Pests!
What (or Who) to Look Out For
I remember my first houseplant pest... Picture it: San Antonio, 2018...
I noticed my Hoya multiflora was looking a little sad. It had ben watered, it was receiving nice lighting. I decided to check it out with a magnifying glass.
I. Was. Appalled.
There were a few squishy-looking, fat little white things WITH LEGS!
To the internet I ran - fast as I could - searching for what these critters could be. I learned that mealybugs had taken up residence with my multiflora.
Since that traumatic experience, I have encountered a couple of other common houseplant pests and have become quite skilled at eradicating them, which means I'm dying to share lots of tips with you all!
This post will only address the pests that I've personally had experience with and successful eradication of, which include: Mealybugs, Spider Mites, and Gnats.
Prevention
Check out the Bringing New Plants Home post to see more detail, but the best way to prevent pests is to carefully inspect any new houseplant you purchase before it enters your home. If you are buying from an online source, make sure they have a stellar reputation, but also open plant mail in a separate room and inspect your new leafy loves before they are introduced to the space with the rest of your collection.
Mealybugs
These guys are furry-looking ovals and like to hang out in crevices. Mealies reproduce very quickly because females can lay hundreds of eggs at a time.
These bugs eat the sap from your houseplants, so you may notice some yellowing or deformed leaves. Over time, the plant will not be able to photosynthesize efficiently, reducing blooms and new foliar growth.
I have had the most success by using a qtip dipped in rubbing alcohol to snag each bug until I don't see any more. I've only had to do this three or four times to eradicate an infestation.
Gnats
I love talking about gnats. Wow, that's a strange sentence to write.
The reason I love this topic is because I had a gnat infestation from hell about a year ago and I have since learned how to prevent those nasty little nuggets from hanging out in my home.
This jug of magic seems a little expensive but a little goes a long way, and you won't need to reapply much at all. These are nontoxic granuals that contain a bacteria called Bacillus thuringiensis v. israelensis (BTI) that controls mosquito, gnats, and flies before they can fully develop.
There is one controversial aspect of using BTI: how to apply it.
I prefer to dress the top of the soil with the bits because it makes sense to me that, as I water my plants, the bits will release BTI into the soil evenly throughout the pot.
Other folks like to mix it into their soil mix, but I don't recommend that because it just doesn't make as much sense to me. I like to see what's happening and know that my application is even.
The other method is to create a BTI "tea" by letting the bits soak in the water you'll use to water your plants. I don't prefer this method because when I water my plants, it's usually because I notice a few of them need watered and I just fill up my can and give them a drink. I'm too impatient to add bits to that water and let it soak. It's likely that I would actually forget to water those plants by the time the water was ready.
Spider Mites
Spider mites are difficult because it's hard to spot them early. Once they infest a plant, they can do quite a bit of damage very quickly. Your plant will drop leaves and eventually die. A magnifying glass comes in particularly handy to notice these guys.
Move the magnifying glass slowly over the whole plant, keeping an eye out for anything that is moving. Often you will also find tiny eggs and black spots (feces) that are indications as well.
Spider mites like to feed on the softest, most fleshy parts of your plants, so you will typically find them much more on the undersides of leaves, particularly new leaves. You'll notice the plant's leaves will start to develop splotchy yellow spots from these mites munching.
My favorite way to eradicate spider mites is with a spray bottle of soapy water. Very little soap (a drop or two) in a small spray bottle of water does wonders. It will not hurt the plant in any way and will also help to control gnats that emerge from the soil.
Shake your spray bottle to distribute the soap and then spray generously to every part of the plant and on top of the soil. Then, use your fingers to gently massage the soap around the leaves and stems of the plant. The spider mites get caught in the soap very easily and are not strong enough to escape.
It is likely that you will not kill all of the mites and their larvae on your first go, so I recommend spraying the infected plant(s) daily for three days and then weekly until you see no recurrence.
General Methods of Pest Control
I have used Bonide's Systemic Housplant Insect Control and found it to be very effective.
Nematodes are also very effective, however do not use them in conjunction with a systemic pesticide as they will not survive.
Right now, I am using predatory insects as a means of control. I haven't been able to get ahold of ladybugs lately, but I did purchase praying mantids recently from a local nursery.
I see the occasional couple of spider mites here and there and I will be experimenting with praying mantids, lady bugs, and green lacewings over the next several months after which I will certainly report back with what I've learned.