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Carnivorous Plants/Post-insecticide mold?


White residue
White residue  
QUESTION: Hi Jeff/Jacob,
A couple of weeks ago I posted on here and you advised me on treating scales with Acepahte (Orthene).  I followed your instructions and treated all of my plants with the 1 tsp. insecticide per 1 gallon water solution about a week ago (October 11th).  The scales appear to be drying up and dying off but now it looks like every plant I treated (12 in total) has mold.  The plants are all in the soil they came with (from you guys) or in the pearlite/peat moss/orchid bark mix discussed in your volume 3 dvd.

I have some Safer brand sulfur based fungicide but, is it safe for the plants to use a fungicide so soon after having the insecticide on them?  Is there a better/more potent brand to use? I sometimes have trouble with mold in my tropical sundews when they are indoors and this fungicide doesn't seem to work well - I end up re-potting everything after treating them for a few weeks with no results.  I don't want to have to re-pot all of my nepenthes, too.


ANSWER: Hi Portia,

Unfortunately, this becomes a pretty ubiquitous problem in houses during the colder times of year since we have higher spore counts when houses are closed up.  Some non-chemical things that will help are to take your plants outside occassionally and water them with large quantities to help flush the spores away.  It also flushes away excess nutrients from natural decomposition which the fungi feed on.  I like to take the hose on low and run lots of water through a pot.  If you have fungus on the plants themselves that's probably from decomposing scale insects.  Rinsing the plants themselves will help with that.

For chemical control, the sulfur is best used before you see the mold appear.  It's more preventative than curative.  Some others to try would be Chlorothnil (Daconil).  This is a heavy gel that you can spray on soil.  It is available at most garden centers.  Also, quanternary ammonium compounds that are actual disinfectants are made in horticultural preparations.  A couple horticultural preparations include Physan 20 and Consan 20.  These you usually have to order online.  With those, mix it according to directions, then spray the soil surface.  Don't flood the soil with it, however, since it would sterilize the soil.  Those products can also be used as a fungicide on tougher plants like Nepenthes and Sarracenia, but will damage delicate plants like butterworts and sundews.  The Physan/Consan products also don't have an much of an odor (Daconil doesn't either).

If you combine the flush with a spray follow-up you should be able to keep the soil mold free.  Of the two products mentioned above I'd lean a bit towards the Physan/Consan products since they are versatile.  You can also use them to sterilize surfaces with it.  The chemicals are found in many common household disinfectants.  The household products are cheaper, but they often contain detergents.

Because you're treating the soil, and not the plants, the fungicides shouldn't be any problem for the plants after the insecticide treatment.

Let me know how it goes.

Good Growing!

Jeff Dallas
Sarracenia Northwest

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

QUESTION: Thanks Jeff,
It seems pretty odd that all 12 nepenthes in three different rooms all had mold appear directly after the fungicide.  I've had issues with mold on sundews (in a completely separate room) before, but hadn't had any issues with the nepenthes.

I'll flush them all with water to start with, but before I go purchasing more treatments, would the  Chlorothnil (Daconil) be okay for use on the sundews and butterworts?  I was hoping to have one solution to treat everything with. If not, what is the best thing to use on the butterworts and sundews?

Thanks again!

Hi Portia,

Your Nepenthes had a pretty serious scale insect infestation.  Once you killed them the plants had dead bugs and their honeydew all over them; perfect breeding ground for mold.  This is why taking them out and giving them a good wash would be good along with washing away some mold spores in the soil.

Daconil should be fine on sundews and butterworts.  I've never seen any plant damage from it, but test it on one or two plants before using it on lots of them.  Pitcher plants have much tougher leaves than butterworts and sundews.

Good Growing!

Jeff Dallas
Sarracenia Northwest

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