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Aug 30

Maintenance crews encounter sap-sucking insects

Posted on August 30, 2018 at 1:45 pm by Peter Ibrahim

In August, a large portion of street trees along Hillview Avenue, Modoc Drive, Ringwood Avenue, Willow Road and Windermere Avenue experienced a severe aphid infestation. Aphids are small, sap-sucking insects that feed on plant fluids by piercing the foliage of trees and other plants. Minor infestation is common on many trees in our urban forest and does not pose a threat to a tree’s health or require treatment. This recent infestation was severe and specific to Modesto ash street trees. The result of the infestation was large quantities of “honeydew drip” excluded from the aphids, creating a sticky nuisance on surfaces below each tree.  

Consistent with the Integrated Pest Management plan, the use of chemical insecticides is minimized when reasonable and feasible alternatives are present. Treatment of the aphids was limited to spraying the tree canopies with a strong jet of water from an aerial lift truck to knock the aphids off the leaves, to effectively reduce the aphid population. Upon completion of the water spraying, the Maintenance Division scheduled additional street sweeping for the areas most impacted.