Tropical Plant Health: Pests! - Ritchie Feed & Seed Inc.

Tropical Plant Health: Pests!

Your prized houseplants spent the warm summer months basking in the sun but now they are back indoors for the winter; but something seems to have moved in with them! Don't panic - it is possible to keep unwelcome visitors away- or to evict them from your pots and your home. Here is a list of common houseplant pests and some easy treatments to make your tropical plants a no-fly-zone! 


Aphids may very well be the most commonly known unwanted houseplant pest. Aphids are green, brown, red or black soft-bodied insects that suck plant juices causing deformation of leaves and blooms. They are found on the underside of leaves, usually on the newer growth. They deposit sticky honeydew on the leaves, which can lead to sooty mold. They reproduce quickly and may also spread plant viruses.

Aphids are easy enough to squish by hand, but to get rid of a whole colony, follow these instructions: rid the plant of all aphids by rinsing them off either outdoors with a hose, or in a shower or in your kitchen sink. If that doesn't do the trick, then spray with a insecticidal soap. Check back every few days for any stragglers and repeat the soap spray treatment when necessary.

Common Brown Scale

Scale can be a real problem indoors because it's a good temperature year round, which is an ideal condition for scale reproduction. Common brown scale are relatively immobile, so if they are contained to one plant, then you can control them. Homemade soap sprays aren't that effective on scale because the scale on the outside of the insect acts like a shield. You need to get it under the cap of the insect - use a commercial insecticidal soap for best results. Here's how you can most effectively remove scale:

- Place a plastic bag or some covering around the soil of your plant. This prevents any scale from falling into your soil.

- Get a commercial insecticidal soap, like those by Ortho or Safer's. Spray this on the plant so it's nice and soapy. 

- Run your fingers along the stems and plant leaves, turning up the scale with your fingernails. If you don't want to touch the insects, you can use an old toothbrush or even a toothpick, but you will have more control and accuracy with your fingernails. You may notice some scale fall onto the plastic bags; pick them up and discard them. Really be sure to look over the entire plant. Scale will also hide on stems where they are camouflaged! If available, use a pocket magnifier to look over the plant, including the creases of where the leaf meets the stem.

- After soaping up and scraping the plant, give it a good, sharp spray with your sink hose or your shower. Get all the soap off the plant so it doesn't affect growth. Keeping a plant strong, healthy and growing, can also keep insects away.

- Continue to check the plant again over the next three days to make sure you didn't miss any scales. If you missed any; repeat steps again. Check again once a week for the two months, just to make certain you got all them!

Common Whitefly

Whiteflies, which are more closely related to aphids and scale, can be mistaken for little white moths. They will easily take flight if you disturb them. Both the nymphs and adults of the whitefly use their mouthparts to suck juices from plants, which can cause leaves to yellow and fall off prematurely. Additionally, whiteflies, like aphids, exude honeydew, which becomes an attractant for sooty mold. If you allow whiteflies to multiply, then they can attack your plant enough to weaken it. 

Whiteflies are attracted to the color yellow, so the best way to catch them is by having yellow sticky traps and blasting the leaves with short bursts of water from a hose. Ortho Bug-B-Gon has also been effective with whiteflies. 

Red Spider Mites

Though these are technically not insects, they are a pest that indoor gardeners do not want in their home.  Spider mites are nearly invisible to the eye. You can see them using a magnifying lens, or can confirm their presence if there is a reddish film across the bottom of the leaves, some webbing, or even some leaf damage, which usually results in reddish-brown spots on the leaf.
If you detect spider mites on a plant, isolate it immediately,  and wash it thoroughly in the shower. Keep it in a space with a humidifier running daily, as Mites prefer dry conditions. Keep the air humid and the plant on the wet side and hopefully you can naturally rid your plant of the mites. Using an insecticidal soap (depending on the plant) will also help kill them; be sure to follow the product directions carefully. 

Fungus Gnats

Fungus gnats look similar to fruit flies, and are often mistaken as such. Their larvae, which are really the more cause for concern here, prefer to feed on fungi in the soil, which you can only get in moist conditions. They can eat plant material, but if the fungi levels are high, they often won't.
The adult gnats will often hang around the soil to lay eggs, but the adults are harmless. With a fork, scrape the top 1-2 inches of the plant's soil (without damaging the plant or roots) and let it dry out completely. Once your disturb the soil, apply some yellow sticky traps around the plant to catch the adults as well as a thin layer of diatomaceous earth. This will solve the issue fairly quickly. 

Preventing infestation in your Houseplants 

Keeping those pests from taking up residence in the first place requires a bit of extra work, but far less work than dealing with an infestation. Here are few simple steps to follow when you bring a plant indoors or a new plant home for the first time. 

- Inspect your plant before you buy it.  

At Ritchie's, we take great care that our plants are healthy, thriving and free of damaging insects, but there are exceptions when our plants could pick up a hitchhiker. That said, inspect the plant well before purchase, and if you do find something amiss, please let one of our on-duty experts know right away! 

- Use clean pots and soil

If you are repotting your plant, be sure to clean the new pot with soap and hot water to sanitize it. Use a fresh bag of soil for repotting to insure there are no 'leftover' pests from previously used potting material. 

- Put your plant in isolation

For a few days to a few weeks, keep you plant in a separate room or area than your current houseplants. Inspect the leaves, soil and stems daily for signs of unwanted insects. If it looks okay after a few days, move it out of isolation. If you are unsure, spray your plant with insecticidal soap (following instructions) to be extra cautious.