While our backs may have benefited from the mild winter, low snow totals could be even better news for the winter moth. Translation: a higher survival rate for the winter moth eggs and hatching in greater numbers. Winter moths are white/gray, and are often seen late in fall or early winter. These are male moths flying around looking for females (who are smaller and nearly wingless).
With topical temperatures this spring, the winter moths may begin emerging and looking to feed. Acting this week could reduce their populations and ease the tree and shrub damage they can create. Vegetation can survive a moderate season of infestation, however, repeated years or a severe outbreak could compromise the long-term health of the affected plants.
There may be a few signs on your trees to help diagnose if you may have a severe problem with winter moths. Fine droppings will accumulate (dark and smaller than a sesame seed). These dropping are often most visible on the windshield of a car that is parked under an affected tree. Additionally, on a very quiet windless night, you might even be able to hear them eating.
When winter moths hatch they start eating the vegetation around them. In the past, they used to primarily feed primarily on maple trees, but over the last decade their preferences have broadened and now also include other vegetation, such as fruit bearing trees, cherry trees and even perennial shrubs such as azaleas. When they exhaust the food at the site where they hatched, they use a silk like thread to drop from the tree. When they drop, they often land on other parts of the tree or other trees/plants. If they find the taste to their liking, they will devour that plant. Additionally, these same inchworms are capable of climbing back up a tree in search of additional food options.
There are two main types of treatment for winter moths:
A surface treatment in the form of a topical spray can be applied to the canopy of the tree. Since the leaves are what the winter moth larva are attracted to, this specific botanical oil will greatly reduce their populations.
A trunk barrier to trap the moths is also a successful treatment. The barrier consists of a sticky tape-like substance called 'banding material' which will prevent inchworms, ants and other insects that could instill damage from climbing the tree.
Information for this article was contributed by Wilson Farm, www.wilsonfarm.com.