Photograph of an AphidAphids are tiny destructive insects that can destroy you're bonsai in a matter of days if you're not careful.

What Are Aphids?

They're usually green, although they can also be black, brown, tan or pink. Their body's are tear-shaped / pear-shaped and they have two antennae and six legs (see picture).

As well as bonsai, they are harmful to lots of other different plant species due to their diet of sap.

They puncture a plant's phloem vessels causing the sap to flow into their food canals. They've also been known to feed on the sap in a plant's xylem vessels. Due to a loss of sap, a bonsai will display a lack of vigour; leaves can become mottled, yellow and brown, growth deteriorates, wilting occurs and in extreme cases, the bonsai itself can die.

Aphids are also responsible for transmitting diseases to bonsai and honeydew (which they create as a by-prodcut) can result in fungii growth.

So, if you spot an infestation of these nasty creatures on your bonsai, you must take action quick.

Getting Rid of Aphids

There are three techniques for getting rid of aphids that I know of and I've listed each of them below in order of effectiveness.

Home-Made Insecticide
Due to the amount of damage these wee beasties are capable of inflicting on crops, a lot of time and money has been spent by the agricultural industry on methods of getting rid of the blighters such as this insecticide that you can purchase from Amazon. Unfortunately, if you have an aphid infestation, time is of the essence and your bonsai could be ruined whilst you wait for delivery, so amore immediate solution is required.

Fortunately, you can create your own bug-killing insecticide using everyday household items.

Add a tablespoon of dish detergent and two teaspoons of vegetableoil to a spray bottle filled with water. You can also add a little rubbing alcohol or surgical spirit to make the mix a bit more potent but this is not necessary. Then simply spray your bonsai with the solution two or three times a day. This will kill the aphids (and many other pests) without harming your bonsai.

Pressure Wash
Depending on your bonsai species, you can blast the aphids off of your tree with a jet of water. Be aware that if you use this method on a delicate species that you could end up damaging your bonsai in the process. I'd advise placing your bonsai outside away from any greenery before spraying. Once parted from their hosts, the aphids will die of starvation very quickly.

The third and final solution is to introduce aphid-eating predators to your bonsai environment. A few laybugs / ladybirds or spiders will soon make mincemeat of your aphid infestation.

CLick here for more info on getting rid of aphids.