Some common bonsai pests

Since I’m enjoying the holiday weekend and not working on trees, here’s a post I’ve had in the cue for a few months…not pretty, but pests are something we all get to deal with. I’ll avoid treatment advice…that’s what labels are for, but I admit, I pull no punches when I see any of these among my trees. Everyday diligence reduces infestations, especially if you know what to look for and can spot it three trees down the bench.

Aphids are usually the first to attack. Oftentimes, it’s easier to spot the ants busy “herding” aphids on the tree. the presence of ants is a big red flag to inspect the tree for aphids. These multiply so quickly, that a few days is all it takes to lose a tree. I remember Paul James, the Gardener Guy stating that mother aphids give birth to aphids that wre already pregnant with more aphids. Epidemic! Other signs include their droppings, here on a Chinese quince:

Aphids tend to converge on the tender, new growth. Here are green aphids on a new Ume shoot:


Wooly aphids are easier to spot. Get them early, since when they get established, they will multiply quickly.


Pine tip moth invades my Kyokko Yatsabusa black pine, not bad, but a few here and there. If you haven’t seen it yet, be glad.

The life cycle starts last fall, and presents as the candles extend in the spring. At a certain point, they die, turn tan, and swell, with plenty of sticky tar surrounding the affected area. What’s happening?

In the fall, a moth lays eggs, which bore into the bud. As the bud extends in the spring, the larvae also grows, feeding on and killing the extending candle, resulting in a random candle (or more) that look like this:


Inside, here is what’s happening…gross!



Not exactly dangerous or life-threatening, but I’d rather nothing touch my pines but me!

More info is here:

Not to leave on such a nasty photo…here’s the KY this year, end of August:


Next up, mites! Often the scourge of juniper owners. Fortunately, I don’t have a photo of them on the tree, as I nuked the juniper as soon as the symptoms showed up. Hold a white sheet of paper under the suspected branch and tap it, then check the paper for very small bugs moving very fast…Here is an extreme example of mite damage on the top branch of this shimpaku. Be vigilant and check quickly if a branch begins to get pale. They breed quickly and spread fast!


Lace bugs are often found destroying azaleas. Infestations present as white spots on the leaf surfaces, caused by the moths sucking out the liquid from the undersides. Interestingly, those in full sun tend to be targeted more than those in some shade. These buggers are persistent, partly because they’re hard to get to. If you notice these symptoms, be sure to spray the tree from the back and undersides:

The culprit:


Now, a couple perfectly healthy trees to cleanse the palette…




Next week, one more about a fat little trident maple I’ve been compressing for about a decade.
To the US readers, enjoy your Labor Day weekend. Thanks for reading!


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