Happy New Year!
Have you survived the Winter Vortex of 2018?
While we’ve endured more time below freezing this January than the one night of teens in January 2017, I’m fairly certain that the cold didn’t kill off any insect populations. At least the way we would like to see them: wiped from the face of the earth.
Because the ground in our region doesn’t freeze no matter how cold it gets, many insects find refuge deep in some soil or some mulch somewhere. And while fire ants don’t seem to be building new mounds, they are assuredly in survival mode as deep in the soil as they can get.
But an insect I want to focus on this week … one that I’m certain was not killed off by a few mornings in the 20s … is scale. I’ve always been fascinated how scale seems to survive freezing nights.
Take a look at evergreen shrubs like hollies and Japanese blueberries - or coppertone loquats and yaupons – and you may see some white dots here and there (Picture 1). There are also other types of scale, like tea scale on camellia.
Generally, they are easy to scrape from a twig or leaf. Many exude a reddish liquid when squeezed. Some ooze a yellowish liquid. This sweet liquid (honeydew) attracts ants and wasps to the plant. And it eventually attracts black sooty mold as seen in the second picture. If, instead of white dots or flakes, you seem lumpy bumps on the stems (as in the third picture), that too is a form of scale.
Right now is the best time to control scale organically. During our spring, summer and fall, the best scale controls are those chemically based with malathion. During the winter, however - especially when temperatures fall low enough to bring landscape shrubs and trees to dormancy - we can use, with authority, a true dormant oil spray.
The problem around here is that plants often get tricked into growing through our warmer autumns and early winters. But this early cold spell has ostensibly shut everything down, and this gives us a real dormant season!
So, take a walk around your landscape and look closely at all your evergreen shrubs. If you see any sign of scale, or if you had any sort of insect infestation prior to this week’s freeze, don’t hesitate to get out there with a dormant oil spray. Just be sure it’s a true dormant oil (above left).
There are oil-based sprays (above right) that are designed to work in all seasons, and if that’s what you have, you certainly can use it now. But those don’t work as well in the winter as a true dormant oil. Authentic dormant oils have a suffocating nature, and they are only safe to use on plants whose transpiration and respiration process is virtually shut down. When dormant oil sprays are applied at the wrong time of year they can suffocate a still-processing plant and damage many leaves.