Bag Worms are out in full force this year throughout the Midwest and beyond. I have been noticing more and more bag worm infestation in Indiana and Illinois in the last few years. Previously, I rarely say them north of mid-Ohio. This Landscape Tip is crucial (and funny) so read it thoroughly eh?
With this in mind, here is all the information you need to know about bag worms and how to either prevent or get rid of them in your landscape. I’m also going to let you in on the ‘darker side” of the bagworm lifestyle! It ain’t pretty!
There are three main types of bag worms in the United States:
- Evergreen bagworm
- Snailcase bagworm
- Grass bagworm
Evergreen bagworms are the most common and are represented in the pictures here that I took at a golf course in St. John, Indiana. In reality, evergreen bag worms can be found in New England, all the way down to Texas but are more concentrated in the Midwest.
The Snailcase bagworm is found throughout the mid Atlantic but appears to be migrating towards the Pacific coast. Each type of bagworm creates a specific type of bag relative to its feeding habits. Most of the information here is about the evergreen bagworm.
BagWorm Life Cycle
Bagworms survive winter as eggs inside a tear-drop shaped bag found on a variety of trees and plants. The Evergreen Bagworm prefers evergreen trees and shrubs such as the blue spruce, arborvitae or cedar. There can be more than 800 eggs in each bag and they emerge as larvae in May. The larvae then use a combination of silken secretion and parts of the plant to create the bag around themselves. If you look closely at evergreen bagworm bags, they look very much like the plant leaves on which they infest. This larval stage is also when these little devils are eating and feeding on the plant; killing it!
In later summer and fall, when the bags are around two inches in length, the larvae suspend the bags pointing downward from twigs during which time they transform into the pupae or ‘resting stage’ before becoming adults. (adults are moths) Evergreen Bagworms’ bags look like small pinecones.
Bangin’ in the Bag
The male adult evergreen bagworm emerges in early fall as a moth, and flies around in search of females who are still in their bags. (If this bag’s a rockin’…don’t you come-a-knockin!) The female will produce pheromones that attract the males to her bag (it’s like Channel #5 for insects… c’mere baby, check out my hot bag!) The male inserts his abdomen into a hole in the bottom of the bag to mate. (Oh geeze, this is getting PG-13 now!) The female then lays several hundred eggs in a sack and then drops from her bag and dies. (dat’s right ho!) The eggs remain in the bag until May of the following year when the process starts all over again. (But what about the dude?..is he over at the bar smoking a cigarette?) …Adult male bagworms as moths survive just long enough to mate, but due to underdeveloped mouthparts, they can’t eat, so they die. (I hate those weak mouthparts!)
The Baby Bag Drag
As young larvae (before they have a ‘big bag’), Evergreen Bagworms spin strands of silk that carry them from pant to plant where they feed. This is why you sometimes see a line of arborvitae dying out in a row from bagworm infestation. When threatened, larvae will scoot inside their bag and hold the opening closed. The larvae feed on needles on conifers (evergreens). They will drag that stinkin’ bag all over a plant, feeding along the way. Around the country, they damage: orange trees in Florida as well as junipers, spruce, pine, willow, apple, maple, elm, birch and cedar trees across the US.
If the infestation is concentrated, they can completely defoliate a small shrub in about 2 weeks. Leaf damage is usually noticeable in starting in June and worsening in August.
How to ‘bag’ the Bagworm (Killem’)
When infestations of bagworms are diagnosed early (like June), control is fairly easy. Once population numbers begin to multiply and spread to numerous locations, control will be tougher but still possible. If bagworm infestations are not noticed until late summer, not only will their numbers be higher but the bagworms will have grown enough to make them more difficult to kill with an insecticide. The thicker the bag, the tougher the kill!
The easiest way to reduce the largest population of bag worms is the actually “pick” the bags off your trees and burn them in your firepit! In addition, you can use a general purpose tree and shrub insecticide spray. THe best types of insect control for Bag WOrms on trees and shrubs will work “systemically” which means they are taken up the plants roots and protect from the inside out! Here is the very best produce I have found to get rid of bag worms and pretty much any other insects as well.
Bayer Tree & Shrub Insect Control Conc.
If you have an infestation of bag worms this year, I’d definitely recommend you treat your evergreens early next year starting in June, just in case you missed any of the previous year’s bags!
Don’t you feel dirty now? I sure do.