Last week, I addressed the influx of beneficial bark lice which can currently be seen making webs on some area trees.
That led to a few "thank you" emails, but it also prompted listeners to send me pictures of what they called "giant" bark lice.
Much like the messages I received that precipitated my heads-up on bark lice, these emails were both right and wrong. Right - the insects are "giant," but they are actually giant bark aphids. And these annoying creatures are anything but beneficial.
Fortunately, giant bark aphids don't spin a web for protection like bark lice, and that means you can kill 'em with just about any liquid insecticide. If left untreated, though, giant bark aphids will do what all aphids do — suck juices from the tree trunk and drip a mass of honeydew below which, in turn, will allow the formation of black sooty mold.
Like bark lice, we really haven't seen giant bark aphids in years, so this means they too are "cycling back." And that worries me a little, because giant bark aphids don't usually rear their ugly heads in these parts until late August through November. With infestations already present in July, this could be a very bad year for these nasty critters.
There are a couple ways to rid your trees of the problem.
First, blast them off with a water hose and treat the tree a day or two later with dormant oil spray.
If you want an immediate kill, go with malathion, isotox or orthene. I suggest a dormant oil spray a week later to ensure you kill any eggs or nymphs that may have been missed during the insecticidal spray.
Often the first sign of giant bark aphids will be the sticky honeydew under the tree, then the appearance of dark sooty mold. Cars parked under infested trees may be adversely affected by the honeydew rain.
If the honeydew is dripping harmlessly on nothing below, some entomologists say this short-lived insect will go away on its own. But opinions are mixed on whether giant bark aphids will actually kill oak trees. In any case, they can completely destroy entire limbs, especially on smaller trees.
The aphids are also found on hickory, pecan, sycamore, walnut and larger-trunked wax myrtles.
PHOTO: Texas A&M Forest Service