Guest Author - Connie Krochmal
Generally, cacti and succulents require little attention. Yet, things can go wrong. They aren’t immune to insect and disease problems. These can strike when you least expect it.
So far as insects are concerned, the most common ones seem to be mealy bugs, scales, and white flies.
Let’s look at scales and mealy bugs first. I’ve seen these occur on aloes, jade plants, and gasterias. Chances are the problem didn’t occur overnight, even though it may seem so. Insects in the immature stages aren’t always easy to spot.
How do these insects find the plants? Sometimes, I wonder if they blow in on the wind.
Ants may be involved if mealy bugs show up rather suddenly. The ants treat the mealy bugs much as we do cattle. They consume honeydew, a sticky, sweet substance released by the mealy bugs. So, they transport the bugs to suitable plants, such as succulents. This can occur if your plants are outdoors either in pots or in a garden. Getting rid of the mealy bugs isn’t enough. You will also need to deal with the ant problem. There are suitable pesticides, both organic and chemicals, to kill ants. Never apply it directly on your plants.
Once the ants have been eliminated, it is time to remove the mealy bugs from the plants. The simplest way is to wash them off with a garden hose. This same method works for scales and aphids. You may need to do this several times. Repeat as needed. Be sure and wash off the underside of the leaves and all areas of the stem. This is hard to do when the foliage forms a rosette.
If only a few scales or mealy bugs are involved, I usually use a cotton swab
dipped in rubbing alcohol. The insect should come right off the plant.
What happens if these remedies fail? A final solution, which I have never used, is systemic pesticides. Typically, these are applied to the top of the potting soil. The plant absorbs the chemicals, which then kill the pest. Frankly, I would rather throw the plant away. I don’t want to be around chemicals. If an heirloom plant that had been in the family for decades, I might consider it. Otherwise, I would discard it and buy a new one.
Aphids can also attack cacti and succulents. But they aren’t usually a big problem. If present, they will be on flower buds and blooms. They are especially fond of the new growth on kalanchoes and echeverias. If you feel it is necessary, use insecticidal soap, but check to make sure the plant in question is listed on the label. This product can cause damage to some species. The same is true for other garden chemicals. Always check the label first.
Spider mites can attack cacti and succulents. So tiny they’re invisible to the naked eye, these are hard to detect. A hand lens can be used. If you rule out all the other possible causes for the problem, and find they aren’t responsible, then it may be spider mites.
Slugs and snails can attack cacti and succulents that are growing outdoors in gardens and pots. For these, I use the less toxic slug baits. Most slug baits are poisonous, unsafe to use around pets and children. There are several brands of these, including Sluggo. Though this product is relatively safe, I still wouldn’t want to use it around children. They might be tempted to pick up the pellets and eat them. There are other organic solutions to slugs and snails as well. You can create barriers of copper, such as old copper tubing. Slugs and snails apparently get a deadly shock when they touch this material. For this system to work, you’ll need to use the copper all around the perimeter of your cacti and succulent garden.
