From: djd@cbnewsg.cb.att.com (david.j.daulton)
Date: Thu, 15 Jul 1993 16:05:15 GMT

In article  flammia@lcs.mit.edu writes:

> My irises are turning brown, have a sticky liquid at the base and
> white worms in the bulbs. Why and what can I do about it?

I hate to be a defeatist, but I read an article in the newspaper a few
weeks ago that reflected my own feelings about bearded irises--thay
should be listed among plants that are too much trouble to grow.  (I
don't recall the other plants on the list--I think tulips were
included.)

The problem is, the particular pesticide that kills this iris worm is
one of the worst to have around.  So when my irises got wormy, I threw
them out.  That's a shame, because bearded irises are among the most
beautiful of flowers.

But not all irises get worms.  Try Iris pseudoacorus, Siberian iris
(Iris sibirica), or (I assume), Japanese iris.  Anyone have other iris
suggestions?
===

From: jwilson@bach.udel.edu (Jim Wilson)
Date: Thu, 15 Jul 1993 19:29:31 GMT

Borers can and do attack the beardless species as well, although many
of them not as vigorously as they go after the bearded with those big
juicy yum-yum rhizomes.  The versicolor/virginicas, native to many
parts of the eastern US, are favorite (original?) borer targets, and
these irises often manage to survive and prosper in spite of them.

Even though borers are a problem here (there are large sections of the
U.S. where they aren't), I still have a place in my yard for the
beardeds.  They were the first to reward my minimal gardening efforts,
and they seem to draw the biggest crowd reactions in the yard or cut.
My biggest problem with them is their constant "weed me" call.

The main current enemy of irises like Siberians seems to be the
vole--a leading hybridizer has one mounted and displayed in his living
room.  Probably with everything you grow, something is going to go
after it-- that's life.  I would add my vote for Siberians as one of
the most carefree garden plants around, all things considered.  --
===

From: jwilson@bach.udel.edu (Jim Wilson)
Date: Thu, 15 Jul 1993 21:40:24 GMT

bailey@butyng.bu.edu (Sherry Bailey) writes:
> So, Jim -- any preventative measures we start-up iris growers can
> take to reduce the likelihood of borers attacking our investments??

[There must me an iris analog to the old conductor's saying,]
["Never look encouragingly at the trombone section."        ]

OK, here goes:
1) Move to Colorado, or one of those big states out that way.
2) Be sure what you are planting is borer-free.  Look for entry holes
   on leaves and/or pieces of the rhizome bored out.
3) Do what is reasonable to avoid rot.  For mustard seed fungus or crown
   rot, if that is a problem, a new planting is a good chance to do a
   thorough treatment with Terraclor.  I usually do without that, but
   lots of areas in the south have reported problems of this sort.
   To inhibit bacterial soft rot, I usually add some agricultural
   streptomycin to my pre-soak water.  In any case, do the cultural
   things you should do avoid this rot--sunny location, good air
   circulation, good drainage, rhizomes not too deep, not too much
   nitrogen around, etc.
4) In the fall, do a very thorough cleanup.  Some people used to burn
   over the entire site, but that's a drastic step; I like seeing some
   green, and maybe the plants like it being there too.  Repeat early
   spring.
5) In the spring, when new leaves are about 6", do your attack thing,
   whether it is spraying with Cygon 2E or Lindane or unleashing the
   nematodes.  This is often mid-late April here.  Repeat in 10-14 days.
   If any escape that, you may be able to see them working their way down
   through the leaf and then you can then undertake hand-to-hand combat.
6) When you cut stalks off, cut them close to the ground on a dry day.
7) If you are a good moth hunter, you could patrol your beds at dusk in
   October. :)   I've never caught one myself, though I've seen some.

My first few years went just fine doing less than half of this stuff,
and I did find a few borers one year, but it wasn't the end of the
world by any means.  Some people only spray if they have seen a
problem, and others spray as a preventive measure, and others would
never think of spraying, so pick your philosophy and away you go.  If
others have other good tips I've missed here, we'd all welcome them.