Urban Forestry

The City of Livingston, along with most of the Central Valley of California, has been infested with an imported ‘Asian woolly hackberry aphid’. These insects are primarily host specific, meaning they target our hackberry trees.

Identification: These pests appear as small white fuzzy tufts less than 1/10 of an inch. They suck the plant juices from the leaves and excrete a sticky fluid that covers sidewalks, cars and anything below the tree. This ‘honeydew’ is basically sugar; it is unsightly and annoying but poses no health risk Control The City of Livingston City Manager and the Public Works Director have initiated control methods to manage this problem that has persisted for many years. A major step in control is Knowledge, for everyone involved.

Management: The City has treated many infected trees with an integrated pest management system(I.P.M.) One system is to inject an insecticide into the ground around a severely infected tree; this is taken up by the roots through the tree to the leaves where the target pest is. The second method is a foliar spray of horticultural oil onto the leaves. Both of these management practices are safe to people and the environment.

Control: Another useful management practice is for a resident to use a garden hose with a street of water "spray off" the insects from the leaves reachable from the ground. This will help to reduce the aphid numbers. This method will also wash the honeydew from the leaves which will reduce the amount of ants using it as a food source.