The hot and humid days of July and August are prime time for fungal infections to start popping up on your trees, vegetables, and landscaping plants. Some of the most common infections are powdery mildew, rust, leaf spot, and blight. Preventative treatments, and acting quickly to treat fungal infections when you first notice them are crucial to keeping your plants healthy and prevent annually recurring infections in trees and perennials. Luckily, myriad organic products exist to prevent and treat fungal infections. We know that the options can sometimes be confusing or seem overwhelming, so here’s a helpful primer:
Sulfur Fungicide
Products include: Bonide Sulfur Plant Fungicide, Safer Garden Fungicide
Sulfur comes in either a powder or a concentrated liquid. It works better as a preventative than a treatment or cure. This is because the sulfur prevents fungal spores from germinating. It can be effective in slowing down an infection by keeping the fungus from multiplying rapidly, but it won’t have much of an impact on existing infections. It is most effective when applied at the beginning of the season, and on a regular basis before you notice signs of a fungal disease. Sulfur should never be applied within 4-6 weeks of using an oil spray. It will have a phytotoxic reaction with the oil, and result in plant death. Some plants are especially sensitive to sulfur products, so definitely avoid using it on gooseberries, apricots, raspberries, currants, and anything in the cucurbit family (cucumbers, squash, melons). It’s also important to consider that with continued application, sulfur can lower the pH of the soil and start to affect plant health.
Copper Fungicide
Products include: Bonide Copper Fungicide
Copper is a good choice of fungicide because it essentially kills the fungus. It is very successful for treating and preventing tomato blight and can be applied once a week. It’s important to follow the dilution instructions very carefully, since too strong a mixture can burn leaves. Young plants, and new growth are often very sensitive to copper, so applying an extra diluted mix is a good idea. It’s also important to apply copper during cooler times of the day when the sun is not too bright, so evening applications are preferred. Azaleas and Rhododendron are sensitive to copper. With long term use, copper can accumulate in the soil and eventually make it to streams as runoff. Large accumulations of copper can reduce the diversity of naturally occurring plant life. It’s unlikely that home gardeners will contribute to this problem, but it is a factor to consider.
Oil Based Fungicide
Products include: Organocide, Neem, PureSpray Green, Monterey Horticultural Oil
Neem oil is going to be the most effective oil for controlling fungal infections. It is a good choice for mild to moderate powdery mildew infections, but doesn’t do much good for blight, leaf spot, or rust. Oils are mostly used to control insects, but since many fungal infections are spread by insects, keeping pests at bay is a good practice for maintaining plant health.
Bacterial Fungicide
Products include: Serenade, Actinovate
Bacterial fungicides, also called biofungicides are an exciting new development! They contain bacteria and other microbes as the active ingredient and work in a variety of ways. Some bacteria actually prey on and consume the fungus infecting the plant, some trigger a defensive response in the plant that helps it prevent the fungus from further invasion, and some bacteria produce a toxin or antibiotic that acts against the fungus. Biofungicides work best as a preventative spray, but an application after disease is noticed can be very effective at preventing the spread of the pathogen. Unfortunately, spraying a biofungicide after you notice an infection will not likely cure the plant of the disease, except in the case of mild to moderate powdery mildew infections. Since these sprays contain living organisms, it’s important to store them at a constant temperature. Room temperature is usually fine, but leaving them outside or in a shed or garage where temperatures fluctuate daily and seasonally, can reduce the number of live microbes and decrease the efficacy.
Potassium Bicarbonate
Products include: GreenCure
Potassium bicarbonate is safer for the environment, and less harsh on plants than some of the other fungicides like copper and sulfur, so it is a good choice for sensitive plants. It works by killing the mature fungus as well as the spores, so future infections are less likely. With prolonged use, potassium bicarbonate can raise the pH of soil, so testing the pH regularly is recommended.
Terry says
I just noticed what appears to be blight on some of my tomato plants. I’ll come in to the store tomorrow for some copper fungicide. I also noticed some blossom end rot in some tomatoes. Any suggestions? I have some lime with calcium but I already applied it when I planted? Thanks for posting.
ashley says
Hi Terry, Calcium and magnesium deficiencies can cause blossom end rot. Fortunately there are a lot of cal-mag products to feed your tomatoes with.
Madalyn says
Hey Terry,
Ashley’s right about calcium and magnesium, and a lot of times tomatoes need more than what is available in the lime applied at the beginning of the season. I’d recommend bone meal (also very high in phosphorus), crab shell, or a liquid cal-mag supplement. Luckily once you start adding calcium, the problem is resolved very quickly!
Jan Johnson says
I use Neem, Bt and Serenade for bug and disease control. Since Neem comtrols some baterial disease will it also kill the bateria in Serenade and Bt products if used together? The products are a little costly and I don’t want to waste time and money.
Jeff says
As I understand it, copper is a preventative, and potassium bicarbonate kills fungi but doesn’t prevent re-infection. Can they be mixed to both kill and prevent?
Prof. B. Bhattacharya says
I have an apple plant in my balcony. The climate in Kolkata is humid and hot. Leafs have converted to black. I applied Cu base fungicide three times with gap of five days. The condition has not improved. Please advice.
Prof. B. Bhattacharya says
Some corrections. Read all the leaf are gradually blackening. Blackening starting from leaf tips. Can I use ice in soil to cool down soil temperature.
ashley says
We believe the plant has what sounds like an over watering issue. Make sure there is plenty of drainage in the pot and the plant is in full sun. If it is a fungal issue we would suggest a sulphur based organic spray. Ice cubes will have no effect on cooling the tree down. If it is too hot there for apples, you might try another, more heat-tolerant tree.
Jo Ogbajie says
Hi everyone. I noticed yellowing of my cucumber plants last week. don’t know the kind of infections on the cucumbers. I need help on the best form of treatment. The cucumbers are fruiting now.
ashley says
Hi Jo, Yellowing could be caused by many different problems – pests, diseases, nutrient deficiencies, to name a few. Check your plants on the top and underside of leaves for pests and caterpillars, to either identify, or eliminate that possible cause. Downy mildew can cause yellowing – remove affected leaves and dispose of them. Cut back some foliage on the vines to let air circulate more freely. Good luck!
Melanie says
Hi…my daughter (14) received a cherry tomato plant for X-mas, and takes its care of living healthily, serious (and personal). The care instructions on the little label attached said, “Do not transplant. 6 hours of sunlight daily & water 1 in. wkly.” Every morning she puts it out in the sunlight, (highs avg. 70-75) in CA, and brings it in before the temps begin to cool. Unfortunately, (small) white fuzzy spots surfaced on the leaves, and the tomato’s remain green showing no signs of ripening, or growth. Which treatment and further care will have the best outcome? Thanks
Bernard says
I am into herbs so is it advisable to use any of these products above
Susan McIntyre says
Hello,
This common but overlooked airborne pathogen is known to cause diseases of unknown cause. Some online documents state this cancer-causing, mental illness-inducing microorganism is not zoonotic. That’s wrong! It’s carried and shed by bats in their feces. And healthy people can get it, too.
My coworkers and I, all immunocompetent, got Disseminated Histoplasmosis from roosting bats, that shed the fungus in their feces. The doctors said we couldn’t possibly have it, since we all had intact immune systems. The doctors were wrong.
More than 100 outbreaks have occurred in the U.S. since 1938, and those are just the ones that were figured out, since people go to different doctors. One outbreak was over 100,000 victims in Indianapolis. 80-90+% of people in some areas have been infected, and it can lay dormant for up to 40 years in the lungs and/or adrenals.
This underdiagnosed airborne infectious disease mimics the flu and can cause malignancies, precancerous conditions, rheumatological diseases, connective tissue diseases, heart disease, autoimmune symptoms, inflammation, adrenal insufficiency, seizures, migraines, hydrocephalus, hallucinations, etc. and is often undiagnosed/misdiagnosed in immunocompetent people.
It’s known to cause hematological malignancies, and doctors claim leukemia patients go into remission when given antifungal. My friend in another state who died from lupus lived across the street from a bat colony. An acquaintance with alopecia universalis and whose mother had degenerative brain disorder has bat houses on their property.
Researchers claim the subacute type is more common than believed. It’s known to at least “mimic” autoimmune diseases and cancer and known to give false-positives in PET scans. But no one diagnosed with an autoimmune disease or cancer is screened for it. In fact, at least one NIH paper states explicitly that all patients diagnosed with sarcoidosis be tested for it, but most, if not all, are not. Other doctors are claiming sarcoidosis IS disseminated histoplasmosis.
What if this infection, that made me and my coworkers so ill, isn’t rare in immunocompetent people? What if just the diagnosis is rare, since most doctors ignore it?
Older documents state people who spend a lot of time in a building with roosting bats, in caves, working as landscapers, construction workers, pest control workers, etc. are known to get Disseminated Histoplasmosis, but the info appears to have been lost, for the most part. And now bat conservationists encourage people to leave bats in buildings/homes. What a terrible mistake they’ve made.
This pathogen parasitizes the reticuloendothelial system/invades macrophages, can infect and affect the lymphatic system and all tissues/organs, causes inflammation, granulomas, and idiopathic (unknown cause) diseases and conditions, including hematological malignancies, autoimmune symptoms, myelitis, myositis, vasculitis, panniculitis, dysplasia, hyperplasia, etc. It causes hypervascularization, calcifications, sclerosis, fibrosis, necrosis, eosinophilia, leukopenia, anemia, neutrophilia, pancytopenia, thrombocytopenia, hypoglycemia, cysts, abscesses, polyps, stenosis, perforations, GI problems, hepatitis, focal neurologic deficits, etc.
Many diseases it might cause are comorbid with other diseases it might cause, for example depression/anxiety/MS linked to Crohn’s.
The fungus is an Oxygenale and therefore consumes collagen. It’s known to cause connective tissue diseases (Myxomatous degeneration?), rheumatological conditions, seizures, and mental illness. Fungal hyphae carry an electrical charge and align under a current. It causes RNA/DNA damage. It’s known to cause delusions, wild mood swings (pseudobulbar affect?), and hallucinations. It’s most potent in female lactating bats, because the fungus likes sugar (lactose) and nitrogen (amino acids, protein, neurotransmitters?), releasing lactase and proteinases to obtain them. What about female lactating humans…postpartum psychosis (and don’t some of these poor women also have trouble swallowing)? The bats give birth late spring/summer, and I noticed suicide rates spike in late spring/early summer. It’s known to cause retinal detachment, and retinal detachments are known to peak around June-July/in hot weather. A map of mental distress and some diseases appear to almost perfectly overlay a map of Histoplasmosis. Johns Hopkins linked autism to an immune response in the womb. Alzheimer’s was linked to hypoglycemia, which can be caused by chronic CNS histoplasmosis. Cancer is known to occur more often near rivers than in mountains or deserts, just like this infection.
The bats eat moths, which are attracted to blue and white city lights that simulate the moon the moths use to navigate. Bats feed up to 500 feet in the air and six miles away in any direction from their roost, but not when it’s raining or when the temperature is less than approximately 56° F. The fungus can grow in bird feces, but birds don’t carry it because their body temperature is too high, killing the fungus.
I believe the “side effects” of Haldol (leukopenia and MS symptoms) might not always be side effects but just more symptoms of Disseminated Histoplasmosis, since it causes leukopenia and MS symptoms. What about the unknown reason why beta receptor blockers cause tardive dyskinesia? The tinnitus, photophobia, psychosis “caused” by Cipro? Hypersexuality and leukemia “caused” by Abilify? Humira linked to lymphoma, leukemia and melanoma in children? Disseminated Histoplasmosis is known to cause enteropathy, so could some people thought to have nonsteroidal anti-inflammatory drug enteropathy have it and taking NSAIDs for the pain/inflammation it causes, and the NSAIDs aren’t the actual culprit?
From my experience, I learned that NO doctor, at least in DFW, will suspect subacute and/or progressive disseminated histoplasmosis in immunocompetent people. Some doctors, at least the ones I went to, will actually REFUSE to test for it, even when told someone and their coworkers have all the symptoms and spend a lot of time in a building with bats in the ceiling. Victims will be accused of hypochondriasis. (My doctors told me only farmer’s get it, it’s only in bird feces, and it only infects the lungs…wrong, wrong, and wrong!) In fact, the first doctor to diagnose me was a pulmonologist, and the only reason he examined me was to try to prove that I didn’t have it, when I really did. No doctor I went to realized bats carry the fungus. And NO doctor I went to in DFW, even infectious disease “experts,” understand the DISSEMINATED form, just the pulmonary form, and the only test that will be done by many doctors before they diagnose people as NOT having it is an X-ray, even though at least 40-70% of victims will have NO sign of it on a lung X-ray. It OFTEN gives false-negatives in lab tests (some people are correctly diagnosed only during an autopsy after obtaining negative test results) and cultures may not show growth until after 6-12 weeks of incubation (but some labs report results after 2 weeks).
One disease of unknown cause that could be caused by Disseminated Histoplasmosis: I suspect, based on my and my coworker’s symptoms (during our “rare” infectious disease outbreak) and my research, that interstitial cystitis and its comorbid conditions can be caused by disseminated histoplasmosis, which causes inflammation throughout the body, causes “autoimmune” symptoms, and is not as rare as believed. I read that “interstitial cystitis (IC) is a chronic inflammatory condition of the submucosal and muscular layers of the bladder, and the cause is currently unknown. Some people with IC have been diagnosed with other conditions such as irritable bowel syndrome (IBS), fibromyalgia, chronic fatigue syndrome, allergies, and Sjogren’s syndrome, which raises the possibility that interstitial cystitis may be caused by mechanisms that cause these other conditions. In addition, men with IC are frequently diagnosed as having chronic nonbacterial prostatitis, and there is an extensive overlap of symptoms and treatment between the two conditions, leading researchers to posit that the conditions may share the same etiology and pathology.” Sounds like Disseminated Histoplasmosis, doesn’t it?
My coworkers and I were always most ill around April/May/June, presumably since the Mexican Free-tail bats gave birth in Texas during May (and the fungus was most potent), and fall/Thanksgiving to December, for some unknown reason (maybe migrating bats from the north?). We had GI problems, liver problems, weird rashes (erythema nodosum, erythema multiforme, erythema marginatum/annulare, etc.), plantar fasciitis, etc., and I had swollen lymph nodes, hives, lesions, abdominal aura, and started getting migraines and plantar fasciitis in the building, and I haven’t had them since I left. It gave me temporary fecal incontinence, seizures, dark blood from my intestines, tinnitus, nystagmus, blurry vision/floaters/flashes of light, benign paroxysmal positional vertigo, isolated diastolic hypertension, what felt like burning skin, various aches and pains (some felt like pin pricks and pinches), tingling, tremors, “explosions” like fireworks in my head while sleeping, and temporary blindness. Suddenly I was allergic to Comice pears (latex fruit allergy or oral allergy syndrome?). I had insomnia (presumably from the fungus acidifying the blood, releasing adrenaline) and parasomnias. It felt like strong bursts of electrical shocks or steady electrical currents in my body, which now feel like low electrical currents at times, mostly at night. I suddenly had symptoms of several inflammatory/autoimmune diseases, including Fibromyalgia, Sarcoidosis, ALS, MS, Sjogren’s syndrome, etc. that have disappeared since leaving the area and taking nothing but Itraconazole antifungal.
No one, including doctors (we all went to different ones), could figure out what was wrong with us, and I was being killed by my doctor, who mistakenly refused to believe I had it and gave me progressively higher and higher doses of Prednisone (2 years after I already had Disseminated Histoplasmosis) after a positive ANA titer, until I miraculously remembered that a visiting man once told my elementary school class that bats CARRY histoplasmosis. So much of it that they evolved to deal with the photophobia and tinnitus it causes by hunting at night by echolocation. There’s a lot more. I wrote a book about my experience with Disseminated Histoplasmosis called “Batsh#t Crazy,” because bats shed the fungus in their feces and it causes delusions and hallucinations, I suspect by the sclerotia fungal mycelia can form emitting hallucinogens (like psilocybin and dimethyltryptamine) along with inflammation in the CNS. (Schizophrenics have 2X of a chemical associated with yeast, part of the fungal life cycle.)
Thank you for your time,
Susan McIntyre
P.S. Doesn’t this infection share all the same symptoms with Gulf War Syndrome?
Pamela Campbell says
I’m a beginner vegetable gardner and have been researching about my tomato plant now having wilting and yellow leaves, but it just occurred at this month and the plants have been healthy until just a few weeks ago. In my research, it seems as though my tomato plants have “Verticillium wilt fungal disease” that lives in the soil. Apparently, I need a low-nitrogen, high-phosphorus fertilizer to help the existing disease plant, though I understand it will not cure the disease. I did prune off dead and dying branches, but I’m losing a lot of tomato’s. What is the best product to help treat the plant from this disease? Is there anything I can do to the soil to help prevent the disease for next year’s crop? I would appreciate a reply to help me with this problem. Thank you. Pamela Campbell pcampbell22@att.net;
ashley says
Hi Pamela,
Before we give you any advice, we have a question for you: is the yellowing happening all over the plants, or is happening more at the bottom of the plants?
ashley says
Hi Again, Pamela, I wanted to give you some general advice on trying to avoid various soil-borne pathogens on your tomato plants for next year’s garden. First off, rotate your plantings so that tomatoes are not planted in the same spot next year, so any left-over spores from this year won’t be where your tomatoes are next year. Allow plants 3′ spacing and pluck off suckers as the plant grows to allow good air flow. Prune off bottom leaves/branches that get close to soil so that dirt won’t splash up onto your plants. Mulch with ground-up hardwood or straw. Lastly, try to select disease-resistant varieties, if you can. These practices won’t eliminate blight and wilt, but they will keep them at bay, and hopefully keep you rolling in tomatoes!
jean sander says
I used copper sulfate on the fungus (identified by my co-op extension in Ct.,) on my carpinus betulus hedge. That was the product that the co-op suggested. I started spraying as the leaves began to bud-out and then every 10 days until the leaves were fully developed. No results!!! The hedge is planted in full sun.albeit some are in partial shade. Each shrub is infested with the fungus and I don’t know what to do for next year. By the way, the shrubs have been in the ground for only 3 years…I also remove every diseased leaf at the end of the season.
Please HELP!!!
ashley says
Ugh – how awful. Copper would have been what we recommended as well to treat an already-existing fungal problem. Another good option to try is a potassium bicarbonate-based fungicide (such as GreenCure, which kills both mature fungal infections and spores. For next year, we would recommend early and regular application of sulphur, which prevents spores from developing, hopefully stopping the fungus early.
Unfortunately, if the infection is really advanced, and seems to be coming back annually, even with removing diseased leaves, you may have to remove the plants and start over.
Robert Rouse says
I have a palm tree which looks quite poorly. The new fronds are brown and dry. I have been advised that the likely cause is a fungus. Are you able to advise a treatment please?
ashley says
We would recommend a copper-based fungicide for an already existing fungal infection. You could also try treating with a potassium bicarbonate-fungicide that kills both mature infections and attacks spores. Good luck!
Emory says
My zinnias,bell peppers and tomato plants are severely infected with a leaf spot. The spots appear to be brown with a yellow halo around them. Soon after they get the spots the leaves turn yellow and drop off or wither up.
Is there a chemical way to treat my soul for prevention for next year ?
(I have tried Dacosil and neem oil/baking soda. Does not appear either had slowed down the issue)thanks
ashley says
Hi Emory,
Here are a few things you can try to improve your situation for next year. The first options involve heating the soil to temps that will kill the fungus.
1. If you are planting in a small area or pots, you can sterilize the soil for next year by putting the top 2-3 inches of soil in baking pans and baking them in a 180-degree oven for 30 minutes to kill all fungus.
2. For larger areas, remove all plants and dispose of them so that the fungal spores on the plants can’t get back into your soil. Then water the soil until it is saturated – this moisture will help create a steamy environment that most fungi can’t tolerate. Then cover the soil with 2 layers of thick plastic sheeting and secure it with landscape staples or pegs so that you have a secure covering that will not let heat escape. Let the sun shine on the plastic for about six weeks – this will raise your soil temps high enough to kill most pathogens. This process works best when it is hotter and sunnier outside. Next planting season, amend your soil with earthworm castings to help repopulate good microbes in your soil.
3. Next year make sure to rotate your crops so the same types of plants aren’t planted in the same place they were this year. Apply sulfur-based fungicide to your plants at the beginning of the growing season BEFORE you see signs of fungal infections – sulfur works as a preventative, preventing spores from developing. If you do see infection, try a copper-based fungicide at the first sign of problems.
So sorry you are struggling with this issue!
TransAgro says
Thanks for sharing all of your experiences!
Natalie Daughtry says
Hi, I have a gardenia Bush that I have been battling rust on since it was planted 4 years ago. I have been using neem oil which gets rid of it as long as you apply it often. I am going to try the potassium bicarbonate to see if I can cure it. My other issue is that the plant will not grow. It is almost the same size as the day I planted it. Any suggestions would be appreciated. This plant is very special to me. It was given to me when my dad passed.
ashley says
Hi Natalie, It sounds like you may have some deficiencies in your soil if the gardenia has not grown at all. I would get a soil test kit from your county extension agent (you can search online for your local county government agricultural extension) and send it in to see if your soil’s pH is either very low or very high, or if major nutrients are absent. These tests are usually free or a minimal cost. You also may have a dwarf gardenia variety, in which case it will stay small, but should still flower.
jo says
Hi, can I get the remedy, for Xanthomonus and Collitotrichum infections in palm trees, without using chemical compositions. Can I use Bordeaux in hot summer, when its around 35 degree C to the flowers in palm varieties.
Harvey Feldman says
This is all very confusing. If my peach and nectarine fruit trees show peach tree leaf curl with raised blisters what is the best product to use to stop the spread of the disease or even kill off the disease on the leaves infected or should the infected leaves be removed from the young trees, now about 6 or 7 feet high now. From the comments above sulfur like bonide fruit and nut tree spray which is sulfur based seems to be a preventative before the disease and copper may not kill the disease. What would be the best product to use to kill the spores etc or should alternate spraying of a copper based and sulfur based product like bonide be used? Help please.
ashley says
Copper fungicide is better at killing existing fungus and sulfur is good for preventing spread, so sulfur is better to apply at the first sign of fungal issues. We’d recommend cutting away as much infected material as you can and then applying a copper fungicide to kill what’s left. Please follow all directions when using copper fungicide because misapplication can damage plants. Hopefully you can get the problem under control this year, and then next year, use sulfur at the start of the season for prevention, and copper if necessary later on.
Murungi Jonan says
How can I prepare a bone meal easily to combat fungal infections easily
Thanks for spearheading organic techniques and minding more about environment
Aim higher, Good luck!
ashley says
Hi! We don’t recommend bone meal for combatting fungus. It is generally used for fertilizing plants. We would recommend one of the treatments listed in the blog post if you have a fungus issue on your plants. Cheers!
ken johnson says
Ashley – many thanks for your informative replies to so many queries. I’d like to know: do Neem oil in emulsion and potassium bicarbonate work well together to control Camelia leaf blight?
ashley says
Hi Ken, Since both Neem and potassium bicarb work well as fungicides, I would think they would help out with blight on camellias. You should spray them at the end of the day, and try to avoid the flowers so you don’t interfere with pollinators.
alexis soule says
serenade and greencure appear to be no longer in production
Eric says
What is the best Chestnut Tree blight fungi cure? I’m thinking of growing a Chestnut tree or more. I read blight wiped out half a billion chestnut trees in the 1800’s. What do recommend?
ashley says
Hi Eric, Yes, American Chestnut trees were just about wiped out from Chestnut Blight brought in on Chinese Chestnut trees back in the 19th century. As far as recommending fungicide, we would advise you to contact your local county agricultural extension agent to recommend both which trees to plant and which treatments to use in your specific area. You may already know this, so forgive me if I’m repeating stuff you’ve heard, but your state agricultural agency is a public service that helps gardeners and farmers be successful in planting and growing in your specific area. You can search online for “Agricultural Extension Agent (insert your county/state here)” and find their contact info. Their job is to help folks just like you with questions just like yours for your particular growing region. I think they would be able to give you the best, most reliable info. Good luck in working to repopulate the Native American Chestnut Tree! PS, did you read the novel “The Overstory”? American Chestnuts are featured prominently in it! — Ashley at Fifth Season Gardening
Erovie A Anthony. says
Thank you so much. But where can I buy the chemicals you mentioned in Nigeria?