Bagworms hatch out and begin feeding every May. Check your junipers (including Italian cypress), bald cypresses, roses, Japanese maples and Indian hawthorns for chewed and missing foliage. We’re already seeing small amounts of damage, which means that this is the perfect time to head off more. The critters can be hard to see at first – they camouflage themselves, cocooning themselves in cut pieces of the leaves of the plant they’re feeding on. Once the cut leaves dry, they’re more obvious.
The damage these pests do will roughly double each week forward until the end of their feeding cycle. Spray soon if damage is seen. Once the bagworms are done feeding, they’ll tie themselves off in their cocoons and hang from branches, at which point chemical controls won’t work very well. Sprays throughout June are effective, but by mid-July and onward, the damage will be done. We recommend an organic control – spinosad – which we sell as Captain Jack Deadbug Brew. It’s safer than most sprays for people and pets, and effective. Hand removal of bagworms (when the shrubs and trees are small enough to do so) is also effective, but time consuming.
Most importantly, mark the week before Memorial Day next year on your calendar, right now. Any bagworms not controlled this year will emerge from those bags next year to infest the plant all over again. Early applications will stop the problem before it gets out of control again.