Common Pests Of Carnivorous Plants
Some people would be surprised that there are some bugs and pests that can be a nuisance and wreak havoc on carnivorous plants. Well, there are a few different insects that damage carnivorous plants with ease until they are properly controlled. We had a recent question on the blog asking for help getting rid of some bugs that were doing damage to a readers plants:
I have had a good sized terrarium since the start of the year with a number of different plants in it. They have been slowly dying off one by one, and one thing I noticed is that the root/stem is rotting off right at the soil base. Today I took a close look at the soil where my (now dead) venus flytrap was, and found a little colony of what looks to be fungus gnats that weren’t quite developed enough for flight. I’m nervous about using the typical chemical pesticide I’ve used on them before, as I’ve read that most CP’s have very delicate roots. I’m not really sure what else to do, but I checked your site and there isn’t really anything about common pests to CP’s and how to control/eradicate them. Any help you could give would be greatly appreciated. I have only 3 other plants in there, and I’m gonna be pretty sad if it’s a lost cause for those ones!!
Well I personally haven’t had much of a problem with common pests of carnivorous plants, but I have done some reading to help Paul figure out an answer to how to get rid of the insects that may be killing his insectivorous plants. Keep in mind that different species of CPs will react to different pesticides favourably or unfavourably and Paul doesn’t mention his specific species.
Fungus gnats and fungus gnat larvae – fungus gnats don’t do much damage to the plants, and may actually be a source of nutrition for the plants. The larvae, however, can eat roots and help promote pathogens/fungus damage on the plants as well. Fungus gnat larvae are a few mm long and are white and brown with a black head – making them quite easily recognized. There are a few pesticides that can treat them, but according to the ICPS the easiest (and safest) way to get rid of these pests is to use a thin layer of medium-grained sand on the top of the peat medium. This prevents the cyanobacteria and fungi from growing well and should stop fungus gnats from being able to lay their eggs.
Mealybugs – these insects belong to the order Hemiptera. They are whitish insects that hide out in the crown of your carnivorous plants – most notably the pitcher plants and bladderworts. They do damage by sucking out the sap from the plants. If you don’t see the bugs themselves, you may find a white fluffy substance on the plants. Mealybugs may be treated with pesticides such as Imidacloprid, Diazinon, or Malathion but pesticides are harmful chemicals. Thankfully, the ICPS and other sources have a safer solution: 70% rubbing alcohol with a couple of drops of detergent added. This can be swabbed on the insects and will dissolve their waxy coating – allowing them to dry out.
Finally, a possible non-pest problem exists. Over-watering or using the wrong water can definitely kill the plants over time. Most plants are adapted to pure/distilled water and tap water has salts and other compounds that are harmful to the fragile roots of carnivorous plants. If the roots rot off due to salts or being too water-clogged, the plants quickly die. One solution might be to refresh the peat with new substrate to allow for more air circulation in the soil and to ensure that proper water is used. Trying a thin layer of washed sand on the surface of the medium will help prevent slime and fungus and reduce insect loads in the terrarium.
Finally, always remember that pesticides can be dangerous chemicals with harmful and unknown side effects. They may damage plants or even your own health and this may be worse when using them to kill carnivorous plant pests such as fungus gnats and mealybugs since terrariums have little air flow and are kept indoors! Always read the label and use proper protective equipment when using chemicals.