In this article, we’re here to help you sort through organic treatments and home remedies for plant diseases.
Infectious plant diseases are caused by pathogenic organisms such as bacteria, viruses, and nematodes [1]. Fortunately, you do have natural ways to get rid of the problem.
Losing even a few units of crops to diseases can be devastating if they’re your full income. Plus, all the time, money, and care you spent in building your fields and gardens.
Below is a list of the most common diseases of plants, their causes, and how to identify and treat them organically.
1. Bacterial Canker
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One of the main bacterial diseases in some fruit trees, this cherry tree killer likes to show up right after the trees have been wounded. It does so either through pruning or something else that causes a gash in the bark.
Bacterial canker takes the form of sunken, water-soaked, and gummy-looking lesions on the trunk or twigs.
Bacterial Canker Treatment
One organic disease control measure for bacterial canker is to prune trees during blooming for fast healing. Also, remove weeds and grass from around the base of the tree.
Additionally, Monterey Complete is a great natural treatment to use against bacterial canker.
2. Blossom End Rot
You’ll find this dark brown, sunken-in patch in tomatoes and peppers most commonly. It is not a disease, but a plant disorder caused by a lack of calcium or inconsistent watering.
Preventing Blossom End Rot
Mix bone meal or oyster shells into the soil to bring up the calcium levels. Additionally, use mulches to help keep soil evenly moist and retain this moisture for long periods.
With mulch, your water will be distributed more evenly, preventing blossom end rot from easily taking hold.
3. Brown Rot
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This is another fruit killer and it’s very common. Brown rot mainly affects stone crop fruits like plums, nectarines, cherries, and peaches.
Fruits will show circular brown spots with rotting areas producing clumps of gray spores.
Getting Rid of Brown Rot
Remove infected fruits and prune diseased branches ASAP. Additionally, keep the surrounding area clean of fallen fruits and twigs.
4. Club Root
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Brassicas (cruciferous vegetables, mustard, cauliflower, kale, cabbages, etc.) are most at risk of this fungal disease.
Once it implants, it causes the roots to form improperly and swollen, preventing water and nutrients from being properly absorbed.
The plants around the base will turn brown or yellow and start to die. Also, the spores can survive in the soil for many years, so treatment is crucial.
Controlling Club Root
Fungicides will not work, so to prevent this garden disease, focus on rotating crops and cleaning your garden.
Additionally, weed carefully and keep your soil’s pH neutral or slightly alkaline, testing it with a Soil Test Kit frequently throughout the season.
5. Anthracnose
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This one is caused by the fungus Colletotrichum lagenarium [2]. It generally affects tropical foliage plants, succulents, trees, and woody ornamentals.
Treating Anthracnose
Prune dead and infected plant parts and destroy them. Also, remove infected plants from the garden.
Another way to control this plant disease organically is to use CEASE. This is a bio-friendly and non-toxic fungicide that will take care of the problem. Moreover, it won’t harm your crops or pollinators.
You can also make a natural fungicide for trees and vegetables by combining 3 tablespoons of apple cider vinegar with a teaspoon of liquid soap and a gallon of water.
Shake well and use this homemade fungicide spray to treat anthracnose and other fungal diseases.
6. Damping Off
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This fungal disease mainly affects seeds and new seedlings. Unfortunately, there’s no cure once it’s taken hold, as it causes new growth to become mushy and water-soaked, killing them at the base.
Preventing Damping Off
Avoid overcrowding your crops and use well-drained soil. Moreover, with good air circulation, you stand a good chance of protecting the seedlings from this silent killer.
7. Downy Mildew
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This mildew appears on leaf upper surfaces as yellow to pale green spots, with the undersides of the leaves featuring white and fluffy fungal growth.
The downy masses will show up just after a rain, disappearing again when the sun comes out.
Getting Rid of Downy Mildew
To get rid of this plant disease naturally, try staking your plants. Also, water plants early in the morning so they can dry out during the day.
Additionally, eliminate humidity and moisture around your plants and apply BANISH whenever necessary. You can also use Monterey organic copper fungicide spray to treat downy mildew.
8. Early Blight
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Early blight is a common disease of tomato and potato plants. It creates brown spots in a bullseye pattern on the older leaves, turning them yellow and causing them to wither.
Preventing Early Blight
Pruning and staking, as well as keeping the soil clean and debris-free gives them a good chance of survival. Furthermore, by adding organic compost, you can also further protect the vegetation from soil spores.
Fungastop organic garden fungicide can also work wonders in protecting against this fungus.
You can also make a DIY fungal spray for plants using baking soda. Combine one teaspoon of baking soda with a teaspoon of liquid soap and a quart of water.
Shake well and use this homemade anti-fungal spray to coat affected plants. Baking soda will kill some soil fungi and diminish the effects of others.
9. Fusarium Wilt
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This soil-borne pathogen attacks all kinds of crops like potatoes, eggplants, peppers, and tomatoes.
Infected plants wither, yellow, and die. However, the symptoms don’t usually show up until late in the growing season.
Controlling Fusarium Wilt
There is no treatment, only to remove stricken plants from the garden when discovered. You should also treat the soil with a method like soil solarization.
10. Gray Mold
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Gray mold shows up as a cluster of gray spores that attach to the fruit or vegetable in question and spread rapidly. It usually develops in high humidity and causes areas on fruits to rot.
Treating Gray Mold
Stake plants and improve airflow. Additionally, water early in the morning with a soaker hose and allow plants to dry thoroughly.
Arber Bio Fungicide can also help to control gray mold on plants.
11. Late Blight
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Tomatoes and potatoes get the worst of this one, a disease that doesn’t occur until late into the growing season.
Late blight appears as water-soaked dark-green or purple-brown spots on leaves. Interestingly enough, this disease was the cause of the Irish Potato Famine in the 1840s [2].
Controlling Late Blight
Remove volunteer plants from the garden and practice good crop rotation to help prevent late blight. Also, destroy all debris following a harvest.
12. Leaf Curl
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This is an annoying fungal disease that affects peach trees, almond trees, and nectarines. It is the bane of orchard farmers almost everywhere.
Leaves start to curl and look severely distorted. They may also have a purple or reddish cast.
Treating Leaf Curl
Prune trees and spray them entirely with a copper fungicide.
13. Leaf Spot
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Bacteria or fungi mainly cause leaf spots to form on trees, shrubs, and some vegetables like beets, tomatoes, and lettuce.
Brown, yellow, orange-red, tan, or black spots will start to appear on leaves, which can later weaken the plant.
Preventing Leaf Spot
Remove fallen leaves from beneath and avoid overcrowding plants. Additionally, water crops at the base and keep leaves dry.
14. Mosaic Virus
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The mosaic virus affects too many plants to list, but it often creates yellow, white, or green markings on the leaves and causes smaller leaves to appear wavy.
Preventing Mosaic Virus
There’s no cure for the mosaic virus, so make every effort you’d normally use to prevent it by disinfecting tools and removing infected plant parts.
15. Potato Scab
Image via allotment-garden.org
Potato growers are very familiar and annoyed with this one. Symptoms resemble dark brown patchy areas that can look like raised warts.
Potato scab can affect a small section or completely envelop the whole potato. Moreover, the organism that causes it can survive indefinitely in soil that is slightly alkaline.
Preventing Potato Scab
To avoid, practice regular rotation of crops and keep pH levels at 5.2 or lower. Also, make sure the soil is moist but do not overwater.
16. Powdery Mildew
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Powdery mildew is likely to spread from an infected plant to another in close proximity if the wind is blowing.
This late-blooming disease affects outdoor plants and causes the leaves to turn pale yellow or brown. It also creates a white, powdery substance on the upper surfaces of the leaves.
Getting Rid of Powdery Mildew
It’s best to plant your seedlings in sunny locations with regular pruning and stakes applied. Make sure to keep the ground debris-free and use a thick layer of added mulch.
Moreover, you can make a homemade milk spray of 40% milk and 60% to further discourage the mildew from forming. Or, make a natural fungicide for powdery mildew by combining 3 tablespoons of neem oil with a gallon of water.
Alternatively, JMS Stylet Oil and BANISH are reasonably priced organic fungicides for powdery mildew.
17. Rusts
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There are over 5,000 different species of rust disease on plants and they can attack almost anything, from crops to lawns [3].
Rusts appear as yellow or rusty-brown spots on leaves. It then becomes covered in rust-colored pustules and eventually causes discoloration and leaf drop.
Treating Rust Plant Disease
By watering early in the morning, you give the plants time to dry off during the day. Also, clear away all debris from in between plants.
Additionally, Bonide Sulfur Fungicide is a product organic farmers use to control fungal diseases like this one. It gives an extra layer of protection against plant rust.
You can also make a cheap organic fungicide following the baking soda recipe above.
See also: Tomato Plant Diseases (With Pictures) and Natural Treatments.
Takeaway
The variety of plant problems out there is truly mind-boggling, especially since some of them literally can’t be stopped once they take hold.
However, there are always healthy habits and biological methods of plant disease control to deal with the issues.
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