Plant Diseases & Control
Spraying basics
1. It is best to use any type of spray in the
early morning or the cool of evening. Do not spray
when temps are above 80 degrees Fahrenheit!
Your plants may "burn" or have a reaction to what
you are using in excessive heat. This is known as
"phototoxicity."
2. Always perform a test on a small portion of
the plant material first.
Wait 24 hours to observe any negative reaction.
Proceed if there is no damage.
3. Really and truly...more is not better. If you
are not getting good results don't increase the
strength of these remedies without testing first.
4. Target just the area you need to treat.
Be careful... try not to harm the good guys! You
don't want to run off your allies.
5. When working with sprays or dusts always protect
your exposed skin and face. Some of these ingredients
can be very irritating to your skin, eyes and mucous
membranes, especially any hot pepper sprays.
Specific Disease Controls:
Apple tree scab: Grow any member of the onion
family around the base of the tree. Chives work
the best. You can also make a tea from chives and
use as a spray on your apple trees to help protect
from scab.
Brassicas:Keeping the soil pH around 7.0 to
prevent club root disease.
Peach tree leaf curl: This is a common disease of
peach trees. Sprays of horsetail tea, garlic (look
further down the page for recipes) and seaweed
can help to prevent this problem. Growing chives
underneath them also helps.
Neem Oil will help prevent rust disease, black spot
and can act as a general fungicide.
Potato scab: When planting your potato sets put
some wilted comfrey leaves in with them to
prevent scab. Also keeping the soil for your potato
patch with a pH of 5 or below (acid) or a pH of 7
or above (alkaline) to prevent scab.
General Disease Controls
Apple Cider Vinegar Fungicide:
For leafspot, mildew, and scab.
Mix 3 tablespoons of cider vinegar (5%
acidity) with one gallon water and spray in the
morning on infested plants. Good for black
spot on roses and aspen trees too.
Baking Soda Spray:
For anthracnose, early tomato
blight, leaf blight and spots,
powdery mildew, and as a general
fungicide.
Sodium bicarbonate commonly known as baking soda
has been found to posses fungicidal properties.
It is recommended for plants that already have
powdery mildew to hose down all the infected leaves
prior to treatment. This helps to dislodge as many
of the spores as possibly to help you get better
results. Use as a prevention or as treatment at first
signs of any of the diseases.
To make: Mix 1 tablespoon baking soda, 2 1/2 tablespoons
vegetable oil with one gallon of water. Shake this
up very thoroughly. To this mix add 1/2 teaspoon of
pure castille soap and spray. Be sure to agitate your
sprayer while you work to keep the ingredients from
separating. Cover upper and lower leaf surfaces and
spray some on the soil. Repeat every 5-7 days as needed.
Chive Spray:
For preventing apple scab
and downy mildew on cucumber,
pumpkin and zucchini.
To make: Put a bunch of chopped chives in a heat
proof glass container, cover with boiling water. Let
this sit until cool, strain and spray as often as two
to three times a week.
Compost and Manure Teas:
Many people have success with manure tea keeping
blight and other pathogens away from plant. Soak the
area around plants and use as a foliar spray. Do not
use on seedlings as it may encourage damping-off
disease.
Fill a 30 gallon trash can with water. Let sit for
24 hours to evaporate the additives (use rain water
if you can). Add about 4 shovelfuls of manure to this
and cover. Let it sit for 2-3 weeks, stirring once a
day. Strain and apply as needed.
Various manures supply nutrients as follows:
Chicken manure: nitrogen rich, use for heavy
feeders such as corn, tomatoes and squash.
Cow Manure: potash: use for root crops.
Rabbit manure: promotes strong leaves and
stems.
Horse manure: leaf development.
Compost Tea:Make and use just the same as you
would the manure tea. This is another terrific
reason to compost all those prunings, grass
clipping and kitchen wastes.
Corn and Garlic Spray:
Fungus Preventative.
This blend is surprisingly potent preventative
spray to protect your plants.
To make: Gather a handful of corn leaves, clematis
leaves (any kind) and as much of the paper like
outer leaves of garlic as you can. Process thoroughly
in a blender. Then mix with sufficient water to
make a thin liquid. Let sit for an hour, strain and
spray on plants as a preventative.
Couch Grass Rhizome Tea:
For preventing mildew and fungus disease.
To make: Put a handful of fresh rhizomes
in a glass pot. Pour 1 quart of boiling
water over rhizomes, cover and let steep
for 10 minutes. Strain, let cool and use
right away.
Elder Leaf Spray:
Elder leaves have fungicidal properties and
may be useful against mildew and blackspot diseases.
To make: simmer 8 ounces of leaves in 16
ounces of water for 30 minutes. Stir this
thoroughly, then strain. Take 16 ounces of
warm water and mix with 1 tablespoon of
castille soap. Add soap mixture to the elder
water, spray as needed. Note: Set your
sprayer to a coarse or large droplet setting as
this mixture will tend to plug a fine setting.
Garlic Oil Fungicide Spray:
For leaf spot and mildews.
To make: Combine 3 ounces of minced garlic
cloves with 1 ounce of mineral oil. Let soak
for 24 hours or longer. Strain.
Next mix 1 teaspoon of fish emulsion with 16
ounces of water. Add 1 tablespoon of castille
soap to this.
Now slowly combine the fish emulsion water
with the garlic oil. Kept in a sealed glass
container this mixture will stay viable for
several months. To use: Mix 2 tablespoons of
garlic oil with 1 pint of water and spray.
Horseradish:
Preventative for fungal
disease.
Penn State University announced in 1995
that minced horseradish holds promise
in decontaminating wastewater and now
says it may clean contaminated soils
as well!
Penn State's center for Bioremediation and
Detoxification reports that minced horseradish
combined with hydrogen peroxide can completely
remove chlorinated phenols and other contaminants
found in industrial wastes. Experiments involve
applying the mixture directly to tainted soils
or growing horseradish in contaminated soil
and rototilling the roots just before applying
h
ydrogen peroxide!
The cleansing properties of horseradish have been
known for more than a decade, however creating a
purified form has been far too expensive.
This method has proved to be just as effective,
but at a fraction of the cost!
Horseradish Tea:
You can also make a tea from horseradish roots
to use as a preventative spray for fungal diseases.
This is especially useful against brown rot in
apple trees. The white flesh of thehorseradishroot
also contains significant amounts of calcium,
magnesium and vitamin C.
To make: Process one cup of roots in food processor
till finely chopped.
Combine this with 16 ounces of water in a glass
container and let soak for 24 hours. Strain liquid,
discard the solids. Now mix the liquid with 2
quarts of water and spray.
Hydrogen Peroxide Treatment:
To prevent bacterial and fungal problems
on outdoor plants use hydrogen peroxide!
Hydrogen peroxide will prevent the diseased spores
from adhering to the plant tissue. It causes no
harm to plants or soil, however don't use on young
transplants or direct seeded crops until they have
become established.
Spray plants with undiluted 3 percent hydrogen
peroxide that you can buy most anywhere. Be sure
to cover tops and bottoms of leaves. Do this
once a week during dry weather and twice a week
in wet weather. This works as a preventative. If
you already have problems use this as a direct
treatment.
Milk for Mildew:
Milk with its' natural enzymes and simple sugar
structures can be used to combat various mildews
on cucumber, asters, tomato, squash and zinnia
foliage. Use a 50/50 mixture of milk and water.
Thoroughly spray plants every 3 to 4 days at first
sign of mildews or use as a preventative measure.
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Milk can also be mixed at a rate of 2 ounces milk
to 18 ounces of water and used as a spray every 7
to 10 days to treat mosaic disease on cucmber,
tomato and lettuce.
Tomato Virus Protective Spray:
To prevent the many viruses that attack tomato
plants this simple remedy really works! The
antitranspirant protects the plant surface against
disease spores. The skim milk provides the tomato
plant with calcium. A calcium deficiency is
common in tomato plants.
Antitranspirants can be used to protect many
plants against bacterial disease before they attack.
They are harmless and will not block the pores of
the plant tissue.
To make: Mix 1/2 teaspoon of antitranspirant (like
Cloudcover, Wiltpruf etc.) with 8 ounces of skim
milk, and 1 gallon of water. Spray plants. Clean
out your sprayer when done and flush with fresh
water..
NOTE: an equivalent of prepared powdered milk
may be substituted for the skim milk.
Removing leaves on the lower portion of the plant
may help lessen contact with disease spores and
certainly won't hurt the plant.
Seedlings:
Damping off disease.
Always use a sterile growing medium like mixes with
vermiculite and perlite for your seed starting as
these should not contain the fungi that cause
damping-off. Water your seedlings with warm water
that has been left to sit for an hour or more to
dissipate most of the chemicals that are present
in tap water. Using cold water stresses the seedlings
leaving them vulnerable to harmful organisms.
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1. Chamomile Spray: Chamomile tea is an excellent
preventative for damping-off. Use on seed starting
soil, seedlings and in any humid planting area.
Chamomile is a concentrated source of calcium,
potash and sulfur. The sulfur is a fungus fighter.
This can also be used as a seed soak prior to
planting.
To make: Pour 2 cups boiling water over 1/4 cup
chamomile blossoms.
Let steep until cool and strain into a spray bottle.
Use as needed.
This keeps for about a week before going rancid.
Spray to prevent damping off and anytime you see
any fuzzy white growth on the soil.
Chamomile blossoms can be purchased at health food
stores and usually grocery stores.
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2. Seaweed Spray: A seaweed spray which is so rich
in nutrients and everything that seedlings require
can also be used to prevent damp-off.
Make a strong mixture adding 2/3 cup of kelp
concentrate to 1 gallon water, spray.
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3. Horsetail Tea:
(Equisetum arvense)
The common horsetail plant, which is very invasive,
is rich in silicon and helps plants to resist fungal
diseases via increasing their light absorbing
capabilities. Use on peach trees to control peach
leaf curl.
Use on most plants to combat powdery fungi, and on
vegetables and roses to control mildew.
You can use this on seedlings and plants in closed
environments too!
Great in greenhouses! Prevents damping off.
To make: In a glass or stainless steel pot, mix 1/8
cup of dried leaves in 1 gallon of unchlorinated
water. Bring to a boil, then let simmer for at
least 1/2 hr. Cool and strain.
Store extra concentrate in a glass container.
Will keep for a month.
Dilute this mix, adding 5-10 parts of
unchlorinated water to one part concentrate.
Spray plants that show any symptoms of
fungal type disease once every 4 days. Spray
your seed starting mixtures to prevent
damping off.
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4. Spread finely milled sphagnum peat moss on the
soil surface of your seed beds or flats.
5. Sprinkle powdered cinnamon on soil
surface...yes this can work!