Tag: moth

Who’s Camping in my Tree? Eastern Tent Caterpillars

eastern tent catipillars in webbing like tentThese guys are often confused with fall webworms, and bag worms, although all three are quite different. Eastern Tent Caterpillars (ETC) nests are active early in the season while webworms are active late season. ETC like to make their tent nests in the forks of branches, while webworm nests are located at the tips of branches. Fall webworms also enclose foliage or leaves within these nests. Tent caterpillars do not. Bag worms are single worm homes made of the foliage from the tree it has decided to call home. They mostly evergreens like junipers or arborvitae. I like to remember the difference like this… A bag can hold one, but a tent can hold many.

eastern tent catipillars in webbing like tentETC like wild cherry, other ornamental fruit trees, ash, willow and maple trees. They tend to make their tents on the eastern side of the canopy to take advantage of the early sunlight to warm them and start their digestive systems. After a about five instar, they fall from the tent, make a cocoon and after two weeks, the moth emerges. Mating occurs and the female deposits her eggs on the tree bark. Soon the eggs change into larvae, without leaving the egg and overwinter this way. In the spring, they emerge from the egg.tent catapillar netting

Other than their webs making trees appear unsightly, ETC rarely cause major problems unless their numbers become high. They are easy to control by waiting until nightfall, when they tend to go back to the tent and pruning the branch off. It can be disposed of via the garbage or campfire. If pruning is not an option, maybe these are:

  • Scrape off, discard overwintering egg masses.
  • Tear the protective tents out by hand before the larvae start to feed.
  • Control caterpillar movement and restrict access to feeding areas with Sticky Tree Bands or Tanglefoot Pest Barrier.
  • Apply Bacillus thuringiensis (Bt-k) or Monterey Garden Insect Spray (Spinosad) to the leaves to kill feeding caterpillars.
  • If necessary, spot treat with plant-derived insecticides as a last resort. Spray must penetrate silken tents for effective control.

© The Naturarain

It’s Zimmerman Pine Moth Time!

Zimmerman pine moth’s pitch tube on pine.

Any time there is a drought the previous summer/fall, Austrian, Scots, and red pines of the Midwest are susceptible to the Zimmerman pine moth (Dioryctria zimmermani). Why? In a nutshell, if a tree has enough water (turgid), any boring insect would get pushed out via the high pressure of fluids in the tree. This is why it it important to be sure your trees are getting enough water in the autumn.

White, tan or rust-colored resin flowing on the trunk could indicate the presence of the moth’s caterpillar-like larva. Finding one or two boring points is usually of no concern. Heavier infestations could cause weakened trees to become susceptible to other pests and diseases, eventually killing the tree. Heavily infested trees should be removed, so they don’t become a nursery for the moths.

It is critical to understand the life cycle of the Zimmerman pine moth [ZPM] for proper management. The tiny caterpillar over-winters in a silken cocoon-like structure just under the bark. Now, in the early spring, the caterpillars feed on the bark for a week or two, then tunnel into the main trunk, usually in a whorl area. Resin is pushed out by the insect causing a ‘pitch tube’. Fresh pitch tubes are white to tan, the consistency of lard and have a shiny appearance. Old tubes are yellow to grey, crystallized and hard, with a dull appearance. It is important not be confused by old tubes and new, which all together, may look like an infestation.

In mid-summer, the caterpillars pupate either inside the external resin or within their tunnels. At this time, it may be possible to kill the pupa by hitting the resin with a rubber mallet. I love organic cures!

The adults emerge as small grey moths in mid to late August. These moths fly at night and are rarely seen. Females lay their eggs on the trunk under the bark, thus beginning the cycle.

Management of ZPM begins with tree care including proper mulching, watering, pruning and fertilization. Healthy trees do not get attacked.

Insecticides should be applied during the two vulnerable times in the ZPM cycle. These times are mid to late April, as the over-wintering caterpillars become active, and in August, when the female moth has just laid her eggs and the caterpillars are searching for over wintering sites. Indicator plants for these spray times are when the saucer magnolia is in pink bud to early bloom, or in mid to late summer when panicle hydrangea is pink. Spraying branches and foliage is not necessary & wasteful.  Permethrin or bifenthrin are preventative sprays that are available for use by homeowners. Spraying at any other time is inefficient, as it has no effect and the insecticide may kill predators of the Zimmerman pine moth.

© The Naturarian

Giant Leopard Moth ~ Hypercompe scribonia

catapillar

The Giant Leopard Moth or Eyed Tiger Moth (Hypercompe scribonia) various forests having host plants on which the caterpillars forage extensively. Gardens, farmlands, woodlands and public areas can be frequented by them.

Females emit pheromones that are caught by the antenna of the males that successfully locates the female for mating. When mating is over, the female gets on with the process of laying eggs.

giant leopard moth

After the eggs are laid, the larvae come out of them which start feeding on the leaves where they emerge out of the eggs. As caterpillars, they assume the wooly bear appearance and go into hibernation for some time during the winters. But it might as well wake up for light foraging on milder days in the temperate regions. After sleeping over winter, it weaves cocoon from its body. It becomes the pupa after molting in the wake of spring. In the next few weeks, it transforms into an adult moth.

Host plants for larvae: cherries, plantains, violets, honeysuckles, magnolia, cabbage, sunflower, lilac, dandelion, pokeweed, willow, maples and other broad-leaved plants.

The dorsal aspect of the abdomen is iridescent, blue-black with orange lateral spots or occasionally orange with large blue-black spots. The legs also have iridescent, blue-black setae.

When threatened, adults ‘play possum’ and curl their abdomen to display their bright orange stripes. They also secrete a droplet of yellow, acrid fluid from the thoracic glands that is bitter tasting.

© The Naturarian