QUESTION: Sometimes we see white, wooly-looking bugs in the air and all over the hackberry trees in the fall. At the same time, there is a black coating of something on everything under the trees. What is this?
These are Asian wooly hackberry aphids, which have been flying around Middle Tennessee for about a decade after making their way to the U.S. sometime in the mid-1990s. The aphid has a tiny mouth that resembles a beak, with which it pierces the leaves to extract the plant sugars. Then, like all aphids and
plant-sucking insects, they excrete a sweet, sticky waste product called honeydew, and in the heat of late summer, that substance grows sooty mold, the black substance you see on patio furniture, plants and anything else under a hackberry tree that is playing host to the insects.
I talked to U.T. Extension agent David Cook about the insects several years ago. He said that the feeding doesn’t cause serious damage to the tree. It’s considered mainly a nuisance pest.
If you feel the need to control the insects, Cook has suggested a systemic insecticide, applied around the tree’s root zone in the spring.
IF YOU THOUGHT last month seemed hotter than usual… you were right. Bobby Boyd at the National Weather Service sent me a list of factoids that made me sweat just to read them. Consider this:
August 2011 in Nashville was the 25th hottest on record. There were 24 days when the temperature was 90 degrees or higher, and one day when it bubbled up to 102. That was August 3, and it broke the record for that date of 100 degrees, which was set in 1952.
The average temperature for August was 1.8 degrees above normal. The average high was 92; the average low was 68.9. Three of the 10 hottest summers in Nashville have occurred in the last five years.
All this makes these past few days of cooler weather even more welcome. Fall, ready or not, is in the air.