How gypsy moths kill trees

Fight against gypsy moths 2021 - other - nc to do

The gypsy moth is one of the most destructive of all tree pests in the USA Didier Descouens / Museum of Toulouse

If you have hardwood trees - especially oak or aspens - on your property and you live in any of the northeastern states or Virginia, North Carolina, Ohio, Pennsylvania, or Michigan, you need to keep an eye out for the destructive gypsy moth (Lymantria dispar).

The tree disease moth has been named "one of the most devastating forest pests in North America" ​​by the US Forest Service and "the most important insect pest of forests and forests" by the Penn State University Extension Service on shady trees in the eastern United States. "But they not only attack trees in forests, the larvae (caterpillars) can defoliate and kill shade and ornamental trees in urban areas and courtyards.

And they can be quite a nuisance crawling around patios, decks, and lawns, leaving debris from their feeding.

How the gypsy moth infestation spread

As the name suggests, the gypsy butterfly is not native to North America: it was introduced in Boston in 1869, widespread in the northeastern states by 1902, and fire discovered in Pennsylvania in 1932. Its introduction is actually quite interesting: Etienne Leopold Trouvelot was a portrait painter from Massachusetts from the 1800s collecting and identifying silkworms that could be used to make silk. But he brought gypsy moth eggs home from France in the late 1860s and cultivated them on trees in his back yard. When some of the larvae escaped, he notified local entomologists ... but nothing was done. Within a few decades, a gypsy moth infestation broke out in his neighborhood and began to spread. Although the state tried a number of control methods, the infestation continued to increase.

And the rest, as they say, is history.

With the extensive numbers, the moths can completely defoliate trees, making them vulnerable to attack and death from secondary pests such as the two-line chestnut borer and organisms such as the. And because it's not native to America, it doesn't have many indigenous predators that skyrocket its populations.

Although the gypsy moth is currently primarily found in the areas listed in the first paragraph of this article, isolated populations are discovered in new areas each year and the Forest Service sees this as inevitable and it will continue to spread over the next century.

Identification and harm of gypsy moths

The gypsy moth larva / caterpillar is fairly easy to recognize by the five pairs of blue dots and six pairs of red dots on its dark back, which is covered with hair. It is present - and spreads its destruction - from spring to early summer.

The adult female is brownish with white / cream colored wings. Although it has a wingspan of 2 inches, it cannot fly. The male is darker and slightly smaller than the female (1.5-inch wingspan). It flies. Both the male and female adults can also be identified by the inverted V coloration of their wings.

Adults perform after entering a puppet stage in early to mid summer and are present from July to August. During their short two-week lifespan, the adults mate, and the females lay 500 to 1000 eggs on branches, tree trunks, under bark, and in other sheltered places.

The egg masses, which are white to white, about 1 1/2 inches by 3/4 inches, remain dormant in winter to appear as larvae in spring when hardwood trees begin to bud.

Freezing temperatures below 20 ° F will kill gypsy moths and their eggs, but many egg masses can survive even harsh winters if they are covered and insulated by snow.

What can you do to keep your trees safe from moths

While many of the states where gypsy moths have been discovered have programs to reduce populations and slow their spread, homeowners can help with that effort. Below are recommendations that will help protect the trees on your property and slowly support the general expansion of the gypsy moth populations and geography.

  1. Know the pest. Get to know the gypsy moth: what it looks like, where it can be found; and how their life cycle unfolds. (See above for this information.)
  2. Know what the moth's egg mass looks like, then inspect the trees regularly and destroy any egg cells found.
  3. When traveling in areas where the gypsy moths are found, you should always check your vehicle and belongings for egg masses, larvae and moths and remove them.
  4. Do not transport firewood over long distances. Always buy locally if you are going to use it for a campfire or fireplace at home. When you visit a campsite, wait to buy wood near the site, then leave anything that you don't burn, don't take it home with you.
  5. Use strips of trees or other pest barriers on the trunks of susceptible trees to prevent larvae from moving up the tree. This is especially important if the butterfly caterpillars have been detected on your trees or in your neighborhood.

Gypsy moth control

Although only the larval stage of the gypsy moth causes damage - since the adult moths do not feed during their short lives, reducing and eliminating the adults and destroying the eggs will help keep populations growing.

  1. Adult males can be caught with pheromone traps, which limits the reproductive and growth ability of the population.
  2. If your trees are less than 12 feet tall, you can apply an insecticide product that is registered for bullfinch moth control. The University of Wisconsin Extension Service has a great chart listing the active ingredient, timing of use, and properties of some of the most common ones. This diagram is available at // learning memory. Uwex.edu / assets / pdfs / FR-171D. pdf. The state of Pennsylvania provides a similar map on its "Homeowners Guide to Gypsy Moth Management"; The diagram is on page 15 of the PDF file at // www. dcnr. Status. pa. us / cs / groups / public / documents / document / dcnr_20026635. pdf. When using a pesticide for a specific purpose, read and follow all directions on the label.
  3. If your property has larger trees or you want the work to be done by a professional, you can hire an arborist or certified pesticide applicator.