burying a drinks bottle into the ground and watering into that. Be mindful of rubbing against infected plants and transferring them to others. And mulching the surface of the soil can also help reduce spores splashing onto leaves.

9)Tomato Leaf Mold is a disease to look out for in tomatoes

This is very common in tomatoes grown under cover in greenhouses or polytunnels. Fungal spores cause it. This is due to high humidity and reduced airflow. It affects both the upper and lower sections of leaves, and while it does not kill the plant, it does reduce crop sizes and photosynthesis.

The tomato leaf mold creates olive green through to grey or brown splodges on the leaves, initially developing on the older leaves then spreading to the rest of the plant.

Like so many other diseases, good airflow is important, don’t overcrowd plants indoors and ensure humidity is low by mulching the ground and watering as suggested for late blight.

10) Powdery Mildew is a fungal disease to fear for tomatoes

Warm, dry climates cause this fungal disease, this fungal growth is a group of funguses, and some affect the upper portion of the leaves, while others affect the lower parts of the leaf. So occasionally, you may get both, and the entire leaf surface could have the infection.

You can tell this due to the spots of white fuzzy growth seen. Spores are very quick to spread and can affect all plants nearby, eventually killing the plant. Prevention is a must. Whole milk or even Neem or SB Plant Invigorator can be used as a foliar spray to help control it. At first signs, the infected leaves should be removed and destroyed.

11) Blossom End Rot and the reasons why this disease happens in tomatoes

tomato plants can suffer blossom end rot

This can usually be identified by dark spots that spread to the whole bottom half of the fruit; this destroys that fruit. It’s indicative of a calcium deficiency. The plant itself is fine but not absorbing enough calcium to support the development of the fruit.

There are two reasons for this.

  1. Not enough calcium in your soil but this is unlikely

2. Irregular watering of the plant has allowed the finer part of the root system to dry and wither up. This is the feeding part of the root system, and therefore the plant cannot take up sufficient quantities.

Once watering continues, these roots will regrow, and the plant can feed properly again. In the meantime, a calcium foliar spray can be used to provide the plant with what it requires. But do not overdo this as it can hurt the plant long-term.

12) Bacterial Wilt is a disease that when unchecked causes the death of tomato plants

It is usually found in the south of the USA, where at high temperatures, early signs are leaf wilt. Plants usually recover during cooler nighttime temperatures. But as the virus spreads, it will cause extreme wilting and the death of the plant.

Some varieties are resistant to this issue, and a simple internet search can help you identify them.

13) Corky Root Rot is a disease to look out for in tomatoes

The name of this disease comes from the fact that the large roots of the plants infected become corky in texture and lead to decay to the smaller roots. This disease is more rampant in cool temperature planting.

Since the root’s main responsibility is to provide for the nutrients and their uptake to plants, being infected by the corky root rot results in the plants affected growing small.

One way to combat this would be to utilize plants that were grafted to resist rootstock.

Conclusion on Diseases your tomato plants are suffering from

As you can see, many different diseases can affect your tomato plants at home. Most of these can be controlled with good husbandry, and others with a few products and feeds. Knowing what to look for and what to do when you spot it is of paramount importance.

I know this article may deter you from growing tomatoes, but I would like to personally tell you that growing them is rewarding and so worth it, especially when you have already harvested them.

Like everything, it just takes a little bit of research on how to grow them, their types of tomatoes, and things to look out for in them, which is covered in this FREE eBook that I wrote on how to grow them. So feel free to check it out.

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