Common Plant Diseases

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Common Plant Diseases


We all know how difficult it can seem at times just to keep your plants alive. If it’s not pests that destroy them then they get hit by various diseases. I this article I intend to discuss some of the most common diseases.

I will discuss how to recognize a disease and how to control it. But before I start on the list I just want to give you a word of advice on prevention measures you can take.

I have often been to gardens that have been ravaged by insects, rust, mold, black spot and so on. I have spoken to the owners of these gardens who have no idea why their plants seem to be picked on the most.

Well here’s a short list of some reasons that disease in particular will hit some gardens and not others.

1). Your soil is infertile.

Make sure you prepare your garden soil correctly, before planting. A healthy garden is a happy one, and it all starts with

soil preparation.

Have you added fertilizer? Fertilizers come in many forms. I prefer the organic types. Particularly ones that are slow release and have added trace elements and minerals.

Have you added manures? Manures act as a soil conditioner as well as providing low levels of NPK.

Have you added compost? Compost also conditions the soil and provides certain levels of NPK.

Did you complete a soil test to check the Ph? Most soils require a ph from slightly acidic through to slightly alkaline. There are the exceptions where some plants like a high or low ph, but you can easy adjust the levels to cater for these plants specifically.

You can adjust soil Ph by using products such as Lime, Dolomite (to increase ph), and iron chelates (to decrease it)

When you add the manures,composts and ph adjusting products, you will need to incorporate them well into the soil structure.

2). Your plants aren’t getting enough light.

This is a common problem in well-established gardens. Far to often people over plant their gardens at the initial building stage. They put in far to many trees and bushes not realizing just how tall and wide these plants will grow.

When we first purchased our current property you couldn’t actually see the house. There were far to many large trees blocking out the sun. Most of the under story plants had died and only shade loving ones remained.

The house was moldy and damp and the garden was very sick. We removed about a dozen large trees and let in the light. It has taken us ten years but we finally have a healthy mostly disease free garden.

3). You have purchased plants that are really not suitable for your climate.

If you live in a wet, cold area then you need plants that are able to cope with the conditions. For example, most succulents and cacti prefer dry conditions. Other plants love the wet conditions and hate heat and dry.

Always ask questions at your local garden center when purchasing plants. Also, do some research on your PC or cell phone. Check out exactly what conditions plants thrive in before purchasing them.

4). You have purchased sick plants.

Make sure any plants you buy are healthy looking. Check the root ball in the pot. If the roots are heavily matted I would avoid purchasing them. They can be teased out before planting but if you don’t do this correctly they may struggle and become susceptible to diseases

Healthy plants can fight diseases better than unhealthy ones so give them the best possible start in life by implementing the methods I have mentioned above.

For further information on Manures and composts, soil preparation etc., click on any or all of the following links.


Now we Can Take a Look At the List of Common Plant Diseases.


1. Black Spot. (Diplocarpon rosae)

This is probably one of the most devastating of the fungal diseases that can affect Roses as well as other plants. It can start of as a small dark spot on a leaf and the leaf turns yellow and eventually falls off. It is always better to be diligent with inspecting roses for this disease and removing any infected leaves, placing them in a throwaway bag and disposing in the rubbish bin.

Don’t be tempted to place the leaves in your compost as this can spread the disease.

Black spot is worse in humid areas where it thrives in the moist conditions. Even though it is a fungal disease it is dependent on wet, damp, warm conditions to spread.

At one point in our lives we spent several years living in a dry arid, almost desert area. My wife planted a rose garden that absolutely flourished as long as it was watered every second day. We never saw any sign of black spot and the plants and blooms were magnificent.

Our current garden is located in the sub tropics some twenty miles (Thirty odd Kilometers from the coast.). Black spot and other fungal diseases are a constant issue on our Roses.

What can I do To help control the Black Spot Disease?

There are a number of steps you can take to help control black spot.

1). Remove any leaf that shows signs of the disease. As stated earlier, the first signs are a small dark brown to black spot which gradually is encircled by a yellowing of the leaf until, eventually the leaf drops off.

The fungus spreads quickly to the other leaves and plants, infecting the plant and eventually reducing the plants vigour

2.) Always wet the ground and not the plant. If you are putting in an irrigation system, stick to drip lines that water the base of the plant and don’t touch the leaves.

3).Keep the plant healthy by fertilizing on a regular basis. We supply our Roses with some type of slow release organic fertilizer once a month. As our plants in the sub-tropics flower all year we like to add Sulfur of pot ash to the mix twice a year. This not only helps to flower but strengthens the stems and helps fight disease.

4). Purchase only those plants that are strong and healthy and are breed for disease resistance.

5). Use a natural fungal spray once a week. (see below for a recipe). Another natural spray is a ‘Bordeaux mixture’, which is a mixture of lime and copper sulfate. Neem Oil is also a good natural product to use for any fungicide related disease and will also help control certain insects.

6). Use a Chemical solution. If you have an extreme situation then you can think about using a chemical fungicide such as Mancozeb or

A Natural Recipe for Black Spot:

Fill a five liter ( or approx 1 gallon ) sprayer with water.

Add 1 heaped tablespoon of Bicarbonate soda (baking soda).

Add 1/3 rd of a teaspoon of dish washing liquid.

Mix well and spray over leaves and stems. Make sure you cover the whole plant. Both sides of the leaves, and the soil at the base of the plant to the drip zone

You will need to spray the leaves twice a week while the weather is wet or humid. Diplocarpon Rosae thrives in wet, damp, moist conditions, particularly when the daytime temperature fall below 80 degrees (27 c).

If you can keep the sprays up to the plant during this type weather you will find that you can reduce the spraying once the climate becomes warmer and drier.

Make No Mistake!

Black spot can be debilitating to Roses in particular. It can, and will, kill Rose plants. Black spot is also known to mutate meaning that even so called resistant Rose varieties can succumb to this terrible disease. All the more reason why you need to be diligent.

. Keep your Roses as healthy as you can.

. Use some form of control, preferably an organic one, regularly.

. Wet the soil when watering, not the plant.


. Never plant a new Rose in a spot where an old one has died. I have been successful in doing this myself, however, I removed about two square feet of soil and replaced it with new healthy soil.


2. RUST ( Pucciniales )


Rust is caused by a pathogenic fungi that comes in many diverse forms that are specific to different plant species.

Rust is another disease that can completely destroy a plant. It is probably one of the best known among common disease terms and can be described as being a fungi that produces red, brown or black spores in Pustules.

These Fungi, as mentioned, are specific to certain plant species and each type may only affect one to two plant varieties.

About twenty years ago I operated a Daylily (hemerocallis) nursery, daylilies are an extremely tough, hardy, fiber rooted perennial. They had very little disease or pest issues and came in thousands of colors and types.

Our nursery was thriving, until rust disease arrived. It decimated our plants and made our business unprofitable. Eventually people discovered organic ways to control the fungi, sadly this came too late for us and we were forced to close our nursery.

Most Daylilies can outgrow the disease if you use control methods. However, the control has to be diligent as the rust will reappear during times of high humidity and rain.

If you have Daylilies that look like they might be struggling, check under the leaves. The rust will show as an orange powder. Should you notice this powder, carefully remove all leaves, cutting the plant back close to ground level.

Place the leaves in a plastic bag and throw away into the rubbish bin. Do not compost as the spores can survive the composting treatment.

This is one disease that I would suggest you bring out the heavy artillery. Using fungicides such as Zineb, mancozeb, lime sulfur or copper can control it.

Also, when cutting up clumps and moving them to a new location, I like to dip the plants for one hour in a mixture 0f 1:20 Chlorine and water, that being one part Chlorine and 20 parts of water.

Household bleach works well for this. Make sure the plants are completely submerged for the length of time mentioned.

Other plants that can suffer from Rust include:

A). Gerberas: This shows up as a creamy-colored pustule under the leaves.

B). Snapdragons: Spray these with a fungicide every ten days. Alternate between different spray types. Make sure you commence the spray program from the time you plant the seedlings.

Once the plants have finished flowering pull them out and either dispose of them by placing into a plastic bag and into the rubbish bin, or burn them

C). Beans: Bean rust attacks the whole plant, the beans included, but it can be first seen on the leaves which become covered in red, yellow and / or brown pustules. If you notice this disease in your beans my advice would be to remove and dispose of the plants immediately as mentioned above. Fumigate the soil with a relevant fungicide and don’t plant any other related legume in that particular spot.

There are many other plants such as Hostas and members of the myrtle family, that are affected by rust. In some cases the spores can completely kill of the plant or tree and in others the plants seem to fight back and survive.

Unfortunately, rust is a growing world problem that is affecting more and more plant species every year.

3). Mildews:

Powder Mildew. (Erysiphe polygoni and E. cruciferarum)
Downey Mildew. (Peronospora sparsa)


There are two main types of Mildew that affect the garden.

A). Downy Mildew.

B) Powdery Mildew.

Both these can be debilitating to plants. In most cases they will cause the plant infected to die and they will also spread to other plants.

How Do you recognize these mildews?

When a plant is infected with Downy the mildew the upper surfaces (or top of) of the leaves) will become blotched. If you turn the leaf upside down you will clearly notice the formation and origin of the blotchy patches.

Eventually the whole leaf will turn yellow and drop of.

Powdery mildew reveals itself as a light gray coating on young leaves, buds and shoots.

These are not diseases you want to ignore as they can destroy most garden plants, in particular vegetable plants and annual flowers.


If you find this to be far to drastic, and it is a measure I would undertake, then you will need to use a fungicide such as Mancozeb or an Eco based fungicide.

Other preventative measures you can take are:

A). Make sure you don’t plant seedlings to thickly. If you have, then thin them out, It’s far better to lose a few this way then to find you have lost the lot. Plants require good air circulation and over planting can cause a host of different issues.

B). Don’t use overhead sprinklers or water the plants on top with a hand held sprayer. Always try to water plants at the base. This helps minimize any spread of the mildews. It’s also better to use a good drip system.

C). I also suggest that you water your plants in the morning and not the afternoon.

4). Root rot. (Phytophera – or Armillaria(Honey fungus)

The two most common forms of root rot are Phytophera and Armillaria, the later is known as Honey Fungus and is prevalent in many countries around the world.

Root rots are one of the most serious of all plant diseases. It’s above ground. symptoms include a sudden stunting of growth and a tendency for the plant to wilt, and in severe cases, to die back completely.

Root rot is carried by a fungus in the soil, and it affects all plants from annual flowers to large trees. I have personally seen many avocado orchids decimated by Phytophera.

When the plants stems rot at ground level it is known as crown rot.

The fungus is most active in moist damp soils and those soils that have bad drainage. It can also develop during periods of extended heavy rainfall, even on well drained soil

Some Preventative Measures to stop it spreading Include:

A). Soil Sterilization. This can be an expensive option and would need to be carried out by experts. The downside of sterilization is that you will have to rebuild your soil structure and health from the ground up. excuse the pun.

B). Drench the soil with an organic fungicide or fungicides such as aluminium tris (O-ethyl phosphonate)

C). Remove all infected plants and replace with those resistant to this disease. If you live in humid areas, such as the tropics or subtropics, then I would stick to growing those plants that come from these areas.

There You Have It. Part One of: Common Plant Diseases.

You need to remember that the most basic measure to prevent or control any fungal disease is to plant either disease resistant species or those that belong to the environment you live in. If you live in the sub tropics or tropics then an intense wet season can kill off most cool climate annuals.

You must also prepare your soil diligently. A good garden will require a healthy, friable and well draining soil.

The old saying ‘prevention is better than the cure’, is mandatory within any garden environment.

Happy Gardening. Jim

If you would like to know more about gardening for beginners, have a look at this post.

Look out for the next installment in this gardening series.





Jim Kulk


  1. Thank you for writing about black spot. It has come timly for me and I am going to try the natural remedy and I have the ingredients in my pantry which is really handy. I am attempting to go all natural in my garden and  get rid of the non-organic herbicides and pesticides and just go all natural. I like too that you have added preventative measures and I will keep them in mind when considering what to plant in my gareden – I have bookmarked your site 🙂



    • Thank you for visiting Rina. Yes, organic is always best. Good luck with your remedy. Jim

  2. Thanks for your post. Recently we have 2 indoor plats which are dying. These plants have been with us for about 5 years. I know they don’t have soil and light issues. They are sick this year.

    I suspect that they suffer from root rot, since we see that the color of the leaves are becoming yellow and the plant don’t grow any for two months. We spent $400 and bought these 2 plants, would like to help them to survive the current illness. We just change the soil for them last weekend. It is good idea to drench the soil with fungicides.

    It is kind of you sharing this useful information. 

    • Hi Anthony. In the case of an indoor plant, yes I would drench it, just in case. Unfortunately it isn’t easy to keep indoor plants alive at any time but usually persistence pays. All the best. Jim

  3. Hi Jim,

    I really enjoyed this since I am a gardener and have experienced some of these conditions. I love that you try to use organic solutions where possible but honestly tell us where the “big guns” are needed! I understand what you mean. 

    My Dad believed in organic gardening and I still try to use natural solutions. I have used my own spray (similar to yours here) for roses. It worked! Our wild roses always thrive in a hot summer so I can imagine what you are saying about the desert vs. moist climate. 

    I hate mildew. We had downy mildew last summer. It just wouldn’t quit! I see why you recommend just getting rid of the affected plants. 

    I have seen rust occasionally but it is not usually a big problem here in Alaska. It affects wild tree leaves more than domestic garden plants. 

    Thanks for this info. I look forward to your next post!


    • Thanks for visiting my site Jessica. Unfortunately Rust is affecting much of the native forests in our country as well. Particularly with myrtle species. Organic sprays are always the best, but sometimes more is needed. Jim

  4. Wow I had no idea that plants could rust. This post is definitely an eye opener. Thankfully I haven’t had any issues like these to deal with as far as my plants are concerned. I did however, forget to water two newly planted ones and they died so I have to replant new ones and use some sort of reminder to wet them appropriately; at the root. 

    I am however, curious as to why the rust is becoming such a problem. Your article stated that it’s becoming a world problem, why is that? Also my space is limited and I want to start using some pots for a few vegetable plants. Is there anything special I need to pay attention to doing something like this?

    • Hi Vanessa. I wish we knew the answer to that question. It could be environmental issue, or maybe we have over hybridized plants. It’s probably no different then with us humans, the diseases that kill us and plants keep mutating. All the best. Jim

  5. Dear Jim,

    I love gardening and we have a small garden at our house. We recently switched to organic foods and you know very well it’s expensive, so we grew some vegetables in our garden itself. I believe it’s a pleasure and blessing to eat the vegetables we grow.

    While doing some research on the plant diseases I came across your helpful and informative post. I knew nothing about agriculture but I have love and passion for it. So I started to learn online and try a few things in my garden.

    After reading your post, I realized that I am not even doing the basic things (However still the mother nature is providing me results) If I follow things correctly the benefits will be even more.

    Going to start from the basics… Soil preparation.

    Rust is a big challenge for us and the information you shared is an eye-opener. OMG, I did the mistake of composing those leaves under the soil.

    You not only discussed the problem, but you have provided with the solution as well which is amazing. I am bookmarking your post for future reference.

    Happy Gardening!


    • Thank you Paul. I’m glad my article provided you with some new information. Gardening is always a process of gaining knowledge and implementing it . Jim 

  6. Jim, 

    I am glad I have read your article.  You have gone into great detail describing not only about the common diseases but what you recommend to get rid of the disease.  Could you tell me what NPK is?  I really like how you discussed examples of diseases and circumstances that happened to you first hand.  This builds trust in accepting your recommendations.  Also, I was wondering if leaves on my green beans in my garden that have turned yellow mean anything?  I was thinking possibly due to over watering?



    • Hi Michelle. Thanks for reading my article. NPK simply means the Nitrogen, Potassium and Phosphate levels either needed or available in fertilizers for plants. Jim

  7. Plants not getting enough light is a good thing to consider. You don’t want to plant too much like you said as taller trees and plants will shade other plants. Climate is something to consider also. People can tend to forget that not all plants do well in all environments. It’s important to do research, especially in dealing with something like plant disease. Plants are amazing. They have minds of their own it seems and some are stronger than others. Survival of the fittest definitely exists in plant world. I think mildew is most common where I’m from, so I will take this knowledge along with me out there, thank you!

    • Thank you for your comments. I hope you can find good use for the information in the article. Jim

  8. When I was just an elementary pupil, part of our curriculum in school was to have a garden for growing vegetables. I remember, it was my garden that was made a model garden for the whole class because I was able to grow healthy vegetables. But after a few weeks, spots started on the leaves just like what’s shown in the pictures here. I thought it was a normal condition for plants, that plants normally undergo such a problem as they age. But today, I got this amazing discovery that it might have been caused by fungal infection. Thanks for this enlightening article. 

    • Thank you Gomer. I’m so happy you got something out of my article. All the best. Jim

  9. Excellent article.  I have two potted fruit plants that appear to suffer from rust spots…the pathogenic fungi as you stated.  I may have a solution for the problem thanks to your article. I would prefer not to destroy them, as they were able to produce oranges last season and I was very please with the amount of crop we were able to get from both of them.  

    I have used a fungicide on them before and the results were mixed..short term but the rust returned this year for some reason. This may be difficult to deal with as you say the problem is getting worse every year, unfortunately.  

    Thanks for the heads up and possible solutions. Great article, timely also.

    • Thank you Tim. Yes, the rust problem is becoming a big issue world wide. Jim

  10. This is exactly what I was looking because our rose plants in the garden are all infected with black spots on their leaves. We love the roses. We cannot use chemical spray because of young kids.
    Thank you for sharing the natural recipe for black spots, and the tips for taking care of rose plants.
    I like your articles, will come back for more 🙂

  11. Gardening happens to be one of my hobbies, I have been taking care of the roses in the garden for a year now and I’m beginning to notice some brown spot on some of them, I initially knew it wasn’t a good sign and I don’t want to cut it off, but I guess i have to now so it doesn’t get to kill all plants in my garden. Thanks for this informative article 

    • Thank you for your comments. I wouldn’t cut the plant, just pull any bad leaves off and through them in the bin. Jim

  12. Hey Jim!

    Great job on the site! You can really tell that you put in some hard work. You were very informative and it was super easy to read and understand. 

    I really like the fact that you not only named the disease and list it’s facts but you also listed ways to fix it.Not just one way, multiple ways!

    Great Job,

    Miss D

    • Hi Delia. Thank you for your comments. I appreciate you reading my blog, and I’m happy you were able to get some good information from it. Jim

  13. Hello Jim, this is a really good post, I am so eager to kick of my garden and I came to your site to see what  plants diseases are. You have written everything really well and I understand perfectly, I also got extras on what to do to prevent the plants from having the disease. I already ordered for fertiliser and I think they’ll work pretty well. Thanks for the enlightening.

    • Thank you Jackson. I’m glad you got some information from my blog. All the best


  14. Hi Jim, I’m glad you wrote about black spot among the common plant disease. I just started gardening some months back and I’ve been noticing the black spots on my plants. I was baffled at first and I just decided to research on it if it could be a disease and here I am being confronted with it. I will take into consideration what you have said and try to fertilize more often and pay closer attention to them. Thanks for your help. I really appreciate.

  15. Hi Jim, hope you don’t mind me asking a question. Was going through this list of plant diseases and can’t seem to find one befitting the condition of my money plant. I grow them indoor and inside pots of water. They used to thrive very well until some of the leaves started turning yellow in recent months – one by one. 

    It looks like a withering process but it’s happening at a very fast rate than usual. I haven’t made any changes to sun exposure and changing the water frequently. Do you think some kind of disease is lurking or am I overthinking? 

    Thanks for your tips. 

    • Hi Cathy. It sounds like they’ve been getting to much water. They hate to get  their feet wet. I would change the potting soil mix and check for any rot on the roots. If you find any the cut or scrape it off and sprinkle cinnamon on the roots before replanting. Cinnamon acts like a natural fungicide. Jim

  16. Thank you for this informative article.  I love plants and flowers but let’s say my thumb is anything but green.  I have realized it is better if I do not get attached to any plant in my house as I always kill them.  I have cherry tomatoes in hanging baskets.  I buy them every year from a great greenhouse and they are. full and healthy……until about 2 weeks on my balcony.  All the leaves dry up and fall off but I still get tomatoes.  I have tried watering consistently but that doesnt help.  Suggestions?

    • Hi. Maybe you are over watering them. I have several blogs written on the myth of having to have a green thumb. Gardening is like any other part of life. You can learn how to do it. Jim

  17. I learn something new every day.  It makes sense that plants can get diseases since it’s an organic life form but that doesn’t make it all the less surprising.  I’m not a gardener expert so I always thought plants needed water and nothing else.  It’s refreshing to educated on the subject a little.

    • Hi. If only it was true that they only needed water. It would make life so much easier for us gardeners. Jim

  18. I have 3 aloe vera plants and 2 of them are having black spots. But I never thought that removing the leaves can help and I am a huge fan of watering the leaves. I am gonna change these 2 things and see how my plants will improve. 

    I think that knowing what causes diseases is great. Because you can be at a place where you don’t have access to a specialist to help you and instead of saving your plants you may end up destroying them. 

    You did me a real big favor here. I have discovered a lot with your post and I am gonna do my best to improve the way I take care of my plants.


    • Hi. I’m glad you enjoyed my blog and that you learned something from it. Thanks Jim

  19. I remember when I was young, our school had taught us the love of planting. I studied in that grandparent’s green province of Bataan for one year there I learned the things I have read in your article. The teacher basically told us to use grounded manure of Water buffalo we called carabao as fertilizers. We used to clean up the Barrio of manures even the fresh one was taken and dried in a designated place, (the teacher said). All Grade 3 students where I was in, were was tasked to plant eggplants, my elder brother who was in grade 5 they planted lettuce. We learned the fundamentals of making the soil not acidic though it was not termed that way and the teacher showed us what types of ‘sicknesses’ the plants could have. Our teacher showed how to spot what you have mentioned mildews. I have seen black spots I used to cut the affected leaves until my plants looked skeletal. I confessed I was not a ‘green thumb’ kind of person but I do love gardening. Fortunately, my wife is good at plants including flowering and decorative plants. Root rot is dominant here in our little garden (it’s our balcony). I also saw plant disease you called rust at my parent’s garden. Thank you for putting specific names to all the common diseases of plants I knew a long time back and an awesome bonus to know some remedies like mancozeb lime sulfur, natural fungi spray, etc. Thank you for putting me back in a rather nostalgic part of my life. 

    • Thank you for your wonderful reply. I enjoyed reading the story of gardening in your youth. I’m glad you enjoyed my blog and that it brought back memories


  20. I like green plants a lot. I have chosen a place in my house and plants there. I have discovered a lot with this post and me gonna do best to early improve the way I take care of my plants. I didn’t know about soil pH before. However, when planting my plants I must monitor the soil pH.
    Thank you for this informative article. We hope to discuss such matters later.

    • Hi Snigdha. Gardening is a fantastic past time.

      I hope you learn heaps from my blogs. All the best. Jim

  21. Hi Jim, I got hooked on the first thing “soil being infertile”. I was reading about that lately but on a grande scale – a lot of people suggest that our soil is getting degraded because overuse. This poor quality of soil results than in food quality, less nutrients, more watery and just not as good as it used to be.

    You know a lot about gardening, plants and soil – would you say that’s the real issue, the thing happening to our soil?

    A bit of topic but I’m really interested in it,


  22. I am always super impressed when someone who can garden and understand all the aspects of gardening do what they do like you have described here. As much as I love gardening, I’m also not very adept at knowing the ins and outs and details of diseases, crowding, and positioning of plant placements and everything else that gardens need. I’m one of those who over plant when the plants are still small and find it hard to judge how big they will get for when they are grown and established. I love reading about gardens and trying to learn what I can. I guess for me it’s about staying focussed on learning about my little garden and transfer what I learn from my reading to my gardening if that makes sense. Thanks for sharing your wealth of knowledge in the garden. 

    • Thank you Kat. If I have helped you to be better able to look after your garden them I’m pleased. Jim


  23. Hello Jim!
    You have written an awesome article. We all have the desire to make our own garden or some plants of beautiful flowers. I also am one of them.But seeing them dying soecially when we actually do not know particularly why this happens, is a great matter of sorrow. However you wrote so nicely and have risen very important points and reasons for this. poor soil condition, proper fertilization, proper light all are so important. And I liked to know about the diseases. specially the black spot. Never thought about it. Thanks again. it will be very helpful.

    • Thankyou for reading my blog on gardening diseases. I hope it inspired you to go out into the garden. Jim

  24. Gardening can be pleasurable to most folks. Even therapeutic. A way to take your mind off things. Many folks take pride in their garden, plants and flowers. There are many beautiful plants and flowers that, as a gardener, you want to take great care maintaining them. 

    Just like a human body, plants can obtain diseases too, which can hinder healthy growth in leaves and other parts of the plant and flowers. Sometime I’d watch gardening shows which display the many types of plants and flowers, that folks deal with. They discuss how things should be done regarding it’s proper care to prevent diseases. I always wondered if plants all develop the same type of diseases?  Are some worse than others? Enquiring minds want to know!

    • Hi. Yes, some plants are better at handling disease then others. I personally believe that many plants have been over  hybridized and have become week with little disease resistance. Thank you for reading my blog. Jim

  25. Hi Jim, 

    How happy I was to come across this great post. You have given so much good advice which is going to be very helpful.

    We, in the Western Cape of South Africa, have had to make big changes in the way we garden due to extreme drought. 

    After moving into a Retirement Village, I planted pots of roses and for the first two years, all went well and then they developed root rot and died. The drainage was more than likely the problem. 

    After losing the roses in this way, and due to the drought and having to cart washing up water downstairs to water the plants, very back-breaking, I changed the garden into an indigenous garden and find this much easier to manage and very worthwhile. 

    Have also found that having the soil analyzed is crucial to a healthy garden. Thank you for all the gardening tips.


    • Thank you for reading my blog Jill. Yes, it’s always better to grow plants that suit the environment. All the best. Jim

  26. Hi Jim, thanks so much for coming up with this list of common plant diseases. It is extremely helpful for someone who is new to gardening and isn’t a green thumb like me.
    My husband purchased a house with a very wide garden. He loves planting. Me, I am trying my best to be helpful here and there. Unfortunately, I am not a green thumb so I leave all the planting on his part. But since I still want to have an active part in the garden, my role is to help in the maintenance of the plants and garden, like watering, pulling out weeds and having a close eye on the state of every plant.
    Reading your article made me go back to my garden and check on a few of the plant diseases that I have already noticed growing before especially on our roses! Thank you for the advice and tips on how to control the spread of such disease.
    With this knowledge, my eyes will stay open and ready for the hunt of suspicious infectious illnesses that might disturb the beauty of our garden.
    Thanks once again!

  27. Hi Jim, thanks so much for coming up with this list of common plant diseases. It is extremely helpful for someone who is new to gardening and isn’t a green thumb like me. My husband purchased a house with a very wide garden. He loves planting. Me, I am trying my best to be helpful here and there. Unfortunately, I am not a green thumb so I leave all the planting on his part. But since I still want to have an active part in the garden, my role is to help in the maintenance of the plants and garden, like watering, pulling out weeds and having a close eye on the state of every plant. Reading your article made me go back to my garden and check on a few of the plant diseases that I have already noticed growing before especially on our roses! Thank you for the advice and tips on how to control the spread of such disease. With this knowledge, my eyes will stay open and ready for the hunt of suspicious infectious illnesses that might disturb the beauty of our garden. Thanks once again!

    • Hi Denise. I wrote an article about a year ago discussing the myth if having a green thumb in gardening. Anyone can learn how to garden . As with all things in life it takes training, persistence , and a live for it. You will find that if you find that if you consistently wander around the garden looking for issues, you will become more and more interested in your surroundings and, eventually your thumb will turn green. Jim

  28. Hi  Jim

    It is always good to be reminded about common diseases as they are becoming harder and harder to treat. This is because a lot of fungicides that have been used in the past, so you have to rely on prevention which is not a easy thing. In the future gardeners will need to grow disease resistant varieties, which are becoming more prevalent in roses.

    For example blight is now a difficult disease to treat and the only method that can be used in blight areas is to grow blight resistant varieties. You do not have much of a choice . I believe a lot of disease can be prevented if the plants are more healthy in the first place. 

    What is the best treatment for fungal diseases, if all effective fertilizers have been banned?



    • Hi Antonio. There are still many fungicides available for use. But the problems if disease can be limited by purchasing healthy, strong plants and developing healthy soil structure before planting. Jim

  29. Okay, now I am worried… My sister sent me a bonsai as a gift a few weeks ago and after reading a lot of articles, I think that it has root rot.

    I can’t throw it away because it was a gift for my birtday. Should I talk with an expert for soil sterilization? How expensive could this measure be?

    • Hi Harry. I gather your bonsai is in a shallow pot. If so you may need to remove the plant , clean off all the soil and cut away any rot. Dip the roots in a fungicide before reporting into fresh potting mix. Make sure you don”t over water the plant. Jim

  30. Hi Jim,

    Awesome article, I really enjoyed the reading!

    I had a beautiful plant a few years ago, and then she got sick because we moved and went to the north of the country and she just died. Now I have plenty of cactuses in the garden but one of them is sick now. So by instinct, I’ve cut the cactus, and I am waiting to see the result:) Do you think I did the right thing? Well, I know it’s a bit late, I should have asked this before:) Anyway, without mistake, we don’t learn.

    Looking forward to hearing from you

    Thank you for this useful post!

    • Hi Daniella. Your cactus should be fine, just don’t over water it. Jim

  31. I’ve benefited a lot from this post. Before reading it I knew nothing about the other options for buying fertilizer.
    From now going forward I will buy organic fertilizer.

    It’s good to make some informed decisions. It gives such a good feeling. Now I know that there are different preventive measures I can take to stop my plants from catching diseases.

    I have 2 Heartleaf Philodendron potted plants I bought 5 years ago from Homebase. Surprisingly, one has grown long but the other has not grown much.

    Your post has opened my eyes. I now know what might have caused this problem. It could be due to lack of light, the type of soil and the way I’ve been watering the plants.

    Also, I didn’t do some research to make sure I buy the right plant that is suitable for the room climate. Thanks so much, I have bookmarked this post for future reference. 

    • Hi Zegu. You will now be able to O grow healthy plants. Thank you for reading my blog. Jim

  32. Thank you for the information Jim.

    As I am about embark on the backyard agriculture and planting, this gives me some really good insight on what to look out for with new and old plants, soil issues and contamination, plus how to fertilize.

    The lighting and how your plants are placed is something that as I see as being crucial to cultivating a lovely backyard garden.

    I wil definitely be very careful in my initial plant purchases, using these key notes as a guide of what to look out for.

    • Thank you Shane. I hope you build a beautiful backyard garden and that my article helps you to achieve this. Jim

  33. Hi! I’m grateful I found your post. Here you not only help us identify what’s been going on with our plants but you also teach us how to solve the issues. In my case, my plants are not receiving enough light. And I agree, that’s the problem when others planned the garden and were not considering how wide these plants would grow. I’ll also follow what you did in your own garden. Thanks.

  34. Hi, your review about list of common plant disease is very educating, it made me to learn about plants and how to keep them, based on the facts in your post I can manage a garden and am glad I have you to contact if am having any difficulty about it, I will also share your post for my friends to learn from your post.

  35. Few years ago, i did a little research on root rot; Root rot is one of the most commonly diagnosed disease problems of woody plants in landscapes in North Carolina. Each year there are dozens of shrubs and trees that have one of the “big three” root rotting diseases: Phytophthora root rot, Thielaviopsis black root rot, or Armillaria root rot. A very insightful post you’ve got here.


    • Thank you Jordan. Yes, root rot is another fungal disease that is becoming a problem world wide. Jim

  36. Hi Jim,

    Great post. I agree with you that these plant diseases are quite common and a nuisance, too. Having grown up in the country side, I saw most of them. Like at around this time of the year (July, Aug) when the tropics experience cold weather (not lower than 15 deg Celsius, though), potato blight was our worst enemy. Is potato blight’s black spots similar to the black spot disease you’ve mentioned in the post?

    Mildew, aphids, rust and root rot are all preventable if one was to take your advise to prepare the soil adequately, and have the remedies you’ve mentioned ready before ever planting. I actually did not know that fertile soil is that “immune” to lurking plant pathogens. Thanks for the eye opener.


    Boniface from AndroidBix

    • Hi. Thanks for reading my blog. Potato blight is vastly different to black spot in leaves. All the he best . Jim

  37. Thank you for this very interesting and informative review. I enjoy gardening especially on a Saturday as it is not only a hobby but I used it as part of my keep fit exercise program.

    some of the conditions you have pointed out is key as i was not aware of these diseases and was always struggling with black spots. What I have been doing wrong is letting the leaves remain on the ground for fertilization believing that once its rot it would be fine.

    I am not a professional, I do it for fun and I am very happy to have read your article as this will give me the edge in preparing and producing more healthy crops.


    • Hi Maxine. Thank you for reading my blog. I hope you enjoyed it and learned something new. Jim

  38. It had never crossed my mind that a plant could have a disease or some kind of sickness! I know they are organisms, but this is definitely news to me. 

    I have some plants around the house myself, aloe vera and some roses, so I will take this into consideration when taking care of them as well as any other plants I may acquire in the future.

    Thank you Jim!

    • Hi Anthony. Yes, plants can suffer from many diseases, those I’ve mentioned in my blog are only a few. Look out for further articles that I hope to add in the future based around other diseases that can cause issues to our plants. All the best. Jim

  39. This is perfect for those of us who don’t have a natural green thumb! I have orchids and have managed to keep them alive and growing, but one of them gets occasional yellow spots on the leaves. The spot turns dead-ish but doesn’t spread. Could it be a fungus or is that something that isn’t self-containing?  It doesn’t sound like rust – but I’m curious if you have any ideas. I’m a bit bummed that the reactions to many of these are simply to eliminate the plants, but it makes sense if it is to not spread. Thanks for the tips!

    • Hi Hilary. It’s difficult to diagnose them without seeing the plan. Just make sure you don”t Overwater them, and make sure you give them a feed of liquid orchid fertilizer every month or so. Jim

  40. Hi

    Very interesting and informative post for those who loves to do gardening.I am a new gardener.Just started to do gardening. But the Problem I am facing my trees are not growing. I am from UK,so as you know what type of wether here,I try to give enough sun light when is good weather but still facing this problem. I lost couple of trees.Same problem,either they don’t grow or within few days they dies. So what you think could be reason?Just need to mention I haven’t seen any insect in my trees.

    • Ty here could be a number of factors your trees won’t grow. Is your soul acid or alkaline. Have you added fertilizers and manures. Were the trees healthy when you bought them! Etc., Jim

  41. This is a highly informative article on plant diseases and how layman like is can easily identify and prevent them.

    Honestly, there are some plant diseases I never good too much of my attention in my vegetables garden to like the black spot. In fact, there is this myth I actually believed in that vegetables especially leafy ones taste better with black spot. 

    I wonder who started such myth encouraging people to feast on unhealthy plants. At least, thanks to this article of yours, I now know how devastating they are and the preventive measures to take to avoid them and other diseases.

    My question is, aren’t compost and manures the same thing? Correct me if I’m wrong please as I always thought compost is a type of manure.

    Overall, thanks for putting together this article, it is indeed a very helpful one.

    • Hi. Thanks for reading my article. No, composts and manures are not the same thing. Manures are and animal waste, whereas compost us made up of leaf litter, grass, vegetable scraps and manures. Jim

  42. This article has so much valuable information for me that I bookmarked it so I can come back as often as I need to. There are so many common plant diseases that are out there and things to watch for that it can be difficult to figure out the problem. 

    Especially if you are dealing with environmental conditions that may be unfamiliar, it can be difficult to determine what is going on. I was raised in the mid-west of the USA, and we had gardens every year that we used to grow the foods that we ate during the winter months.

    Right now I am living in Dubai, where the sun is extremely hot for much of the year. The growing conditions and plants that will do well are much different. The information here will help guide me in making sure that my plants have the best chance of surviving and thriving. 

    Thanks for putting this together, there are a number of diseases that we have to watch for here in Dubai, and you have made the chore a bit easier. The actionable advice for each of the diseases will help for sure. I am looking forward to putting the advice to good use immediately!

    • Thank you Dave What a wonderful part of the world you live you in. I’m so pleased that my blog was helpful to you. Jim

  43. I learned a lot about proper solid and acidity from your post and spent a hefty amount of time on your thoughts and solutions for Black Spot on roses. My aunt Gene and her mother both grew roses and were in a constant war with black spots. They used everything imaginable from pretreating with stem waxes to maniacal pruning to keep their roses in the winner’s circle at the county fair.

    • Thank you for comm bring Andy. It certainly is a constant battle to deal of with black spot in Roses. All the best. Jim

  44. Hello Jim, I must say that this article is very helpful and informative. Plant diseases are very common and it is very hard to secure plan today. I have a garden and nearly all of my flowers are affected by Mildews, I did not know that I should destroy all affected plants, thank you for sharing, there is still some I can save.

    • Hi Daniel. I’m sorry to hear about the mildew in your garden. Just check that you don’t have an overhead watering system , or that your plants are in to much shade. Jim

  45. I find a few of my plants getting some disease mainly visible on the leaves. I believe these are the Black Spots.  Iam going to try  the natural recipe to see if the situation changes.I have never thought it necessary to do a soil test to check the PH. I just add fertilizers and let it work out. Maybe that is the reason things do not work out that well.

    I am also just discovering something that I have never paid attention to. Checking the roots is something I have not looked into. I guess I always only look at the leaf.

    Thank you for taking your time to give us this post. Very useful.

    • Thank you Carol. I’m glad you learned something from my blog enjoy your garden. Jim

  46. great information grandpa’s green thumb. thanks a lot, your article would help improve my little backyard garden. 

    i have one question though. aside from manually checking out for a disease resistance in plants, so as not to purchase a sick plant, is there no kind of a digital apparatus specifically designed for that purpose?

    another one about mixing the soil to make it fertile. can you tell the quantity of lime and decomposts to mix into the soil?

    • Hi. There might be a device available to check for diseases however your own eyes will always be the best. Once you know what you’re looking for it actually becomes easy . The quantity of line you add will depend on the acidity of your soil. The lime or dolomite you purchase at a garden centre will tell you exactly how much you need to apply according to your readings. You can obtain these readings by purchasing a testing kit. Jim

  47. What an interesting and informative article, as one who spent some years in a garden centre, which of course included speaking about problems with plants to gardening clubs, found this refresher most useful.  Have had this garden for some twenty three years, and doing as you advised, regarding the soil, have a fairly healthy set up, as we both know it does work if you look after the soil.

    This article is ideal for those who are having problems or do not know what to do.

    Well done,


  48. Keeping your garden beautiful and tidy is needed but making sure your plants grow healthy is a must. I only have a small backyard garden for veggies but I am not an expert when it comes to serious gardening. I have learned a lot from this article and it got me into thinking that I should observe more our plants to make sure it’s not infected with diseases. I only have 4 pots of roses away from the veggies. I now know how to keep it away from being infected with diseases. I guess our climate really helped on making it grow but I have to give it more nutrients so it will propagate better. 

    I often wonder why some plants at home have different color spots – orange, yellow and sometimes black. I thought the leaves were just drying because of the very hot weather conditions. Right now, we are experiencing typhoon season that’s why my veggies get drown. Surviving plants doesn’t grow as it used to. 

    i am going to bookmark this in case I have to look up for something that will bother my flowers and veggies. You did not only help us to identify the plant diseases but also gave a solution on how to treat our plants. My succulents are my biggest problem now that it’s raining so hard. I had to temporarily move them inside the house so it won’t get wet. Thank you so much for the lengthy article that we can always keep as a reference.

    • Hi. Thank you for reading my blog and for your positive comments. All the best. Jim

  49. This topic is a must have and must read! As my wife is a gardener and has several plants, she is going through this all the time reading and trying to figure out what works what doesn’t as she for sure has a green thumb! She loves her plants and this is one for the saved books and she I know will be referring to this for help and tips! 

  50. I have a little garden where I have little beautiful plants growing to my perfect taste, and hearing about these plant diseases does look scary as I have seen few mildew on some of the flowers planted at garden which you indicated that it needs to be destroyed to avoid spreading, is there another option than destroying the plant Because I honestly like this plant. 

    • You can cut it back and sray with a fungicide such as Mancozeb and see how it goes. All the best Jim

  51. I am happy I have perused your article. Wanting to begin gardening however had no clue that plants could rust. I truly like the manner in which you share your experience about infections and conditions that transpired direct. You have composed everything truly well and I see splendidly. This manufactures trust in tolerating your suggestions. I truly appreciate.

  52. That blackspot truly has me concerned.  I believe I have that on my rose leaves, even though the roses are beautiful right now.  I have often gotten a couple of more blooms during this summer time in Colorado, but that disease could be threatening them. I’ve been watering the roses every day, and that may be the important clue as to why this is happening.  I will go to every other day,  as it is very dry in Colorado.  Thanks for the information!

    Bobby O.

    • Hi Bobby. Just make sure that when you water them you don’t spray on there leaves. Jim

  53. Hey Jim,

    It is nice to see your post after a long time. Your deep knowledge and passion are truly reflected in your post. I love it.

    This is the first year I built a keyhole raised bed garden on my backyard underneath a big tree. The canopy of the tree is not that dense and we were hoping we will have enough sunlight but we were wrong. We removed some branches to have good light. I don’t see diseases but I do not have much produce. May be cheap seeds. The plants look healthy but only a few beans, few okras, and a few tomatoes. The carrots are only 1 inch long. Hope it grows some more. This is our experimental garden.

    I will spray my rose plants using your recipes. The leaves have holes.

    Thank you so so much for this info. 

    • My pleasure. I’m glad you enjoyed my post. Sitting under that tree seems like the way to go. All the best. Jim

  54. first of all i must admit that by the time i commenced reading i thought i was back in an agriculture class, so this means for me a good feeling. I have some knowledge with reference to your article and from my end of the world we experience a lot of those issues with plant particularly in the summer time. You have definitely expounded on my knowledge i will most likely spread the word.

    • Thank you. I’m glad you enjoyed the article and that it was of some benefit to you. All the best. Jim

  55. I have a small garden and my plants started to show signs of Mildew, I was desperate until I came across this post from GRANDPA’S GREEN THUMB. I followed Jim’s advice to the letter and solved my problem. now this is my reference site for gardening. thanks again to Jim for sharing his knowledge.

  56. WOW!!! Excellent write-up and an eye opener for me. Fortunately I haven’t had any issues like these to manage the extent that my plants are concerned. I did in any case, neglect to water two recently planted ones and they passed on so I need to replant new ones and utilize a type of suggestion to wet them properly; at the root.
    Your article expressed that it’s turning into a world issue, for what reason is that? Likewise my space is restricted and I need to begin utilizing a few pots for a couple of vegetable plants. Is there anything extraordinary I have to focus on accomplishing something like this? Thank you for sharing this educative article.

    • Hi. Thank you for reading my article. I believe it’s becoming a world wide issue because plant health is deteriorating, soils are becoming depleted and global climate change is having a drastic affect. Jim

  57. Wow, this is all very helpful information. I’ve suspected a few things were going on in our home garden, but it’s very helpful to see the photos of the common plant diseases as well as the descriptions too! We have had more success in the past, but the trees are now covering so much of the yard that I think we need to thin out a few before we should expect different results. We do love the look of the trees, so we’ll have to figure out a way to keep some trees while still allowing sunlight in to the yard!

    • Thank you for reading my blog Ali. I hope you got some good information from it. Jim


  58. Thanks, Jim for this great post on the disease of plants. I love gardening and have pinned this to my garden board on Pinterest. I had problems with my tomatoes last year the leaves turned yellow and fell off and I had no idea what was the problem. I now know it was probably a disease. I didn’t look close enough I thought they were just overwatered.

    • It would be difficult to diagnose the problem of your Tomato’s without seeing them. Yellowing of leaves can be caused by lack of nitrogen, overwatering or underwatering or many other issues. Thanks for reading my blog Lynda. Jim

  59. I’ve been struggling to keep our tomato, jalapeno, and basil plants healthy throughout the summer here in the mountains around Lake Tahoe. After reading your article, I think our problem has most likely been infertile soil (we got it from the local plant nursery but aren’t really sure how healthy it was when it arrived). I’ve also started to notice a lot of the oldest leaves becoming very dried out and turning brown. Do you think I’m not watering them enough? Or they’re getting too much sunlight? 

    • Hi Tucker. It sounds like your plant us suffering heat stress and lack of water. If you’ve been having hot weather for some time then you may have an issue with foils that are repelling water. Jim

  60. I’ve had so many plant problems, and I can’t tell you how happy I am to have come across this article and your site.  I feel like I’m always guessing what the heck I’m doing wrong, and it’s really nice to have an actual list of possible problems and solutions.  Wow.  It’s like a light was shined on my home.  LOL!  I love plants so much – they brighten and decorate any room, but not when they are sick and dying.  It’s so frustrating to bring home a gorgeous plant only to watch it wither and die before my eyes.  Thank you so much for writing this article.  I am so excited!

    • Hi Brandie. I love your enthusiasm, thanks so much for your positive comments. Jim

  61. Wow, I didn’t realize there was so much to soil preparation before you even start to plant, even checking the ph levels. No wonder I am battling to grow anything.

    It was interesting to read about the different diseases and how to treat them. I never really thought that so much could go wrong with plants, as the worst problems we have had is a snail and worm infestation. I also learned something new today, never to plant a new rose where an old rose has died.

    • Hi Michel. Thank you for reading my article. I’m glad that you enjoyed it. Jim

  62. Hi Jim! Thank you for this very interesting article on common plant diseases. I will pass it on to my father, who is convinced to have green thumbs. His last experiment on plants is the use of a deodorant he is allergic to in order to kill moths from eating the plants he has on his balcony. Yes. You read me correctly. Don’t laugh. So, I am thankful. Take care. Anso

  63. Hi Jim! Thank you for this very interesting article on common plant diseases. I will pass it on to my father, who is convinced to have green thumbs. His last experiment on plants is the use of a deodorant he is allergic to in order to kill moths from eating the plants he has on his balcony. Yes. You read me correctly. Don’t laugh. So, I am thankful. Take care. Anso

    • Hi Anne. Let me know how you father goes with his experiment using the deodorant. It certainly sounds interesting. Jim

  64. Iam loving these articles.  It seems the secret is with good prep of the soil.  So we have soil in our back garden at the moment.  Do we need to get new soil?  Or do we treat it?  We have a dog also so we are weary of using liquids etc that could harm our dog?  Look forward to your reply.  Thanks

    • Hi Darren. You can simply build up your old soil by adding manures and fertilizer. The liquid manures I recommend are all dog friendly. Jim

  65. Thank you for such an excellent article on the most common plant diseases.  I really appreciate your natural solutions.  I hate to resort to chemical solutions but will when I have to.  You give very common sense instructions such as having healthy soil.  If your soil is healthy, your plants will more likely be healthy too and less disease prone.

    One thing that resonated with me is planting my veggies to closely and not allowing enough air flow.  This is so necessary and I’ve now broken myself of the habit and my plants have been much healther.  I add manure and wood ashes regularly to the soil as well as compost and worm castings.  My plants are now doing much better!

    • Hi . You sound like you definitely know what you’re doing. Wood as is a fantastic additive to any soil. Roes is particular thrive when you add it around the base of the plant. Thanks for reading . Jim

  66. Oh I love the name of your website, Grandpa’s green thumb! I do have black spot on my roses on occasion and  never realised that I should actually discard the leaves rather than add it to my compost, so a great lesson there for me. I will certainly go round and remove the leaves and also try you recipe with bicarb of soda to make a spray.

    We do also sometimes have issues with powdery mildew on our fruit trees, so not that easy to get rid of the tree, but will try the spray that you recommended.

    • Hi. Thanks for reading. My wife Noela walks around the roses everyday and removes any sick leaves. Its not an easy task but she loves it. l the best. Jim

  67. Hi, it’s me again, Gomer Magtibay. I got reminded by this blog post of yours which I read last month while looking for a solution of fungal problems among plants in Google. Thankfully, I have bookmarked the blog post that made returning here possible. I returned here for the recipe, for your improvised natural solution against Black Spot. We got this problem in our newly planted grapes, we suspect that they’re infested with Black Spot. Now, with this solution that you’ve suggested, we’ll see how it goes.

    • Thank you for returning Gomer. Let me know how successful the spray is on your grapes. All the best. Jim

  68. This is a very enlightening review. Am able to gain many new knowledge from this review. I love how container garden do flourish,so I decided to plant pumpkin vegetable. My vegetables were about to attain their maturity stage when it started bringing a yellow spot. The spot got multiplied on the leaves and drop off at the long run. From this review, am able to know the disease that attacked my vegetable and I have take note of the necessary preventive measure. 

    Plant disease is like a hell to a farmer or gardener because it will bring out low yield which I usually termed as labor lost.

    • Hi Stella. If my article has helped you to understand the diseases in your plants better, them I’m thrilled. Thanks Jim

  69. Hello

    Very good article

    In our garden we have a lot of plants, my wife has noticed that some of them are starting to turn yellow, we tried many methods to save some of them, so I decided to analyze the soil.

    The effect was that the soil did not have all the nutrients you need for the plant and I noticed that the irrigated water is harmful

    The solution I found was to buy special water filters for watering the plants and the whole garden

    Thank you for the suggestions.

    • Hi. Yes, even plants can be affected by bad water. What a good idea to buy a filter. Jim

  70. After reading your article detailing the myriad of diseases that can attack plants it seems that humid conditions are the biggest culprit. We live in a hot dry area and don’t experience these problems. 

    I’d love it if you gave some tips on how to grow vegetables like tomatoes and protect them from insects. Thst is our biggest worry in starting a vegetable garden. A few years ago we removed our lawns and water hungry plants and put in a drought resistant garden. We installed a drip watering system. The traditional sprinkler system used to direct water everywhere including on the leaves. Glad we got rid of that after reading what you wrote.

    Thanks for sharing some valuable tips to create a disease free beautiful garden.

    • Thank you Edwin. I will be writing a blog on vegetable growing soon. Those drip irrigation systems are definitely Worth having

      Not only do they save you water , they also can help to prevent disease. Jim

  71. Hi Jim,

    This is a great article about all the common plant diseases that might come to our garden someday. I think the problem in my garden is I seldom check the root, so I didn’t notice my plants are actually dying due to strangled root. Do you have related tips to let me know a good root should look like?

    I also see black spot & mildews in our garden, and my father used to spray water and hope the next day they will all disappear. But, with your post and solution, I might be able to save the lives of our favorite plants in the future.

    • Thank you Matt

      Hopefully I can include some pictures of what a clean root system should look like soon. Jim 

  72. Hi Jim, I’m really excited at the sight of this articl. I have learned alot from reading about these plant diseases, especially this black spot disease which is very common in the area I live. Also my wife have left town for some time now and have left the care of her garden to me. She left the garden in good health and have been away fo just a week, I added some fertilizer  (chemical)  to these plants and its seem to be killing the chlorine in it and turning it yellow. What do I do? 

    • Hi Dane I would suggest you give the garden a good watering and then add a few wheelbarrows if a good compost around the plants. Jim

  73. What a great article to read to learn more about plants.

    As I was reading your article I was happy to see some things I can do now to help my plants and my garden to be in its best shape always.

    I have had many times of the different plant problems you talk about on the article, but I had no idea on what to do. 

    I will bookmark your article as I’m sure I’ll need to read it again sometime.

    This Summer we had a problem in the garden with some small bugs, we haven’t seen those bugs before, but a couple of years we saw one or two, this Summer some plants really had bad times with them.

    We couldn’t have any raspberries as these bugs destroyed the plants. 🙁  I’ll check more articles on your website to see if you have some information about these bugs, I don’t know the name, sorry. 

    • Hi Alejandra. Maybe you could send me more information about the bugs on the contact me page. I could give you an email address to send a photo to. Jim

  74. Thank you for sharing all your knowledge about plants. I did not know that plants could get something like rust. I have definitely seen mildew on leaves just like the one you showed in the picture.

    I will have to look out for root rot at my indoor plants because I don’t know if the drainage on those is okay. Can you still eat food from plants with these diseases if it looks okay?

    • Hi Edward. Thanks for reading my article. I wouldn’t eat food from sick plants. The fruit or vegetable could be contaminated. Jim

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