I have high hopes every spring when I bring home new plants. My new plants usually look bright and green. By the end of the summer, though, some of them are ready to just give up. That’s ok. At least I’ve learned a little more than I knew before. This summer I’ve been learning about plant pests and how to recognize them. I’ve certainly had plenty of opportunity! My plants have all kinds of issues, as you’ll see.
I used to have a gardenia. It died a long, slow death. I didn’t know what the problem was, so I didn’t know how to treat it! In hopes that it might save other plants from the sad, sad fate of my gardenia, here are a few pictures to help you identify a few plant pests.
1. A squiggly line on a leaf might look like some kind of plant disease, but it is actually from a leaf miner. Leaf miners are larvae of moths or flies, and they tunnel through the leaf, leaving their trail behind them. I pluck off the leaf if I see something like this:
2. A dark woody bump on the stem or underside of the leaf might look like a natural part of the plant, but it is actually an insect called scale. What you see is really a hard shell over a bug that feeds on the plant sap. Scale varies in colors and size. Sometimes you can just scrape or flick it off the plant stem. Other common advice is to apply rubbing alcohol to it with a cotton swab.
This plant has a bad case of scale. The leaves are sticky with a honeydew residue as a result. For this one we cut off the branches with the worst of it, scraped the remaining scale off as best we could, and washed it with soapy water.
3. I think these are the worst. What looks like some kind of white fungus is really mealybugs. These white, fuzzy bugs cause a mess. They feed on the plant sap, weakening the plant and eventually killing it. If you notice these, you can wash them off with water or wipe them off with a cloth to get rid of them.
4. A pest that is hard to see is spider mites. These bugs are tiny, red dots that reside on the dry underside of leaves. When they feed on the plants, it gives the leaves a speckled, stippled appearance. The leaves eventually become dry and yellowed. You might also notice a few strands of web around the leaves. Spider mites can be hard to treat once they become established. If you catch them early enough, you can wash them off with water.
Using water is a common preventive measure against pests. The water washes off the dirt or dust that can harbor mites, and it usually takes care of the bugs and eggs that hide among the leaves. This is especially important for house plants that don’t get rained on regularly. I’ve had some success spraying or dunking my plants in soapy water. On my last post about plant pests, Jessica mentioned that garlic spray seemed to help with bugs in her garden. Any more ideas for how to take care of plant problems?