Tuesday, August 19, 2014

Aphids - Friend or Foe?

With the destruction they cause and how generally yucky they are, I would argue that aphids are certainly not our friends in the garden.  Especially if you grow anything in the brassica group of vegetables.  Aphids are tiny insects that proliferate quickly and suck liquids out of the leaves of plants.  They exude a sugary substance that attracts some species of ants.  In a relationship of mutualism, the  ants take care of the aphids; move them around, protect them, etc.  So maybe ants are not our friends, either.
However, there is a bigger picture.  Aphids are a huge food source for ladybugs, lacewings, praying mantis, spiders and other good guys in the garden.  Maybe these good predators eat ants, too.  There are a lot of birds that eat aphids:  chickadees, titmice, warblers, gold finch, and hummingbirds all eat aphids.
When the aphids get out of control, they can be removed by blasting them off of plants with water from the garden hose.  I have also resorted to removing plants that are covered in aphids.  But if their numbers seem to be low I leave them alone.  They can be washed off of vegetables at harvest time.  If I were to use some kind of poison to kill the aphids,  I fear what it would do to the beneficial insects and the birds.  And me - if the poison gets into the vegetables that I'm going to eat.
I have come to the conclusion that some aphids in the garden are a good thing (but still not my friends) in order to provide food for the true heros - the beneficial insects and birds that are keeping things in balance.  I always plant some broccoli or kale to attract aphids.  And I always find spiders and ladybugs hanging around those areas of the garden.  I also plant some flowering perennials that will attract hummingbirds - hyssops and salvias.
When practicing organic gardening, it's all about supporting the balance.
hummingbirds eat aphids - attract them to your garden with agastache or salvia

aphids on cabbage - out of control
ladybug patrols for aphids




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