December 2011. Aphids, said to be Phylloxera devastratrix, are present on pecan trees in a bamboo garden in Brazil. How can the aphids be managed without using chemicals?
There was no immediate response from members, on how to control the aphid without resort to chemicals. The life cycle is unusual and complex, with the aphids protected as adults inside galls or eggs protected inside overwintering dead females. See,www.treehelp.com/trees/hickory/pecan-hickory-iandd-pecan-phylloxera.asp.
The method of control given in this article involves using chemicals In the US, recommendations include an oil spray pre-bud break and insecticides (e.g., malathion) at 10-14 day intervals.
However, one method which may be relevant to the home garden situation is to apply a single treatment of imidachloprid as a ground spray before the aphids start feeding. If applied correctly, this MAY be a way of treating the aphids without killing bees and ladybeetles. Read the imidachlorprid label to see if it is recommended for use in this way, and also get advise from local pesticide professionals.It may be best to apply to a small part of the garden to gauge the effect.
Otherwise, use only the oil spray pre-bud break