After mating, females lay their eggs inside the pupal cast skins and die.Īpparently when the newly hatched larvae reach a plant which is different from its parents' host plant, these insects often have difficulty in adapting to it and may die or may produce only a few offspring. During August and September, male moths emerge from their bags to mate. The bag is firmly attached by a sturdy silk band. In August, the worms mature and molt into the pupal stage. Upon reaching a suitable host, the worm begins to spin its bag, enlarging the bag as it grows. They hatch in May and June to small larvae that spin silken threads so the wind can blow them to a new feeding site. Winter is spent as eggs (500 to 1,000) in the mother's bag. Bagworms eat the foliage, defoliating the tree. Made to protect the caterpillar from birds and other predators, they blend in with the tree making them hard to see until considerable damage is done.
Bagworms are caterpillars of a moth that live in spindle-shaped bags made of silk and bits of foliage of the host plant. However, there have been a few Fraser fir Christmas tree fields where bagworm numbers have increased to the point that treatment was warranted. BAGWORMSīagworms ( Thyridopteryx ephemeraeformis), have a very wide host range among conifers but are usually associated with arborvitae or juniper. Many of these caterpillars are nocturnal feeders, making it hard to find in the day. Unfortunately, once the damage is noticed, the pest is usually no longer present.
Caterpillars have the potential to be of the more widespread, affecting many trees. These have included species of Campaea and Elaphria. Several species of loopers have been identified feeding on Fraser fir. Another pest attracted by harvested pines is the sawyer beetle ( Monochamus spps.) When white pines are harvested next to a Christmas tree farm, the weevils will sometimes move into the Frasers after feeding on the downed pines, resulting in damage to the terminals. One of the weevils that has attacked Fraser fir terminals is pales weevil ( Hylobius pales). Treatment of these pests is often unnecessary because in most instances they have left the tree by the time damage is observed. Damage is usually limited to a few trees. These pests usually eat the bark and/or needles, leaving lesions on the terminal.
There are many other pests that will attack the terminals of Fraser fir including Japanese beetles ( Popillia japonica), grasshoppers, weevils, caterpillars, and even mice. Damaged shoots or leaders can be pruned off the tree. No more trees will be damaged and damage has never recurred the following year. Treatment is not warranted for this pest because once damage is observed, the beetle is already inside the shoot or has already left. The white pine cone beetle usually affects only a few trees in a field. Fraser fir is not a good host for this insect and it does not appear to reproduce on Frasers. Sometimes a beetle can be found inside the shoot, or a second hole where the beetle exited can be found. The shoot or terminal wilts and dies at the point of entry. A tiny hole can be seen where it enters the shoot. In some years, the white pine cone beetle attacks Fraser fir, burrowing into the terminal or one of the branches in the first whorl. The white pine cone beetle ( Conophthorus coniperda) is a small, black beetle that burrows into the cones and shoots of white pines to feed and lay eggs. Insects Skip to Insects WHITE PINE CONE BEETLES
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