Excited For Aphids

Every year without fail, some of the leaves on my River Birch change, becoming weirdly distorted and deformed.

This leaf distortion is actually caused by aphids - Spiny Witch Hazel Gall Aphids, to be exact - which feed on birch leaves starting in the spring and then eventually move on to Witch Hazel trees for the second part of its life cycle.  The infested birch leaves ultimately shrivel up and fall off the tree prematurely.

So it's a bad thing for your tree to be attacked by aphids every year, right?

Surprisingly, it can actually be a great thing!  The infestation of aphids is usually not heavy enough to harm the health of the tree.  It does, however, attract all sorts of beneficial predators to the garden.

The infected birch is like a magnet for ladybugs.  There are always a lot of them on my tree.  They eat the aphids and lay their eggs there.  The larvae that hatch eat even more aphids and eventually turn into even more ladybugs for the garden.

ladybug larvae eating aphids on birch leaf

Other interesting insects attracted by the aphids include this Tree Cricket nymph. Tree crickets and their nymphs love aphids and scale insects and can be beneficial to a garden (though they can occasionally become a pest for orchards as they also like fruit).

Tree Cricket nymph on birch leaf

Believe it or not, there are actually beneficial wasps to have in the garden, such as this little Mason Wasp.  They prey on many larval insects including aphids and are non-agressive and rarely sting.

 My favorite things that are attracted by the aphids, however, are the birds.

Baltimore Oriole

Most of the birds that I see eating aphids on the tree are ones that I see commonly at my nearby bird feeders.  The Baltimore Orioles, though, have never come to a feeder (despite my attempts).  I only see these beautiful birds up close when they come for the aphids.

It makes you almost want an aphid infestation, doesn't it?