Green ideas for pest control?
Getting a program for spring and summer pest control underway for the bonsai yard can involve thoughts on green pest management. Predatory and parasitic insects sound great, right? Buy a bottle, wave it around your bonsai, and sit back with a bloody mary and assume great and devastating things going on in miniature, the remains of your aphids, caterpillars, and spider mites strewn right and left.
Sadly, predatory and parasitic controls are rarely solutions to a pest problem for the average hobbyist’s bonsai yard.
The familiar and popular ladybug, an aphid predator (if you can get the adults to stick around long enough)
For a small cluster of bonsai on a few benches in the middle of a half-acre of grass, or a couple bonsai on rooftop garden in the city, green pest controls will likely be very disappointing. Both these places have one huge minus for supporting predation:
The absence of a functioning ecosystem.
Terrible place for biodiversity and green pest controls…a lawn
A brilliant place to simply leave alone with natural controls…a meadow
We might buy some ladybugs and release them, they fly away, the kids squeal and clap, and that’s about it. Ladybugs look great, and are a kind of poster-insect for green pest management, but will tend to colonize the neighboring yards rather than your bonsai.
The much more effective aphid predator, the ladybug larva, which will keep eating voraciously until there are few aphids left on one plant
For many full, established backyard gardens, though, green technologies may be a good path. Particularly those gardens that have a vast array of plant species in them, and especially those gardens that are dense and stable. Meadows generally have a lot of biodiversity, for instance, and are perfect for natural controls. My entomologist father was a huge fan of meadows.
Once we take one thing out of environments like this and try to grow it, like a tree, we get into trouble…
Parasitic and predatory insects are rarely going to work for bonsai outside of these rich environments…for that to work, bonsai would need to be in close proximity to foliar biodiversity (where it is hard to see bonsai to their best advantage.)
A predatory mite (red), with an aphid (grey) it has found
If you have a situation where it might work, like a complex, full garden, by all means do look into predatory mites, parasitic wasps, and others that can often effectively control or keep in check many pest problems that could get out of hand in simpler gardens. Many green controls are already present…predatory mites are often 20% of the mite population, being the faster moving mites on your plant (or on a white sheet of paper, following the ‘brushing the branch’ test.) Surprisingly, unless you have a lot of bluebottles zipping around, up to 95% of all flies in the backyard are predatory.
Most bonsai yards are simplified for better appreciation, and unfortunately we often need to resort to other means of pest control…and we can talk about that in another post.