“REGULAR PATROLS OF YOUR
PLANTS ALLOW YOU TO SPOT
PROBLEMS QUICKLY, SO SPEND
A FEW MINUTES EVERY DAY
JUST ASSESSING WHAT SHAPE
YOUR PLANTS ARE IN.“
FIVE
DOWNY MILDEW OR POWDERY MILDEW?
These fungal diseases are both bad news, turning up
as fluffy fungal growth on foliage and fruit that spread
rapidly through your plants and turn your crops to mush.
That’s where the similarity ends, though. Downy mildew
is a damp-conditions fungus. It likes the cool, wet
conditions of spring and autumn, and it turns grapes,
lettuces, peas, and spinach to white, moldy rot. Powdery
mildew prefers dry conditions. It turns up in the heat of
summer on zucchini, squash, and cucumbers, weakening
plants and bringing the harvest to a sudden, early stop.
Telling them apart:
The climate and time of year tells you which of these
two nasties you’re most likely dealing with. They look
different too. Powdery mildew is obvious, appearing
on the upper surfaces of leaves as a dusting of white.
Downy mildew is more difficult to diagnose. It can
cause leaves to develop pale yellow
or green blotches. Turn them over
and you’ll find a corresponding
patch of fluffy fungal growth.
“TO MAKE THE RIGHT DIAGNOSIS,
GROWERS NEED TO DIG A
LITTLE DEEPER, ASK THE RIGHT
QUESTIONS, AND WEIGH ALL
SORTS OF CLUES.”
Treatment:
Downy Mildew: Pick off affected
leaves to slow the spread. In
greenhouses, open vents whenever
possible and water at the feet of
plants to avoid wetting their leaves.
Powdery Mildew: Keep plants
well-watered, as dry roots make
them more susceptible to the
disease. Pick off infected leaves to
slow the spread. Also, look for resis-
tant varieties to grow next year.
When you first discover your sick plants,
diseases and pest attacks can seem
like mysterious disasters. Don’t panic,
though. Take time to methodically work
through the symptoms and figure out
exactly what’s wrong. Once you know
the ailment, like any good doctor, you
can prescribe the right medicine. With
the right prescription, and a little luck,
your plants should bounce back and
make a full recovery.
Maximum Yield
57