Some of the plants that are overwintering under the grow lights indoors have pest problems every year. Whiteflies, aphids, mites, scale, mealy bugs, and fungus gnats are the culprits, and the first outbreak is happening now: mealys and aphids.
I've got two small elephant bush (Portulacaria afra) plants under the lights, and their succulent leaves and stems are apparently the choicest greenery on my table right now.
I always notice the mealy bugs first on this plant. I never see them when the plants are outside, but as soon as they come indoors these soft, white critters appear.
They almost exclusively stay at the joint between the leaf and the stem...
...while the aphids roam all over the plant -- under the leaves mainly.
Aphids are more rare here, as I don't see them every year. The mealys though, I know them well.
I knew there were aphids from the sticky spots on the leaves:
Normally I would mix up some fresh insecticidal soap, douse this plant every few days, and that would take care of all of these soft-bodied juice suckers. The elephant bush seems to be sensitive to the soap spray though, if I remember correctly from previous experiments.
So I'm going to take a different approach with these this year: a systemic pesticide.
(Note that just before posting I remembered that I have tried this before, but don't remember how well it worked.)
I'm not one to typically use this kind of poison in my garden, but I have it around to help combat mites on some of my bamboos. I'll give it a try here and see if it works on these pests. It should...
It's not recommended to be used indoors.
It shouldn't be applied to plants that produce food.
It should not be used more than once a year... wow, lots of restrictions.
You should always be concerned about these chemicals since they're so potent. Almost 99% of this bottle is "other ingredients" (which is mostly water), and since you have to dilute this severely before using (768:1), you end up with one part active ingredient to 76,000 parts "other" (water). Wow.
Since the plants I'm using it on are in tiny pots nothing close to gallon size, I just estimated how much to mix into a half gallon of water. I used old jar lids to catch any runoff, as that's apparently the reason this shouldn't be used indoors (directions say that you can bring containers indoors after all excess water has dried).
I'm not sure how long it will take before results show. If I don't see the bugs dead in a week, I think I'll apply more. I know it says not to use more than once a year, but I assume that's to avoid soil contamination -- since these are pots multiple applications shouldn't matter.
If even that doesn't produce results, I guess I'll need to use the insecticidal soap even though it may hurt the plants. I know for sure that these pests are causing some harm, and they'll soon spread around the table...
At least the grasses are immune to any pest problems.