I have an apple tree that has had some aphids the last couple years, and also a lot of ant activity. Although the tree is growing so well it's not a big problem, I still want to minimize the presence of aphids. I found a natural insecticide for ants & roaches, in which the active ingredient is mint oil. I wondered: 1) if this may serve as a repellent to ants (which encourage aphids to thrive) if sprayed on the trunk. Probably it couldn't hurt anything, so I may try it; 2) if it would kill or supress aphids; 3) if it would be phytotoxic if I tried to kill aphids or other pests on the foliage; 4) if planting peppermint at the base of the tree would be no less effective against ant activity. Actually I have peppermint at the base of another tree about 7 feet away, which hasn't had aphid or ant activity the last two years; however, this tree, of another variety, has had weak growth and may not be attracting aphids like the vigorous one.
This might help http://www.zerowaste.sa.gov.au/prog_garden.php http://www.yates.com.au/Products/PestControl/InsectsConcentrates/WhiteOilInsecticide.asp Liz
That first link mentions planting onions, garlic or nasturtiums to deter aphids; however in an apple tree, the ground is quite a way from the branch tips the aphids infest. In fact I have garlic chives at the base of the tree. I was planning on putting some nasturtium seeds there in a couple weeks. It's true I am trying to encourage natural enemies by the companion planting and not spraying anything. I did use the jet of water technique once last year; that is kind of fun, but not hugely effective. Thanks for the links.
Biggam, did you use the Bug Blaster Sprayer? I just bought this Bug Blaster today. Mine is severely infested so I decided to use insecticide since young leaves are growing. Insecticide has to contact aphids to kill them, so it's a pain to spray the underside of the leaves. Once the infestation is somewhat under control, I will use the water jet spray to clean the rest. These aphids can fly too.
I introduce ladybugs to control aphids. I also plant dill and fennel to attract a parasitic wasp that targets the aphids.
There are ladybugs around here already, a few different species at least. When I have time, I'll put links for info that Michigan State U has learned from researching native perennials and their attraction for beneficial insects. Last year I planted some Coreopsis to that end.
