Time for Bagworm Patrol

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Bagworms look exactly like they sound. They spend much of their life as worms living in bags. They are common throughout North Carolina and seem to prefer juniper and arborvitae as their home, although they can be found on other shrubs and trees.

Bagworms hatch in May and June and travel from one plant to the other by silk threads and wind. They will attach themselves to the stem of a shrub and begin to spin a bag using parts of the plant for re-enforcement. They also begin to eat foliage and can defoliate a plant when large numbers are present.

Bagworms are not particularly noticeable until numerous bags are seen hanging on a shrub. These bags can best be seen in the winter when leaves of deciduous trees are absent. In the early summer these bags will move when prodded, telling the observer that the eggs are about to hatch from the bag. Female bagworms never leave the bag, but in August the male bagworm emerges from the bag as a moth and mates with the female in her bag.

Effective contol with insecticides must take place during June and July while the bagworm is actively feeding and spinning it’s bag. Once the bag is spun and the worm is enclosed, chemicals cannot penetrate. When this has taken place, the only effective control is to cut the bags off the branches of the shrubs with scissors and then destroy the bags.

Bagworms are unsitely, when large numbers are present and girdling of the stem by silk threads used to attach the bag to the shrub can cause damage. The occasional bagworm is not a threat to a shrub so the homeowner must make the decision as to whether the infestation is severe enough to warrant chemical control.

Applications of Orthene, insecticidal soap or malathion are effective when applied at the proper time. At least two applications will be necessary at seven to ten day intervals. Follow the label recommendations for application rates and safe procedures.

Get out in your landscape now and inspect trees and shrubs for these hanging bags full of worms.