WHAT TO DO ABOUT POWDERY MILDEW
After years of research and experimentation in plant
physiology, microbiology and nutrition, the pieces finally
came together. Amino acids were the key. My well water is
loaded with calcium and magnesium carbonate, and lime
scale used to turn my reservoirs into rock gardens. But when
I started experimenting with an amino acid blend I received
from a vitamin manufacturer, there was no more lime scale.
So where did all of that extra calcium go? Into the plants. I
learned that certain amino acids stimulate root cells to open
up calcium ion channels, allowing the plants to take up calcium thousands of times faster than simple osmosis.
Calcium is taken up through the roots and transported
with the water throughout a plant. Some of the calcium
reacts with pectic acid to form pectin, the glue that binds
the cell walls together. Instead of water between the cells,
the plants had extra pectin between the cells. The plants
became stronger and healthier with thicker cell walls, and
I never had to spray a single fungicide or insecticide on
them the entire season.
So how does it work? When a mold spore lands on a plant
leaf, it wants to send down a feeding tube to get to the
water between the cells to germinate and spread. But when
the cell walls are thicker and there is an increased amount
of calcium-pectate between the cells, the mold spores just
sit there. By the time the germination tube penetrates
the cells, it dries up and dies. The pectin doesn’t kill the
powdery mildew, it just prevents it from becoming systemic
in a plant and spreading.
Increased calcium uptake also provides a reserve of natural protection against powdery mildew. Any extra calcium
a plant doesn’t use to strengthen the cell walls is pumped
into a storage vacuole inside the cell. If a mold spore does
happen to germinate, sensors on the surface of the leaf
detect the chitin in the cell wall of the fungus. Plants don’t
contain chitin—they contain cellulose. So when chitin is
detected, the plants send a signal molecule from the leaf
surface down to the vacuole, opening up calcium ion channels inside the cell. The calcium ions released start a chain
reaction that causes an oxidative burst—a plant’s first line of
defense against powdery mildew. This all means the judicious use of biostimulants containing amino acids will help
improve the plant’s natural resistance to pests and diseases,
without harming human beings or the environment.
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Maximum Yield USA | November 2015
Additional Prevention and Treatment Options
In addition to supplementing amino acids with a full plant
nutrition program, there are plenty of other ways to prevent
or eradicate powdery mildew from your garden.
Don’t Over-fertilize with Nitrates
Too much nitrate nitrogen encourages soft growth, which
means plants will develop large cells with thin cell walls,
making them more susceptible to powdery mildew.
Avoid High Humidity
High humidity sets up the perfect environment for molds
and mildews, and also interferes with calcium uptake.
“
Too much nitrate nitrogen
encourages soft growth, which
means plants will develop
large cells with thin cell walls,
making them more susceptible
to powdery mildew.
”