Expert: Sarracenia Northwest - 5/16/2010

Question
QUESTION: Can you tell me what this is on my plant and how to treat it? The plant is a ventricosa, about a year old, I keep it next to our south facing window on metal shelves and I live in the Northern Calif MotherLoad foothills, east of Sacramento. I've just repotted it with fresh soil and whatever this is, is spreading fast. I have four and they've been healthy as a horse, till now. I've got plenty of light and have shares in distilled water. I am sorry, I don't know how clear these pics will be, but with my eyesight it's very hard to determine just how clear the picture will be.

ANSWER: Hi Marian,

There really isn't anything wrong with the plant itself.  The discoloration you see is part of the aging process of the leaf.  It's occurring only on a single older leaf.  As the plant matures, the lower leaves will die off.  As long as the upper leaves look healthy and you're seeing new growth, the plant is essentially healthy.  The leaf in question likely got damaged during repotting and it's on it's way out.

If you see this spreading to the upper leaves, definitely write back with a photograph.  I'll also need more information about the type of soil mix you're using.  Overall, based on what you've already described, the plant is healthy.  Cut off the old growth when you can't stand looking at it anymore.

On May 17, we're releasing Volume 3 of the Grow Carnivorous Plant DVD series.  This volume will cover Nepenthes and some of the common problems.

http://www.cobraplant.com/DVD

Good growing!
Jacob Farin

---------- FOLLOW-UP ----------

QUESTION: Thanks Jacob for getting back to me so fast, I really appreciate it!
Whatever this is, is on the upper leaves(hope the pic isn't too blurry) The only leaves not affected is the brand new, beginning to unfurl leaves. The soil I use is a 1/1/1/ ratio of perlolite, vermiculite and peet moss ( spag.) and as I said before I've just repotted, is there an expiration date for any of these, always wondered. One of the forums said it looked like rust....?

Answer
This photo helped clue me in.  You might have a problem with thrips or some other pest.  The spots are rust spots, a type of harmless fungal infection.  It sometimes occurs on older leaves, and when it does, it's usually irregular in shape.  When it occurs widespread on the plant and the spots are uniform, then I think pests.

When an insect bites a leaf, the leaf becomes damaged, and the rust spot occurs.  Once the damage occurs, it's permanent.  There's no way to reverse the rust spot.  The most you can do is prevent new ones from forming.

Thrips is a common pest with houseplants. You may not see it since they're very tiny.  To control them, use Neem oil.  You can find preparations of this substance at your local garden center.  I prefer Neem because it's a natural product.  It also has a dual action in controlling pests and fungus.  The only drawback is that it smells hideous, but that's true for most insecticides.  Safer® makes a prepared solution of it.  Whichever brand you use, make sure to follow the directions as listed on the bottle.  You may need to repeat in 7 days.

Pyrethrin is also an organic compound that's effective in getting rid of thrips and other common plant pests.  Again, Safer® makes a prepared solution of pyrethrin.

If you want to use a systemic insecticide, use Disease Control by Bayer®.  A single application is good for 4 weeks.  This formulation will prevent insects, mites and fungus.

The only insecticide to avoid is soap.  

Good growing!
Jacob Farin