Winter Tree and Shrub

Contrary to the lawns that sprawl beneath them, our trees and shrubs are still plagued by foraging insects during the cooler and colder months of the season.

Towards Thanksgiving, the unusual and shocking sight of millions of little white moths can be seen in some areas. This insect is known as the Winter Moth. What you may not realize is that this is the same insect that you see first thing in the spring of the following season when the eggs laid by the adults in the fall hatch. The little green looping caterpillars are defoliators that cause damage ranging from what looks like shotgun holes in the leaves to complete denuding of the infected trees.

The presence of these moths is not uniform throughout the region; indeed there can be complete defoliation on one street and no damage on the next street over. The insect’s presence can be foretold by scouting for little brown egg masses laid on twigs and branches during the winter.

Control can be achieved through applying insecticides either before egg hatch with a product called Dormant Oil, if the insect’s presence in recognized before hatching. Dormant oil, also referred to as Horticultural Oil, is a highly refined petroleum that we dilute with water and apply to targeted trees and shrubs in the landscape prior to the onset of warm weather. Insects do not have lungs to exchange gasses within their bodies as humans do. Gasses are exchanged through organs known as spiracles on the surface of the insect’s bodies. These spiracles must remain unobstructed in order for them to function, just as with humans. The dormant oil forms a film over either the spiracles themselves or over the egg masses laid by the previous generation. The result is the same – the insects suffocate.

After hatching, an insect control known as Bifenthrin can be utilized. Bifenthrin is classified as a synthetic pyrethroid.

In nature, plants manufacture their own insecticides to protect themselves from being devoured. The most instantly recognizable natural insecticide is the nicotine in tobacco plants – in fact, the nicotine that occurs naturally is a full, red flag, skull and crossbones poison, a product that you do not want to be exposed to whatsoever.

Pyrethroids are produced naturally by the Chrysanthemum plant as an insecticide, and synthetic pyrethroids are compounds that are manufactured by science that imitate the molecular structure of the naturally occurring compound. Unlike nicotine, it carries the Caution signal word indicating that it is far less toxic to humans and the environment generally.

The Hemlock Wooly Ageldid is a highly destructive insect that infests stands of hemlock in both the forest and in the landscape. It is identified by the small white tufts that reside on the underside of the needles, appearing much like small pieces of wool. Contrary to most insects that complete their life cycle during the warmer months of the year, this ageldid is active during the winter.

Once diagnosed in the landscape, control is attained by applications of horticultural oil and soil injections of Merit, an insecticide that is taken up in the vascular system of the plant to the location of the insect. This effort must be on going as a single application of either would be ineffective – the insect has the ability to reinfest quickly.

Not all pests are insects. The winter is when we notice mammals feeding on our landscapes. Deer have become abundant in most of the Lawn Dawg service area over the past couple of decades and when food becomes scarce below a blanket of snow, evergreen plants become part of the menu. Deer feeding is easily recognized once you know what you’re looking for. Deer will only feed as high as their necks will stretch so affected plants will be denuded up to a height of about five feet. In especially brutal winters, I have seen entire landscapes consumed right down to the trunks on every plant. While unsightly, deer feeding is not considered all that problematic and rarely requires intervention. There are numerous products on the market that claim to repel deer and just as many old wives’s tales. My favorite (in polite company) is to put Irish Spring soap through a cheese grater and sprinkle it liberally in the mulch beds. Irish Spring? Where do people come up with these ideas? Tree & Shrub technicians will apply a highly concentrated product to vulnerable plantings containing Capscasin, the ingredient that makes hot sauce spicy – when an application is finished it, the landscape smells like a giant order of Buffalo Wings.

Below ground, moles and voles are busy tunneling around. Actually, they tunnel at all times of the year, but because lawns are growing rapidly the damage is easily masked by new growth. Not so during the winter. When moles and voles venture out into lawns in the winter, their tunnels look catastrophic. I cannot recall an instance where tunneling has disrupted a lawn to the point where reseeding or resodding is necessary. The damage will go away when the lawn comes out of dormancy. Trying to control them is pointless as well. The products are not particularly effective.

Even when it seems as though its too cold for anything to survive outside, ticks are still active in the landscape and the forest; when the weather outside is frightful, your pet will look so delightful. Be sure to keep up on the flea and tick controls for Fido!