Bagworms are very destructive to trees and shrubbery, and highly destructive of the evergreen tree arborvitae, juniper, and spruce. These insects can have destructive effects, defoliating and even killing plants, without any control applied, and also without any bagworm treatment.Â
This season plan will describe how to treat bagworms, bagworm treatment timing, and how to prevent them from ruining your landscape.
What Are Bagworms and Why Are They a Problem?
Bagworms are caterpillars that build protective bags that are coated with leaves and twigs, using the silk. Such bags help them avoid the attention of prey and complicate their destruction using pesticides when they do become prey. They consume foliage of plants, eliminating leaves and needles, crippling plants in the long term.
Typical symptoms of an infestation of bagworm include:
- Small sacs, appearing like spindles, are suspended on branches.
- Wilting or loss of leaf.
- Evident feeding injury to leaves or needles.
- Plant stress/dieback.
Unless controlled in their early stages, they might lead to irreparable destruction or even loss of life of ornamental plants.
Why Timing Is Critical for Effective Spraying
40% of homeowners in the US have experienced a pest infestation. Everything depends on bagworm treatment timing. Infant larvae are more prone to insecticides than adult larvae. When they swell in size and their bag becomes thick, no treatment is very effective, as the bag serves as a very good shield.
Reasons why early treatment is important:
- Targeted sprays are more useful when it comes to killing young larvae.
- Bags that are thinner offer less protection.
- There is more activity on the feeding side, exposing more to treatments.
- Later in the season, fewer eggs are laid.
Also, it is nearly useless to spray after the bagworms cease to feed and pupate. This is why it is important to understand their life cycle and schedule your treatment with a bagworm control calendar to correspond with it.
Spring: Monitoring and Early Prevention
As spring is getting underway, bagworms start to hatch. It’s time to develop a tree and shrub survey program. Keep an eye out for new small bags and feeding damage.
Spring action checklist:
- Look for signs on accessible plants every week
- Discard any bags from last year
- Look for early signs of larvae
- Apply preventative insecticides if there were infestations last year
Late spring preventive treatments can be used if you’ve had infestations before.
Late Spring to Early Summer: The Ideal Spraying Window
Bagworms are most commonly treated late spring to early summer.
Best practices for spraying:
- Time treatments to coincide with early larvae (May-June)
- Use thorough coverage (including branches in between foliage)
- Apply when the wind speed is low
- Repeat applications as necessary
When it comes to the product, you may not know when to apply it and may need the professional services of lawn and tree care companies (like CitiTurf) to assist in making the right choice at the right time.
Mid to Late Summer: Managing Growing Infestations
During mid-summer/late summer, the bagworms became bigger, and their protective bags have thickened. This is the stage where chemical treatments are much less effective, as in this case, the insects are covered.
At this stage, you can do the following:
- Visibly pick and take off bags.
- Bag that contains rubbish, dispose of in sealed bags or use soapy water.
- Keep on checking the health of plants.
- Use sprays only as a single measure of control.
Although there are still a few more powerful insecticides that can achieve success, the results are irregular. This phase underlines that it is better to take action at an earlier period in the season.
Fall: Preventing Next Season’s Infestation
As the fall approaches, the bagworms do not eat and begin to transform into adults.
Fall prevention tips:
- Check trees and bushes carefully.
- Get rid of and destroy a lot of bags.
- Target evergreens and already infected plants.
Having a bag that could carry hundreds of eggs at the same time, even a small effort could make a great difference in regard to the number of eggs that could be eliminated the following year.
Winter: Off-Season Maintenance and Inspection
Winter Pest management is often neglected, yet there is an excellent chance to be ready for the next growing season. Without the leaves and with more branches exposed, it becomes easier to see bagworm infestation signs and remove any remaining bagworm bags.
Winter maintenance tasks:
- Cut acacia trees with pruning.
- Take off the leftover bags.
- Dispose of dropped debris at the age of plants.
- Make a spring pest control plan.
Although bagworms are dormant during a season, the preemptive work is done during this time, which will allow someone to control these pests better in spring.
In Conclusion
Bagworms need to be controlled very well on a year-round basis with a bagworm control calendar, and timing in both stages is a very crucial factor. The larvae are tiny, hence they can be easily controlled during the late spring through early summer. However, common checkups, hand weeding, and some periodical repairs will all result in success as time goes by.
