Bill Manning, an arborist with the City of Vancouver, says aphids make their homes on linden and tulip trees, and when they secrete waste, they produce a honeydew that drips from the tree leaves.
"The problem in Vancouver with the hot, dry weather is that it increases the ability of the aphids to reproduce at a faster rate than they would if the weather was cool and wet," Manning told On the Coast.
"So essentially the conditions that we have in Vancouver right now are great for aphids to reproduce."
According to the City of Vancouver's website, aphids, which suck the juices from plant leaves, rarely threaten tree health, but they can become a nuisance.
To deal with the outbreak this summer, Manning says city staff will spray insecticidal soap in locations where the aphid infestation is particularly bad. Starting next week, the city will also release ladybugs.
"The ladybugs are very much a biological control and with the increased [aphid] population, we release the ladybugs, the ladybugs can climb up the trees and have a feast on the aphids," Manning said.