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Treating blight on plants


Tomato Blight Treatment and Prevention Tips

While tomatoes tend to thrive in home gardens, they can sometimes be plagued by disease.

Three different types of blight may strike – early, late, and Septoria blight.

What’s a poor gardener to do?

By keeping a close eye on your plants, and starting treatment as soon as possible if you detect one of these insidious diseases, there may be hope for your crop!

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This guide will show you how to distinguish between these diseases, prevent them, and treat the infection.

Here’s what’s ahead in this article:

What You’ll Learn

A Rundown of the Culprits

There are three types of blight that affect tomato plants. Spots on the leaves are the first indication of each of these infections. However, they all have their quirks that allow you to distinguish between them.

Symptoms of early blight.

Two are caused by fungi – early blight (Alternaria solani) and Septoria blight, aka Septoria leaf spot (Septoria lycopersici).

The third – late blight (Phytophthora infestans) – was considered a fungus for 200 years. However, it is now known as a water mold (or oomycete, to be technical).

This organism is what caused the Irish potato famine, forever altering Irish and American history.

Late blight.

Alternaria and Septoria can devastate your crop at home, while late blight is an extremely serious infection that can decimate whole tomato fields.

Late blight is such a menace that you are advised to inform your county extension agent if you find it in your garden.

Read more about identifying late blight here.

Early blight and Septoria are often confused, since each of these infections causes the leaves to yellow and die. And both of these infections start on the lower leaves.

However, it is possible to tell them apart. Here’s how:

  1. Alternaria produces lesions with concentric rings that can also affect the fruit. They appear on the lower leaves first.
  2. Septoria leaf lesions, on the other hand, usually present as numerous tiny brown spots that grow and spread.
  3. Advanced Septoria leaf lesions contain dark colored fruiting bodies that look like grains of pepper. Alternaria does not produce any comparable structures.
  4. The lesions of late blight look different from those caused by fungi. They start out as little spots that look like they are soaked with water before spreading into large purple-brown blotches that appear oily.
  5. This water mold can also infect the fruit in cases of late blight, typically starting on the shoulders.

Check out our in-depth guides to learn more about early blight, and Septoria leaf spot.

Prevention

Prevention is your best bet in the battle against all of these diseases, and in some cases you can nip them in the bud (or leaves, or fruit…).

While these diseases are all caused by different types of microbes, there are common steps that you may employ to prevent infection.

Plan Your Garden

Before you start planting, plan the layout of your garden with the help of your gardening journal.

Locate your tomato plants away from areas where you want to grow potatoes or other nightshades.

Check your seed packets to establish mature sizes of the varieties you are growing. This allows you to ensure adequate spacing between plants, to prevent the spread of disease.

Grow Resistant Varieties

When choosing your plants, particularly if you know blight has been a problem in the past, choosing to grow resistant varieties is recommended. Information about resistance to different types of disease is typically included in tomato cultivar descriptions.

Resistance to early blight is usually labeled “EB” on tomato seed packets.

Keep in mind that resistance is not the same thing as immunity. Tomato plants that are resistant to early blight can sometimes contract the disease anyway.

Resistance to late blight is more difficult for plant breeders to select for, since the water molds mutate quickly and have been able to overcome resistance in the past.

‘Magic Mountain’

However, the cherry tomato cultivar ‘Magic Mountain,’ available from Burpee, is resistant to both early and late blight.

‘Iron Lady’ and ‘Defiant’ are two cultivars that are resistant to early, late, and Septoria blight.

Though it is not quite at the level of being resistant, the ‘Sweetheart of the Patio’ cultivar is tolerant of late blight, and it’s well-suited to growing in containers.

You can read more about this variety and find out where to purchase seeds in our roundup of the best cherry tomatoes to plant in your garden.

Stake Your Plants

Promoting good airflow will also help to reduce the levels of moisture in the interior of the plant. Staking your plants prevents fruit and foliage from coming in contact with the ground.

Check out our guide to learn more about using the Florida weave to support tomato plants.

Fertilize

Ideally you should test your soil before you plant, to make sure the pH is between 6.5 and 7.5, and to determine whether there are any nutrient deficiencies.

At this time, before your seeds or transplants are in the ground, you should amend your soil accordingly.

After that, don’t fertilize your tomato plants again when they are young. Wait until they are well established and blooming before you fertilize again.

Fertilizers with an NPK ratio of 5-20-5 or 4-12-4, with the highest level of phosphorus in comparison to the amounts of nitrogen and potassium, are good choices.

If you need to add nitrogen, on the basis of your soil test results, also apply calcium nitrate at the same time. This will help to avoid blossom-end rot.

Do not add urea or ammonia as nitrogen fertilizers, as tomato plants are very sensitive to ammonium toxicity. This can result in yellowing of the leaves and poor root development.

Remove Weeds

Members of the nightshade family serve as hosts for all of these diseases. Such beloved crops as tomatoes, potatoes, and eggplant are all members of this family.

It also includes common weeds like nightshade and jimsonweed, as well as ground cherry.

All of these types of plants can harbor the pathogens, so be vigilant, and purge them from your garden! This includes volunteer tomato plants as well.

Irrigate at Ground Level

Watering your plants from above can invite infection. This is particularly true in the case of sprinkler irrigation, but even using a watering can can be an unhealthy practice if water is showered onto the foliage.

Instead, use a soaker hose to provide drip irrigation at the ground level. If your plants are growing in containers, make sure you water at the soil line.

Avoid Wet Conditions

Since all of these diseases are spread by water, resist the urge to work with your tomato plants in any way if they are moist. This includes moisture from rain, dew, and irrigation.

On wet days, it’s best to skip checking your plants for pests or picking any pests from the leaves. Do not prune when plants are wet, and wait to stake or train plants that require additional support or adjustment until they are dry.

You should even avoid going out to harvest tomatoes in this type of weather. If an extended period of rain is in the forecast, consider picking the fruit in advance of inclement weather, or wait until plants have dried again.

Apply Mulch

This may not seem like an obvious step, but an application of mulch can also help to prevent contaminated soil from touching the leaves.

Another benefit is that it can reduce the amount of humidity around your tomato plants. Lower humidity means any spores present are less likely to germinate and cause an infection.

However, you should wait until the soil has warmed up to apply mulch. Add three to four inches of organic mulch around the base of plants about three to five weeks after planting.

Grass clippings, wood chips, or straw that is free from weed seeds are all good choices.

Remove Infected Plants

Be vigilant about removing infected plants. In the case of late blight, all plants, including those that are not showing symptoms, should be removed and destroyed.

If you had a blight infection at some point during the growing season, bag up all the tomato plants and remove them from your property.

Do not add any of the plant material to your compost pile, and be sure to remove all parts, including the roots and any fallen debris.

Growers with fields should disc them deep underground, so that they will decay.

Rotate Your Crops

It’s human nature to want to keep growing plants in the same place where they have done well in the past.

However, this practice can favor infection.

Even if you didn’t observe any infections the previous season, the pathogens could be lurking at low levels, waiting to strike at an opportune moment. Rotating your crops will prevent this from happening.

You should rotate your nightshade crops every year, just to be safe. If you had a problem with Septoria blight last season, make that every two to three years.

And if you absolutely cannot rotate your tomato plants since you are short on space in the in-ground beds, consider growing them in containers instead.

If you are reusing the containers, sterilize them with 10 percent bleach first, and always use fresh soil.

In the case of late blight, Jean Ristaino et al, in an article published by the American Phytopathological Society, recommend planting non-host crops in a two to three-year rotation.

Treatment

It is possible to control Septoria if you catch the infection early enough. Aggressively remove the infected leaves and purge them from your property.

Do not add the material to your compost pile, and dispose of it in the trash, away from your garden.

Simply removing infected plant matter will not control early or late blight. You will need to use fungicides to manage these infections.

Fortunately, you have several options.

You can use the same kind of fungicide to treat each of these diseases. Apply them every seven to 10 days throughout the season.

If your weather is conducive to the spread of these diseases (i.e. humid and/or rainy), you can also consider using preventative sprays before the onset of an infection.

While the products described here have all been shown to be effective, fungi can develop resistance to fungicides if they are used frequently.

Check your plants periodically to ensure that the treatment is still working. If it isn’t, you may need to change which type of fungicide you are using.

Fortunately, all of the fungicides recommended here are in different classes, so you should be safe switching between them.

Organic Fungicide

If you are looking for an organic fungicide to use, you are in luck!

Bonide Liquid Copper Fungicide

Copper will kill all of these organisms. You can buy Bonide Liquid Copper Fungicide from Arbico Organics.

Synthetic Fungicide

Many of the fungicides commonly used to treat tomato diseases will treat all of these blights.

One thing to remember with the fungicides listed here is that you should stop using them five days before you plan to harvest your tomatoes.

Your choices include:

1. Chlorothalonil – Bonide Fung-onil Concentrate, available from Amazon

2. Maneb

Biofungicide

One of the microbes commonly used in the biological control of plant diseases is effective against early blight.

It is a strain of the bacterium Bacillus subtilis, which is also known as CEASE Biological Fungicide, available at Arbico Organics.

Learn more about using B. subtilis in your garden with this guide.

Inspect Your Plants Frequently

As with any infection, your best odds of success for treating these tomato diseases is largely dependent on whether you are able to catch them early enough.

Make a point to inspect your tomato plants on a regular basis, so that you can identify an infection in its early stages. The official term for this is “scouting.”

While you might be able to stop Septoria blight from spreading if you catch it early enough, that is not the case for early or late blight.

But you can eradicate the plants from your garden to prevent further spread, and take steps to protect any tomatoes that you wish to grow next year.

Starting an aggressive campaign with fungicides as soon as you detect an infection – or even preventively, if the conditions are conducive to the spread of blight – may help to save your tomato crop.

Have you had to fend off one of these diseases? If so, let us know how you fared in the comments below.

And read on to learn about other disorders that can strike tomatoes:

© Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Product photos via Arbico Organics and Burpee. Uncredited photos: Shutterstock. With additional writing and editing by Allison Sidhu and Clare Groom.

how to identify and treat early blight

Tomato blight, in its different forms, is a disease that attacks a plant’s foliage, stems, and even fruit.

Early blight (one form of tomato blight) is caused by a fungus, Alternaria solani, which over-winters in the soil and infected plants. Affected plants underproduce. Leaves may drop, leaving fruit open to sunscald.

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What does early blight look like?

Early blight’s Latin name is sometimes confused with a form of tomato rot, alternaria, a different tomato problem altogether.

To muddle matters further, early blight is occasionally mistaken for Septoria leaf spot because the two diseases infect tomatoes at the same time.

You'll recognize early blight by these characteristics:

Dark, concentric spots (brown to black), ¼ - ½” in diameter, form on lower leaves and stems. Early blight is marked by tell-tale rings.

Fruit can also be affected; spots often begin near stem of fruit

Lower leaves turn yellow and drop.

When does early blight affect plants?

How do you control and treat early blight?

Other diseases (such as late blight, Septoria leaf spot, and gray leaf spot) can also be controlled by these biofungicides and fungicides, so application is multi-purpose.

How do you prevent early blight?


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How to cure root rot? — ASM-AGRO

Root rot is a plant disease that all farmers are trying hard to fight. We have prepared an article for you in which we will talk about the types of root rot, ways to control pathogens and treat the plant. Also in this article you will learn how to identify a particular type of mushroom in the field.

Farm workers rarely subdivide root rots, and because of this, they cannot solve the disease problem of their plants. Correct diagnosis - 90% success!

There are a large number of varieties of root rot, but we will talk about 5 types:

  • Fusarium,
  • Helminthosporium,
  • Rhizoctonia,
  • Cercosporella.

    • We do not consider other species, because they are not significant for winter wheat.

    Root rot of wheat: symptoms

    All these diseases, except for cercosporellosis, affect the roots of plants, and the symptoms at the initial stage of the lesion are approximately the same.

    Absolutely all of the listed types of fungi infect the basal part of the stem. As a rule, root rot can turn into root rot when it was poorly developed. If the development of root rot is serious, the plant simply dies.

    But in our time, people actively use dressing agents, so very often root rot turns into root rot only when it is not sufficiently restrained.

    What does root rot look like?

    Visually, only ophiobolosis is quickly recognized, it causes focal white spike. If you see spots with a diameter of 1-2 meters on the field, especially in the lowlands, where there is more moisture, then most often this is an ophiobolosis. The rest of the rot is usually evenly distributed over the field.

    If you do not have deep knowledge of botany, then the only correct way to make a diagnosis is to order a laboratory analysis. You can determine that the plant is affected by root rot on your own, but you can find out the exact name of the pathogenic fungus only after analysis.

    Do not save and neglect the services of the laboratory, otherwise you can not only start the field in the current season, but also get problems the next year.

    Root rot: different causes

    So, unlike all other types of fungi, cercosporellosis affects only the root part, therefore it is a root rot. And very often cercosporellosis is confused with rhizoctoniosis. As a result, ineffective drugs are used.

    If you think you have rhizoctonia in your field, will you work with fungicides? Not really, because it's completely pointless. But against cercosporellosis, using fungicides for vegetation is a good solution. Even if symptoms are already present, treatment will help stop the spread of the disease to the rest of the field.

    Plant Health Rating Chart

    There is a chart where each plant can be scored based on its appearance.

    With a score of 1, you can take no active action. Manifestations that correspond to this assessment do not affect the yield and will not bring losses to the economy of your farm. With a score of 4 points, the plant can be said to die.

    And at what point, at what stage should you start solving the problem of root rot? We can say that actions at any stage practically do not make sense.

    Cercosporellosis is controlled by fungicides at the stage of onset of symptoms, it is possible to protect yourself from ophioblight by prevention, and other types of rot cannot be directly affected on the field.

    If root rot has appeared in your field, it is most likely the result of mishandling last season.

    Root rot agents

    But root rot control is still possible and is mainly associated with plowing and seed treatment. In general, seed preparation is one of the main processes that gives you an advantage over diseases.

    There are several ways to protect the field from root rot, but not all of them are effective for every disease:

    The table shows what works and what does not work for each type of root rot:

    Ophiobillosis is not controlled by seed treatment, as is cercosporellosis. Cercosporellosis is a root rot, so seed treatment does not affect the development of the pathogen.

    Fungicides can be used to treat the field with all types of root rot, but in the case of Fusarium, Helminthosporium and Rhizoctonia, this will be a simple prevention. It will be possible to cure plants with fungicides only from ophiobolez and cercosporellosis.

    Opheobolosis is controlled by strobilurins, cercosporellosis is controlled by any good triazoles. Triazoles must be in sufficient concentration and with the original active ingredient in the composition.

    Root rot prevention is the best cure

    The most important control method that limits the development of any variants of root rot, including root rot, is the incorporation of plant residues.

    But in this case it is very important that the crop residues completely rot before new crops are planted.

    If the residues remain in the root layer or a little lower without air access and do not rot, this means that after a year, when plowing, the entire infection will be realized again.

    This technique is found in no-till. The whole task of the no-till is the transformation of plant residues and the preservation of humus. With proper no-till, the residue should rot before the next crop is planted.

    Root rot fungicide in case of ophioboleza

    External damage to the root system by ophioboleza cannot be seen externally. It occurs in a very short period, and at the same time the fungus remains in the soil for 10-15 years.

    Ophiobill is not transmitted by seeds. Under anaerobic conditions of high humidity, about once every 4-5 years, it gives an explosion in development. As a rule, this manifests itself in the south of Russia and in the Central regions, and much less frequently in other regions.

    It is possible to predict the occurrence of ophiobolez if there was at least 40 mm of precipitation in May. Then the disease begins to appear not as an isolated case, but as a defeat of a large part of the field.

    What drugs can block? Well suited fungicides from "Makhteshim" or preventive treatments with strobilurins during the period of the beginning of the release into the tube - the end of tillering. The amount of working fluid must be sufficient to shed the product to the root collar.

    Root rot: treatment for Rhizoctonia

    Rhizoctonia blight looks like spots with sclerotia inside the spot area and is very easy to distinguish from Cercosporellosis, which has ocellar spots and is completely light. The tips of the roots of the plant with rhizoctonia look like sharpened pencils.

    And if cercosporellosis can be treated with any fungicides and triazoles, then they do not work with rhizoctoniosis. The only option for controlling rhizoctonia is seed treatment with carboxamides.

    Rhizoctonia as a root rot rarely occurs because it requires a large supply of infection. But if this did happen, then most likely there were spikes there a few years ago, and the non-decomposed straw was deeply embedded.

    Fusarium root rot: treatment

    Fusarium is accompanied by a large number of symptoms at all stages: from the beginning of germination to ear fusarium. Main symptoms: browning of the roots, browning of the root collar, first internode, black nodes throughout the plant.

    But it is important to understand that Fusarium is just an indicator that the plant is weakened.

    How to control? Seed treatment with fludioxonil, prochloras, or triticonazole.

    Root rot: treatment of helminthosporiasis

    Helminthosporiasis is a simple, as it used to be called, ordinary root rot. It is controlled by any triazoles during seed treatment.

    As a rule, Helminthosporiasis does not cause root rot. This is a soil fungus that infects the roots and weakens the plant when it is under stress. And this, as a rule, is a spring disease.

    So: treat seeds before sowing, carry out preventive work with fungicides and cover up crop residues. If you follow these tips in a comprehensive manner, then you can protect the field from root rot as efficiently as possible.

    Another moment of seed processing is drying in a conveyor grain dryer. This does not protect against rot, but it prepares the seeds for sowing, and the likelihood of infection with parasites and fungi is reduced. Why drying should be done with a conveyor dryer? You can find out in this article: Conveyor Grain Dryers: Working Principle and Benefits

    Gardener's Tips for Treating Root Rot in Houseplants - LemonTree - Beautiful Houseplants

    Sometimes, if a plant has been watered, it becomes obvious that it needs to be restored after this. The leaves begin to wither and turn yellow, and the whole plant seems to be on its way to death. You are trying to fix a watering problem, but nothing seems to help. Chances are your plant is suffering from root rot.

    What is root rot?

    Root rot can have two causes. One of them is prolonged exposure to water during overflow, which can cause the roots to die due to lack of oxygen. As they die, they begin to rot and fall off. The rot can spread to healthy roots and kill them, even if watering conditions are corrected.

    Another cause may be the presence of a pathogenic fungus in the soil. The fungus may have been inactive in the soil for an indefinite time. And then, when the plant has been watered once or twice, it suddenly begins to multiply. Root rot from a fungal infection causes the roots to die and rot.

    What does root rot look like?

    If you're not sure if a plant has root rot, you might be wondering what root rot looks like? If the plant is slowly withering and the leaves are turning yellow for seemingly unknown reasons, you will be tempted to check its roots.

    How to identify root rot? To do this, remove the plant from the soil and feel the roots. Roots affected by root rot will look black and feel soft. Affected roots can literally fall off the plant when you touch them. Healthy roots may be black or pale, but they will feel firm and pliable to the touch.

    Root Rot Treatment

    If the problem is overwatering (single or prolonged) that has caused a root rot fungus outbreak, you must act quickly. Treating root rot as soon as possible will give your plant the best chance of survival.

    To start treating root rot, remove the plant from the soil and wash the roots under running water. Wash off as much soil and affected roots as possible, but at the same time, be careful with the plant itself.

    Then use sharp, clean scissors or a knife to cut off any other affected roots. When dealing with root rot, you will need to remove a significant amount of the root system if the plant is severely affected. If this is the case, then clean the knife or scissors with alcohol and also cut off 1/3 to 1/2 of all the leaves on the plant. This will give the plant a better chance of growing roots, as there will be no need to maintain a large number of leaves.

    Learn more