Organic fungicides: limestone, pyrethrin, potassium bicarbonate

strawchicago(zone 5a)September 12, 2013

My last house, 1/2 hour away was acidic clay ... major black spots despite spraying. I was discouraged and gave up on roses. My present house, alkaline clay with limestone, pH 7.7, fertilized with alkaline horse manure (had lime), and chicken manure.

No black spots for the last 2 years with my 55 roses, until this year's experiments with cocoa mulch (pH 5.6 to 5.8), plus stable stops liming and switched to wet & acidic bedding. Roses mulched with acidic cocoa mulch are 10% infected with BS, and the 7 roses mulched with new horse manure are 30% infected. The rest of roses NOT mulched, just alkaline limestone clay, are still clean. Also no chicken manure this year.

Two sites documented high copper, zinc, and boron in chicken manure. Those elements are added to chicken feed, Here's a quote from link below "Their feed manufacturers know, that Copper and Zinc added to the feed ration increases growth, and that Boron is essential for the utilization of Calcium." Copper is a fungicide.

Here's a recipe for homemade fungicide: "�Bordeaux mixture for use during the dormant season can control some fungal and bacterial diseases. You can make your own Bordeaux mix with ground limestone and powdered copper sulfate. Mix 4 parts of each with 50 gallons of water."

Below is Mirandy Hybrid Tea in my limestone clay, fertilized with chicken manure ... picture taken last fall:

Here is a link that might be useful: Why chicken manure stimulate plants' growth?

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strawchicago(zone 5a)

Potassium bicarbonate, or "Green Cure", is 25% to 35% more effective than baking soda. "Green cure" is safe to spray on leaves. One guy in Colorado (dry climate) recommended "Green Cure" for mildew in HMF.

Blendguy (Robert) who started the English Roses Forum, stated in this forum on Oct 5, '07: "I've been using it this year, and I've had very good luck in my garden ... I bought Greencure because I had heard so many horror stories of trying to grow "old" and "English" roses so close to the ocean (I've about 35).

I've had very good success with it warding off and/or eliminating PM. I've had a very little PM, but nothing compared to my neighbors ... all seem to have PM everywhere in their gardens ... I've "heard" that the remedies for PM, like Greencure, might very well be less successful on BS. " Robert.

Both potassium and calcium is needed for the integrity of cell membrane, to prevent fungal invasion. Folks report success spraying with diluted milk. Milk has calcium, plus salt. Salt also inhibits fungal growth.

I prefer limestone as fungicide, since it's lowest in salt. My clay is dolomitic-limestone clay, high in magnesium. Dolomitic Limestone provides 25% calcium and 10% magnesium, salt index 0.8.

Calcitic limestone provides 36% calcium when the rain water (pH 5.6) breaks it down, low salt index 4.7.

Gypsum provides 22% calcium, 17% sulfur, with salt index of 8.1, used to de-salt sodic soil, also to neutralize bicarbonates in alkaline tap water.

Lime sulfur was used in the old days as a fungicide, pH over 11.5, very caustic. Lime sulfur is made by reacting calcium hydroxide with sulfur.

According to eHow: "Potassium bicarbonate is soluble in water. "Green Cure" is potassium bicarbonate, effective against mildew. Below is Wise Portia rose, prone to mildew, I gave it sulfate of potash NPK 0-0-50 and gypsum (calcium sulfate) for fungal-prevention.

Here is a link that might be useful: Green cure (potassium bicarbonate) and mildew

    Bookmark   September 12, 2013 at 10:21AM
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strawchicago(zone 5a)

Here's an excerpt on pyrethrin: "Pyrethrin leaves that come from the painted daisy flower are widely used in commercial fungicide for plants. Grow your own painted daisies and use the flowers as fungicide for plants. Dry the flower heads, then grind them or soak overnight in 1/8 cup of alcohol. Mix with up to 4 gallons of water and strain through cheesecloth."

Niels in Denmark, a former M.D., now a horticulture specialist and rose grower, wrote on pyrethrin in English Roses forum: "I use an organic insecticide - natural pyretrum extract - approved for organic food production - since it is not toxic to humams - and are degraded by uv-light - but the extract is in rapsseed oil and it says on the small bottle to use 20 drops pr. 1 litre of water - I know that spraying in this sunny weather conditons with it can cause som leafburn- spots on some roses leaves and I need to wait to use until the temps and the sun is less intense -

I wrote about natural pyrethrum on my blog - Natural pyrethrum - smells really nice - like spicy chrysanthemum leaves and it keeps aphids totally at bay on my roses - I wrote about this organic solution my blog a few years ago - I highly recommend natural pyrethrum - and I have pictures to show how effective it is:

I think I have about 20 cultivars out of 150 I grow - that needs some spraying ... I can keep my rosesbushes very clean. Some roses like the bourbons Reine Victoria and Louise odier - are very, very blackspot prone - I always get compliments from other gardeners that they have never seen these cultivars as clean as in my garden." Niels.

**** From Strawberryhill: below is my hedge of Austin roses: Christopher Marlow, Pat Austin, Lilian Autin, Queen of Sweden in my limestone clay. They are clean if fertilized with alkaline horse manure (with lime), and chicken manure (high in boron, copper, and zinc).

Here is a link that might be useful: How to make your own organic fungicides

    Bookmark   September 12, 2013 at 10:36AM
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strawchicago(zone 5a)

Artillery fungus, is defined by Penn State as: "The artillery fungus is a white-rotting, wood-decay fungus that likes to live on moist landscape mulch. It is in the genus Sphaerobolus (Greek for âÂÂsphere throwerâÂÂ) and is very common across the USA, especially in the East,

The artillery fungus actively (uses energy) shoots its spore masses, sort of like a cannon or howitzer (an artillery piece). We will call these âÂÂspores,â although they are technically spore masses, or gleba. The spores are usually shot only a short distance but the wind can carry them for longer distances and even up to the second story of a house." See link on fungus on decayed mulch:

**** From Strawberryhill: I got black spots on my white sidings and wood trim where I mulched with decayed bark. So I switched to horse manure with recycled wood (with mold retardant), and lime. But the horse manure changed this year, so I use zero mulch.

Here's a quote from the below link: "Rake and remove fallen leaves of infected plants. ⢠Apply a fresh layer of mulch to garden beds at the beginning of the growing season."

The old garden roses: Comte de Chambord, Duchess de Rohan, and Paul Neyron are very clean once planted in my alkaline clay. My Comte de Chambord rose was a black spot mess when it was in a pH 6.5 potting soil, topped with alfalfa meal (slightly acidic and naturally high in sugar, which promotes fungal growth).

Below is Duchess de Rohan rose, pure heaven-scent, the scent is addictive and strongest among the hundreds of roses I sniffed both in my garden, and at the rose parks. Outer petal got eaten by Japanese Beetle.

Here is a link that might be useful: Effective fungicides

This post was edited by Strawberryhill on Thu, Sep 12, 13 at 11:17

    Bookmark   September 12, 2013 at 11:15AM
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strawchicago(zone 5a)

Found a link on Bordeaux mixture sold commercially to control fungal diseases. The homemade stuff is "to prepare a gallon amount of a 4-4-50 Bordeaux Mixture spray, measure out 6 ý teaspoons of copper sulfate and 3 tablespoons of hydrated lime."

More excerpt on Bordeaux Mixture: "For peaches, use the material as a dormant spray for peach leaf curl, on apples and pears to help with control of fire blight, on grapes for black rot control, and on roses for black spot and other fungus disease control."

*** from straw: We have dolomitic/limestone clay, fungal diseases is not a problem here. Neither I nor my neighbors need to spray our peach trees.

I use chicken manure around my fruit trees (pear, cherry, and peach), way-more fruits than 10-10-10 chemical fertilizer. Chicken manure is high in copper, boron, and zinc ...less available in my alkaline clay.

Below is my neighbor's hybrid tea rose, very clean, mulched with limestone, picture taken in humid weather this month. She doesn't spray, but uses soluble fertilizer.

Here is a link that might be useful: Mississipi State on Bordeaux fungicide

This post was edited by Strawberryhill on Thu, Oct 17, 13 at 12:22

    Bookmark   September 19, 2013 at 12:43PM
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strawchicago(zone 5a)

Found another pdf file by Purdue University Extension on effectiveness of Bordeaux against both bacterial and fungal infestation: powdery mildew, bacterial leaf spot, fire blight, downy mildew, anthracnose pathogens. It adheres to leaf, and resists spring rains. Lime & copper sulfate (Bordeaux) has been used for 150 years.

Here is a link that might be useful: Purdue University - Using Organic fungicides

    Bookmark   September 19, 2013 at 3:28PM
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strawchicago(zone 5a)

I was googling "Healthy roses" and found this blog by Raft Island Roses Owner Frank Gatto with pics. of the most healthy roses! Here's a summary of his tips, most appropriate for acidic soil, PNW area:

"Five gallons per week per rose" is Gatto's advice. "Water deeply," he stresses. "When you pour on five gallons and it soaks down deep, your roses grow roots to reach that water."

For planting, Gatto mixes 50 percent native soil and 50 percent organic compost or good potting soil and adds a cup each of bone meal and soil sweetener per bush. He also gives established plants a cup of lime in March, for optimal soil pH, which allows plants to make better use of food."

Gatto advises giving roses small but frequent meals, as opposed to large amounts of fertilizer less often. He uses a balanced granular fertilizer with an N-P-K number no higher than 20 (such as 15-15-15), along with a blend of organic meals including alfalfa, cotton seed, fish, blood and kelp. "I give each one a handful (about a half a cup) every three weeks."

**** From Straw: Nurseryman Gatto lives in PNW, most likely acidic soil, which benefits from adding one cup of lime per planting hole (same as Roses Unlimited's instruction in SC). My soil is alkaline, so I add one cup of gypsum per planting hole to break up my clay (gypsum has 17% sulfur).

There's logic in Gatto's spreading one cup of lime in March. Keep surface dry and alkaline is the key to fungal prevention. I spread alkaline manure in spring time, or do late-fall mulching with alkaline manure ... I don't have BS in spring nor summer, and very minor in late fall.

Here is a link that might be useful: Raft Island Rose Nursery's tips for healthy roses

This post was edited by Strawberryhill on Thu, Oct 17, 13 at 15:24

    Bookmark   October 17, 2013 at 12:28PM
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strawchicago(zone 5a)

Here's an excerpt on bone meal in alkaline soil:

"In New Mexico, bone meal is not the gardener's best source of phosphorus. In most New Mexico soils, the phosphorus is not available to the plants. Our calcareous soils with their high pH keeps the phosphorus insoluble and therefore unavailable to plants. This is why, while there is often phosphorus in the soil, we must add soluble, available, phosphorus. Phosphorus is present in most fertilizers, in super phosphate, triple super phosphate, colloidal phosphate and other forms. You may choose to use one of these. The commercial phosphate fertilizers have been treated to make them more soluble, but that is a temporary situation in our New Mexico soils. Colloidal phosphate must be added in much higher concentrations than the others to provide sufficient phosphate to the plants. In any case, the soil eventually binds the phosphate as it reacts with the calcium and forms insoluble calcium phosphates. Addition of organic matter, sulfates, sulfur, or other acidifying materials will help prolong the availability of phosphate, but this is an ongoing process. At least there is no concern that a gardener will get sick from properly using these sources of phosphorus."

Here is a link that might be useful: New Mexico State University on bone meal and Mad Cow

    Bookmark   December 14, 2013 at 3:25PM
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