There is one pest you will want to keep at bay if you’re growing succulents- mealybugs. Unfortunately this soft bodied insect is very common and it is pretty much inevitable that you will come across them on your succulents at some stage. It is very important that when they do make appearance, they are dealt with immediately.
Sometimes mealybugs can be missed as they lodge themselves in the tightest spots where the leaves meet the stalk. And this is how a full blown infestation can happen very quickly.
So what do you do? Pesticides may be the first thought, but mealybugs build resistance to pesticides and are well protected by a cottony cocoon. I have tried many pesticides claiming to control mealybugs but so far have not come across one that kills all mealybugs. Some people swear by 70% isopropyl alcohol, but in our experience it is not 100% effective either.
But how about drowning them while they are still on the plant?
Drowning mealybugs can work, but there is a chance the plant will drown as well. To kill mealybugs this way the whole plant will need to be submerged for more than 24 hours. The bigger the infestation, higher the likelihood some mealybugs will survive the drowning attempt.
We've done an experiment and submerged a plant where a mealybug egg has hatched, for 48 hours (we filmed this and the video is available below).
The result? Some mealybugs have died but some survived even after being under water for 2 days.
The plant did not look that well either, but it seems it will survive. However, we did choose a plant that is not particularly sensitive to overwatering. I can well imagine the more ‘touchy’ plants such as Echeveria Romeo, Lauii, Cotyledon Tomentosa or other succulents that like to be on the dry side would not survive this experiment.
In conclusion, I would not recommend drowning mealybugs.
We have another article that explains mealybugs in greater detail here- it is worth reading the whole thing to understand how mealybugs spread and the best ways to control them.