PEST

NAME
Bag Shelter Moths
Various Bag Moths Species

ORDER
Lepidoptera

Description of the Pest
There many caterpillars that constructs a shelter that they live in and also acts as protection from predators. These caterpillars feed solitary or are gregarious emerging at night to feed. The caterpillars (larva) have chewing mouth parts.

Bagworm(Thyridopterix ephemeraeformis) adult is a moth that produces caterpillars that construct a small elongated shelter from pieces of the host`s leaves and enlarges to 80mm long, as the lava grows. The eggs overwinter in an old female bag and many plants are attacked such as Thuja andAbiesspecies.

Bluegrass Webworm(Crambus teterrellus) is the larvae of the closed winged moth. Deposited bead-like eggs hatch in 10 days and the emerging lava feed on the leaves of Turf Grass. They then construct a silken tunnelled nest close to the soil and disguised with soil, leaf fragments and droppings. The larvae pupate in a cocoon under ground for 14 days. Infested lawns such as Stenotaphrum secundatum(St Augustine) have a ragged appearance and areas may die off completely.

Forest Tent Caterpillar(Malacosoma disstria) are bluish with white diamond-shaped spots along its back, feeding solitary on leaves and unlike the Eastern Tent Caterpillarnests are not built by binding twigs together, but by surrounds a single branch.

Juniper Webworm(Dichomeris marginalla)is a small larva to 12mm long and is brown with reddish brown longitudinal stripes. They form bags by webbing twigs and needles and appear during summer. The eggs are laid by a female adult moth with a wing span of 10mm and the immature larvae overwinter.

Procession Caterpillarsor also known asItchy Caterpillar(Ochrogaster contraria) is a fleshy caterpillar that grows up to 50mm long and is named because of its procession habit when moving about head to tail. It appears banded in reddish brown stiff hairs that are long and irritate skin on contact. The adult brown moth has a wing span up to 50mm across with two spots on its forewings.
Larva constructs large obvious shelters or bags using the twigs and leaves towards the end of the branches. These bags have some stiff hairs that cause irritation, old casts and have a mud brick-like appearance.

Tentmaker(Ichthyura inclusa) adult female moth is grey wings that are white striped and produces a black larva with yellow stripes. The larvae construct silken nests by binding twigs together and feed on the surrounding leaves. Commonly found in Populusspecies. A simular caterpillar The Eastern Tent Caterpillar (Malacosoma americanum) is found on Cherry trees.

Webbing Caterpillaris up to 25mm long with numerous black hairs along its body and constructs shelters that incorporate stems and leaves, becoming larger as the larvae grows. The silk ties are littered with debris and excrement. The adult moth is greyish with small markings on the wings.

Life Cycle
These insects have a Holometabolouslife cycle, i.e. an egg, larval, pupal and adult stage
The insect commonly pupates inside the bag, some pupate in the soil.

Distribution of the Pest
Larvae are active from mid summer through autumn, regardless of the climatic conditions.
They are found throughout coastal and inland Australia but the species vary with the climatic environment.. The moths fly to new areas aided by the wind and larva of certain species walk to a new host when the old one is depleted of food.


Gregarious larvae      Typical bag shelter

Period of Activity
Larvae shelter in the bag, where they feed during the day; they leave their shelter to continue feeding at night on the surrounding foliage.

Damage Caused
Larvae eat the leaves of shrubs or trees and a heavy infestation can cause complete defoliation. Ugly bags hang or are wrapped around the plant sometimes in large numbers. The shelters can be up to 300mm across and are constructed of twigs and leaves that are curled or joined together with silken thread, commonly look unattractive.

Leaves damaged by the larvae

Susceptible Plants
A wide range of plants are attacked by these moths and include Brachychiton ,Acacia,Baeckea, Beaufortia, Juniperus, Kunzea, Leptospermum, Melaleuca and Syncarpia species.The larva nest in the host plant or at the base and normally feed at night.

Nest at base of Acaciaspp.     Hairy caterpillar


Acer, Betula, Quercusand Populusspecies are susceptible to the Forest Tent Caterpillar.

Cotoneasterspecies are attacked by Webworm(Cremona cotoneaster) lava which skeletonises the leaves.

Turf grassesare susceptible to an infestation of Sod Webworm(Herpetogramma licarsisalis). It is a sporadic pest that appears from late summer to autumn. The adult is moth is grey-brown with black spots and has wings are up to 25mm across with transverse dark wavy lines. It flies during the night depositing eggs. The larva (caterpillars) feed on the leaves and construct a silken nest close to the ground where they live out there lives. When fully fed the larvae are up to 25mm long, green brown with dark spots displayed on its body.

Control

Cultural Control
Cut bags from the tree during daylight and destroy.
Use gloves as some bags and larvae are armed with irritating hairs.

BiologicalControl
Birds and lizards help keep numbers down, but these are not commercially available.
Bacillus thuringiensis a bacterial disease of insects in the order Lepidoptera applied to leaves late in the day may reduce the number of larva

Chemical Control
Systemic, contact or stomach insecticides may be effective if sprayed onto the exposed larva
Note
It is your responsibility by law to read & follow the directions on the label of any pesticide
Amendments by B. Sonsie Dip Hort Sc Burnley