If you’re a gardener who loves tomatoes, you know the luscious pleasure of picking a ripe tomato and eating it, with juice running down your chin.
If you’re a gardener who grows tomatoes, you know that tomatoes are susceptible to a slew of problems. You know the challenge and reward of solving these problems.
But to figure out what to do about a problem with your tomato plants, you need to understand what the problem is. In this article, we touch on some of the common problems and practical solutions.
Can Poor Soil Cause Tomato Disease?
The right weather conditions and soil management will get you the bumper crop you want.
Yet, your tomato problems can start with soil.
The first effect of drought, for example, starts beneath the soil line as the root is the first to be affected.
Also, poor soil can be the culprit of some common tomatoes diseases.
During cool, moist periods, soil-borne bacteria can cause pith necrosis in your tomatoes. Soil with poor air circulation and poor drainage characteristics may cause fungal diseases.
As far as the soil types go, tomato plants can be cultivated in a variety of soil. Ideally, you should plant them in fertile soil containing a pH value between 6.5 and 7.
According to a paper published in the Scientific Scholar, the type of soil can affect the germination of the tomato plant. The seed germinates best in loamy soil. This is followed by:
- Compound soil (with 92.5% germination success rate)
- Sandy soil (with 87.5% germination success rate)
- Clay soil (with 57.2% germination success rate)
Check out this table of different soil types and their respective properties.
|Table 1: Shows the Result of Soil Analysis of Loamy, Sandy, Compound and Clay Soil|
Common Tomato Diseases
Wondering why the leaves on your tomato plants are dying? Or you want to know how to fix your tomato plants?
Let’s look at some of the most common diseases of tomato plants. This article will provide you with information about the causes and prevention methods.
Tomatoes are susceptible to fusarium and verticillium, two soil-borne fungal diseases that cause brown discoloration of the stems. Once a tomato plant gets either of these fungal diseases it’s too late to restore it to health.
When signs of wilting and leaves discoloration show, there’s nothing to be done. What was to be a healthy fruit will turn into a dead plant.
The infection starts when the fungi from the infested soil come into contact with roots’ wounds. At first, leaves turn yellow only on one side of the stem. But if you cut the stem lengthwise, you’ll see dark brown discoloration on the plant vessels.
How to Prevent Fusarium Wilt
Take the following steps to prevent fusarium wilt from damaging your tomato fruit:
- Buy resistant seeds or plants; they’ll be labeled VFN-resistant. You can find cultivars with resistance to races 1, 2, and 3 of fusarium wilt.
- Rotate crops and don’t plant tomatoes, potatoes, or peppers in the same place for three to four years.
- Raise the soil pH to 6.5 to 7.0 and apply nitrate nitrogen.
- Be sure to remove and destroy any diseased plants or plant parts—don’t toss them in the compost.
In humid climates early blight, another fungal disease, attacks tomatoes. Dark spots on leaves appear in concentric rings and usually start on the lower leaves.
Affected leaves then turn yellow and drop off, leaving the fruits exposed to the sun, which can cause sunscald. This, in turn, results in lesions to the skin that can become infected with mold. Once the disease spreads, it can affect ripening fruit as well.
Late blight is caused by water molds, whereas early blight is caused by a strain of fungi.
How to Prevent Early Blight
The best strategy to prevent early blight is to make sure the plants are spaced generously to increase air circulation. Keep leaves dry and off the ground.
Avoid overwatering and working in the garden when the leaves are wet. If you see diseased leaves, remove them to prevent the spread of infection.
Another way to fight early tomato blight, but also late blight, is by using baking soda and water. Take one quart of warm water and one teaspoon of baking soda and use it to spray the infected tomato patch.
The Tobacco Mosaic Virus
The tobacco mosaic virus causes leaves to crinkle and become mottled in color. It produces a greenish-yellow mottling and stunting. As for the tomatoes, they look brown on the inside.
The spots on leaves form a mosaic pattern, hence the name of the virus.
Once affected with the disease, tomato plants have slim chances of survival. And again, there’s no cure. So, make sure to destroy any infected plants.
How to Prevent Tobacco Mosaic Virus
The virus spreads mechanically when tobacco comes into contact with the plant.
So, the prevention methods come down to sanitation. Here’s what you can do to prevent the spread of the virus:
- The virus is spread through contact with tobacco, so smokers should wash their hands thoroughly before working in the garden.
- Use TMV-resistant varieties of tomatoes.
- Never smoke near your tomato plants.
Blossom End Rot
Blossom end rot causes a watery spot at the blossom end of the fruit that turns into a sunken, black wound. Brown spots on the infected plants often appear as the fruit ripens.
Lack of calcium due to water stress or high levels of nitrogen can produce blossom end rot. Also if the soil pH is too low the plant won’t be able to absorb the calcium from the soil.
How to Prevent Blossom End Rot
The best way to protect fruit damage caused by this disease is to use a mulch to preserve soil moisture. You can also have a soil test done, which will tell you how much nitrogen (if any) to apply to the soil.
Also, try applying:
- Lime and gypsum to the soil, but only after the soil test has been done and you’re positive on how much to use.
- Crushed eggshells to your compost to boost calcium levels in a natural way.
- A calcium chloride-based foliar spray to stop the spread of the disease mid-season.
Tomato Insect Pests
Various insects affect tomato plants and fruit. Yet not all pests and insects are harmful to your tomatoes. Some are even part of an ecosystem that promotes the health of your tomato plant.
Yet, as any seasoned gardener would reason, it’s better to be safe than sorry. Check with your agricultural extension office to see which pests are most problematic in your area.
Now, let’s zoom in to some of the most common plant problems garden pests can cause.
Tomato hornworms are large, distinctive, green caterpillars that eat the leaves at the top of the plant. Even though they are three to four inches long, their green coloration gives them good camouflage.
They feed on tomatoes leaving the leaves and fruit spotty and chewed.
How to Prevent Tomato Hornworm?
These garden pests change form as they go through developmental stages. Ideally, you’ll be familiar with the stages. That’s how you’ll be able to prevent them from eating through your tomato leaves and fruit.
- Adult hornworm moths lay eggs in late spring.
- Caterpillar larvae develop their cocoons 4-6 weeks after hatching.
- Cocoons spend their winters in the soil.
- Adult moths emerge from the cocoons in late spring when they start laying eggs again.
That said, your garden will typically get infested with hornworm in mid-summer. That’s when the insects grow into caterpillars and the tomatoes are in the growing season.
Here are some of the prevention methods which will help you protect your tomato plants:
- Pick the caterpillars off if you see them.
- If the problem gets out of hand, use bacillus thuringiensis (BT) for organic control.
Aphids cluster on the tips of the tomato plant shoots or suck the juices out of the undersides of the leaves. They produce a sticky substance called honeydew that attracts more tomato plant problems.
Aphids can also transmit virus disease to tomatoes and cause a decline in your crop yields.
How to Prevent Aphids?
Spraying with insecticidal soap usually takes care of aphid infestations. Like aphids, psyllids are small insects that suck plant juices and can be controlled with insecticidal soap.
There are other organic control alternatives such as horticultural oil and rotenone dust.
You can also try fending off the pests by importing beneficial insects. Yet, it will take two weeks until they outnumber aphid populations.
Cutworms cut off small plants near the soil surface. They damage young tomato seedlings at the stem and as a result, they collapse.
Yet, these pests won’t mind feasting on mature plants as well. Once you spot holes in leaves of older plants, you’ll know what’s wrong with your tomatoes.
These garden pests have a nasty attack strategy: they attack only at night. So, as you might imagine, this can be a hassle for the gardener.
How to Prevent Cutworms?
To prevent cutworm damage to your tomato fruit you can:
- Place collars around young plants or protect them with aluminum foil.
- Plant later in spring after the caterpillars have finished feeding.
- Go on a caterpillar hunt after dark when they’re at work.
According to the Australian Primary Industries and Regional Development website, another way to work around this destructive pest is to:
“Control with evening sprays of bacillus thuringiensis, spinosad, diazinon, cyfluthrin, or pyrethrin.”
Other Tomato Problems
Herbicides can damage the leaves and fruit of tomato plants. They can spread to the garden when applied to nearby lawns or from using grass clippings from herbicide-treated lawns as mulch or in compost.
There’s a simple strategy to help you prevent herbicides from contaminating your tomato plants. Make sure you wash your gardening clothes regularly so that herbicide residue that builds on them doesn’t damage healthy tomatoes.
Volumes have been written on tomato problems. In general, planting the right varieties for your location, feeding and watering properly, and watching for pests are good ways to prevent many troubles.
Again, do not treat until you know what’s causing the problem.
For more information about specific problems and treatments, check out these websites:
Pictures of tomato disease and insect problems from Texas A & M Extension help with identification and control.
More photos and control recommendations, from the Colorado Cooperative Extension.
Video on common tomato problems and solutions from the University of Nebraska Extension.