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Re: Pea disease?

Hi again Tristan,

> I have 4 snow peas planted next to 4 snap peas on string trellises.  The
> snow peas have been producing since hitting 2 1/2 feet in height.  The
> snap peas have grown to over 6 feet and have just recently started to
> produce (since I started using shade material over them).  My problem is
> that suddenly (over the past week) the leaves on the pea plants have
> gotten a kind of dusty look.  The green leaves now look gray.  I am
> guessing this is some kind of disease, but I don't know what to do about
> it.  I have already lost one of the snap pea plants and as I have so
> few, I don't want to lose any more.  Any assistance in this matter would
> be most appreciated.

Sounds like powdery mildew, a fungal infection.  It's quite common with peas.
They prefer to grow in cool weather and after an extended spell of warm weather
and dry conditions they tend to lose resistance to disease.

Many of our peas get it every year, ... hopefully not before we've had a few
meals of them first!  I grow sugar snaps and snow peas and find both fairly
susceptible to powdery mildew.  Once they stop producing and look poor I pull
them and plant something else there.  We plant late crops of peas too, so that
they mature in the cooler weather of fall.  If you find that of the plants you
have one doesn't develop the disease (or shows better resistance) let some pods
mature and keep the seed for next year, they will pass on their resistance, peas
are strongly inbreeding.

Once peas have got powdery mildew it's difficult to control ... I grow
organically, and I've heard (but not tried) baking soda and oil sprays can
help slow it's usual rapid spread.  Wash the leaves clean of the powdery spores
with a hose and then spray with a mix of 1 tablespoon baking soda and 2.5
tablespoons of summer oil (a light horticultural oil) in 1 gallon of water.
Spray weekly after that.  This was researched at Cornel University and found to
help control powdery mildew on roses and squash plants.

Powdery mildew often takes advantage of stressed plants so the best preventative
is keeping them well watered and fed.  As well there are resistant varieties of
peas you can try in the future, such as Olympia and Knight.  I've grown
Olympia, it's alright.  I'll still keep growing sugar snaps though, despite
their susceptibility, they're a taste favourite.

> I have also recently found a small green worm just under the surface of
> my soil.  They were less than an inch long and about a little thinner
> than a pencil.  They were bright green and when touched, they squirm
> back and forth into a circle.  I am thinking that these are the culprits
> that have been eating my radish leaves.

Radishes are subject to the same pests that trouble cabbages.  They may be
diamondback moth larvae, which are green and about 1/2" long.  Unless they're a
real problem I wouldn't worry too much about them.

> I am new at the gardening game and really don't know much about critter
> or disease control.  Info on any good books or sites on this would be
> appreciated as well.

The Rodale books are pretty good, such as "Rodale's Pest & Disease Problem
Solver," "The Encyclopedia of Natural Insect and Disease Control," and
"Controlling Pests and Diseases."  A good insect ID book is "Rodale's Color
Handbook of Garden Insects."

There are quite a few entomology and garden sites on the WWW ... why don't you
check out "The Garden Launch Pad," a site organizing some 1500 gardening links!

  http://www.io.com/neighbor/

>From there you can take a link called "Diseases and Insects" which will give you
lots to check out.

> Thanks,
> Tristan Pfeffer
> Renton, WA
> t*@i405.com

Cheers!

--
 Bob Carter  -  bcarter@awinc.com
 Kootenay Bay, BC, Canada  -  Zone 6b
--

If you're not part of the solution, you're part of the precipitate.

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