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Powdery Mildew - Types of Plant Diseases and How to Treat Them Naturally

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17 Types of Plant Diseases and How to Treat Them Naturally

If you’re a farmer or plant enthusiast, be it for a hobby or your profession, then you’re all too painfully aware of the reality of plant diseases.

They can be caused by pathogens such as bacteria, viruses, fungi, and other organisms [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.

In this plant diagnosis guide, we’re here to help you sort through some different methods to remedy the situation.

Below is a list of the most common diseases of plants, their causes, and how to identify and treat them naturally.

1. Bacterial Canker

Bacterial CankerImage via compuventas.com.co

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.

Preventing Bacterial Canker

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 

Blossom End Rot - Problems Faced by FarmersImage via smallfootprintfamily.com

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 mulch 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.

Because blossom end rot isn’t a fungal or bacterial problem, fungicides won’t help here. 

3. Brown Rot 

Brown Rot - Types of Plant Diseases and How to Treat Them NaturallyPicture via weeklytimesnow.com.au

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 fruit and prune diseased branches ASAP. Additionally, keep the surrounding area clean of fallen fruits and twigs.

4. Club Root

Club RootImage via producer.com

Brassicas (cruciferous vegetables, mustard, cauliflower, kale, cabbages, etc.) are most at risk of this root killer.

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.

Preventing Club Root

Fungicides will not work, so focus on cleaning your garden and rotating your crops.

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 Fungus

Anthracnose FungusPhoto via almanac.com

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.

Moreover, you can use CEASE to treat the problem. This is a bio-friendly and non-toxic fungicide that won’t harm your crops or pollinators.

6. Damping Off

Damping OffImage via groworganic.com

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. With good air circulation, you stand a good chance of protecting the seedlings from this silent killer. 

7. Downy Mildew

Downy MildewImage via flickr.com

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

You can fight downy mildew by staking your plants and watering them early in the morning so they can dry out during the day.

Also, eliminate humidity and moisture around your plants and apply BANISH whenever necessary to assist in the destruction of the mildew. 

8. Early Blight

Early BlightPicture via pestnet.org

Early blight is a common bane 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. 

9. Fusarium Wilt

Fusarium WiltImage via fieldcrops.cals.cornell.edu

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.

Preventing 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 

Gray MoldPhoto via koppertus.com

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.

Getting Rid of Gray Mold

Stake plants and improve airflow. Water early in the morning with a soaker hose and allow plants to dry thoroughly.

BANISH garden fungicide can also help to provide the final oomph against the invader. 

11. Late Blight

Late Blight - Types of Plant Diseases and How to Treat Them NaturallyImage via thespruce.com

Tomatoes and potatoes get the worst of this one, a fungal infection that doesn’t occur until late into the growing season.

Late blight appears as water-soaked gray spots on older leaves which darken with white fungal growth beneath the leaves appearing.

Interestingly enough, this was the cause of the Irish Potato Famine in the mid-1800s [2].

Preventing Late Blight

Some plants are resistant to it, and early soaker waterings help prevent it from appearing. All debris must be destroyed following the harvest. 

12. Leaf Curl 

Leaf CurlImage via baag.com.au

This is an annoying virus that likes peaches and nectarines and is the bane of orchards everywhere.

Reddish areas develop thick puckering that causes leaves to curl in on themselves.

Preventing Leaf Curl

Rake the ground beneath the trees regularly and apply organic fertilizers while cutting back more fruit than normal. 

13. Leaf Spot

Leaf SpotImage via nwdistrict.ifas.ufl.edu

A pathogen that causes leaf spots to form on stone fruit trees and some kinds of vegetables like peppers, tomatoes, and lettuce.

Brown or black water-soak spots will start to appear larger and larger and run together, causing leaves to wither and dry up.

Preventing Leaf Spot

Make sure the soil beneath is kept clean and moist, applying generous mulch if need be.

Prune or stake for added circulation. 

14. Mosaic Virus 

Mosaic VirusPicture via almanac.com

It affects too many plants to list, but it often creates yellow, white, or green markings on the leaves and causes smaller leaves to wrinkle or curl.

Fruit appears warty and mottled when it comes in.

Preventing Mosaic Virus

There’s no cure for the mosaic virus, so make every effort you’d normally use to prevent it by cleaning, weeding, and staking as much as possible. 

15. Potato Scab

Potato ScabImage via allotment-garden.org

Potato growers are very familiar and annoyed with this one. It’s found wherever there are potatoes, much to the chagrin of the farmers.

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. The spores can survive indefinitely in low-acidity soil and can enter directly through the skin of any young tuber.

Preventing Potato Scab

To avoid, practice regular rotation of crops and keep pH levels at 5.2 or lower.

Make sure your potatoes have adequate irrigation methods and whatever you do, do NOT overwater. 

16. Powdery Mildew 

Powdery Mildew - Types of Plant Diseases and How to Treat Them NaturallyPhoto via almanac.com

Thankfully, powdery mildew is different from the others, in that it has a very limited host range.

They aren’t very likely to spread from their infected plant to another in close proximity if it isn’t a good match. But if your soil is low moisture in high humidity, you can expect to see it at some point.

This is a late-blooming disease that affects outdoor plants and creates raised, blister-like areas causing leaves to curl. It also creates a white, powdery substance on the upper surfaces of the leaves which prevents them from opening.

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.

You can also use milk sprays to further discourage the mildew from forming. This spray is made from 40% milk and 60% water as an effective home remedy that can actually be used on a wide variety of different crops.

There is also neem oil and BANISH that can be employed as an added bio-friendly technique.

Finally, destroy all crops after harvest. 

17. Rust Fungus

Rust Fungus - Types of Plant Diseases and How to Treat Them NaturallyPicture via britannica.com

Bad news; there are over 5,000 different species of rust on plants and they can attack almost anything from crops to lawns [3].

It looks like white raised spots on the undersides of leaves which become covered in rust-colored masses of spores and eventually cause discoloration and leaf dropping.

Good news; they can be dealt with.

Treating Rust Fungus

By watering early in the morning with a soaker hose, you give the plants time to dry off during the day.

Use a slow-release organic fertilizer to avoid excess nitrogen distribution.

You can also use Fungastop again for an extra layer of protection if the problem worsens. And a thick layer of mulch beneath the plants certainly never hurt.

See also: Tomato Plant Diseases (With Pictures) and Natural Treatments.


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 you can get into to protect your plants in advance from any organisms looking for an easy meal.

Just stay calm, use your natural green thinking, and get busy.

Sasha Brown

Blogger and lover of all things natural.

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