Bag Worm Control - BT, Sevin, etc?

Hello all, hoping you can give me some input here ...

I built an arbor to grow my hops on over the gate to the swimming pool. I know it's probably not the most optimal setup for hop yield, and I don't prune very many bines, but it's more for decoration than brewing purposes - the hop harvest is just an added bonus!

Anyway, surrounding the pool fence we have arborvitaes, an evergreen tree/shrub. Last summer noticed an infestation of Bag Worms in one section of the arborvitaes, and sprayed Sevin liberally in the area.

It seemed to work pretty decently, but they are back again this year. Since we were on the look out for them, we're catching them much earlier. The bagworms seem to be tasting my hops as well.... I've already sprayed Sevin on the arborvitaes, however I don't want to spray that on my hops since I have a considerable amount of flowers and cones already.

I've read that a good control is BT (Bacillus thuringiensis) which is a bacterial toxin for caterpillar control. This toxin is reportedly not harmful to humans or pets (unless I suppose you're raising pet caterpillars ) and the toxin is broken down naturally in 3-5 days in the sun.

It looks to be a "garden safe" pesticide, however I just wanted to know what you all's take on it is.

For this season, since the bag worms have already made their bags and thus much less susceptible to pesticide ingestion/absorption, I'll probably just keep an eye on the hops and manually pick off the bag worms and throw them into the chiminea.

Then come early spring 2011, I will BT/Sevin the area before the bagworms have made their silk bags and are much more susceptible to the pesticides!


***CENTRAL NJ - Keep an eye out for these bag worms. We never ever had anything like this before, and didn't notice them until July 4th, 2009. By the time I sprayed the arborvitaes in mid July, significant damage was done, and the eggs were laid. In their first season, these pests killed a ~10 year old arborvitae and significantly impacted at least two others.

http://woodypests.cas.psu.edu/factsheets/insectfactsheets/html/bagworm.html

http://www.mylawnadvice.com/images/SpruceBagworms.jpg

http://www.lifeandlawns.com/tag/bag-worms/

http://www.nfs.unl.edu/foresthealth/bagwormimage.asp

***

Anyways, I'm not -too- worried about them this year since they don't seem to enjoy the hop leaves. Here are some pics of my pool-hops.

Second year centennials, rhizomes from freshops.com

One rhizome at the base of each side of the arbor.

Early spring, fertilized with chicken **** when cleaning out the coop.

BT is a good pesticide.. If you wanna go totally garden safe but still just as effective as BT, Monterey has a product called take down I believe that has spinosad in it which is completely organic. And spinosad kills all stages of worms/caterpillars.

Careful, 'organic' can mean several different things. In terms of a pesticide it may refer to chemical makeup, not necesarily 'safe to spray on food'.

OP - consider insecticidal soap but make sure to read the label on anything you use.

Thanks I'll check both of those options out for next year... I think I ought to be able to get through this year with just picking them off the hops. It really seems like they're coming off the arborvitaes and onto the hops; when I cut open the bag the worm does not seem to be very healthy. Then again, maybe it just isn't accustomed to eating hops, either...

You could also plant aster, daisies, and other relatives of such that attract bag-worm-larvae-eating predators. I had a bad bagworm infestation in some mulch I had brought in. They helped tremendously.

Don't forget to pick those bags and burn them. I hated those bastards.

That's a good idea, I will look into that! We have black eyed susans in the area too, but they don't seem to go into bloom until well into June or even July... which I believe is considerably after the larvae start spinning their bags...

I'm picking the bags ... though haven't had a need to burn any yet... whenever I find one I slice it open carefully making sure not to cut the worm, so I can see how healthy it looks... so far the ones on the arborvitaes are quite unhappy looking, but not dead completely..

Either way, I then play Queen of Hearts and "OFF with their heads!".

elwray said:

That's a good idea, I will look into that! We have black eyed susans in the area too, but they don't seem to go into bloom until well into June or even July... which I believe is considerably after the larvae start spinning their bags...

I'm picking the bags ... though haven't had a need to burn any yet... whenever I find one I slice it open carefully making sure not to cut the worm, so I can see how healthy it looks... so far the ones on the arborvitaes are quite unhappy looking, but not dead completely..

Either way, I then play Queen of Hearts and "OFF with their heads!".

Click to expand...

Burn the bags even if you kill the worm. Eggs are laid in the bags...

http://insects.tamu.edu/fieldguide/cimg247.html

Okay thanks for pointing that out -- I'll light them up one night this week... I've been throwing them into the chiminea for lack of a better disposal location.

Spinosad is animal and human safe.. Right now I believe it is the only 100% food safe pesticide on the market. It is whats used in sluggo plus and it has been OMRI approved.. Insecticidal soap works by suffocation. Which is fine if your going after aphids. Buuuuut Caterpillars will not be affected by soap.

From Tree Services Magazine (emphasis added)

Bagworms—Easy to spot because they use the needles of spruce and juniper to construct their outer woven “bag,” some homeowners have mistaken them for fruit or pine cones. Unfortunately, this case also prevents insecticide applications from effectively contacting the insect.

Bagworms overwinter as eggs within bags fastened to twigs. Eggs hatch late May through mid-June. After hatching, some caterpillars release a streamer of silk and are blown by the wind, establishing new infestations on nearby trees. Others begin to spin their tiny (l/8-inch) protective cases. Bags can grow up to 2 inches in length by the end of the summer.

Bagworm infestations on small trees and shrubs can be controlled by removing bags during the winter and spring before eggs begin to hatch in late spring. Destroy bags by burning, immersing in kerosene or by crushing. If bags containing larvae are discarded on the ground, the larvae can return to host plants.

Chemical controls are most effective if applied while bagworms are still small, usually from mid to late June. A midsummer cleanup application may also be required. Reduced-risk options for controlling bagworms include insecticides containing Bacillus thuringiensis (Bt), spinosad or neem oil (azadirachtin). Insecticidal soaps are also quite effective against young bagworm larvae, but may require repeated applications. These products generally have minimal impact on beneficial insects. Additional insecticide options for bagworm control on ornamental plants include acephate, bifenthrin, chlorantraniliprole, carbaryl, cyfluthrin, dimethoate, esfenvalerate, fluvalinate, lambda-cyhalothrin, permethrin and tebufenozide.

It will kill the eggs but it will not touch the bag worms them selves. It will just control them. Spinosad does not significantly affect beneficial organisms including ladybugs, green lacewings, minute pirate bugs, and predatory mites. Spinosad is not a contact killer. The bog has to eat what ever it is sprayed on for it to be affective. So predator/beneficial bugs are not usually harmed. The active ingredient is derived from a naturally occurring soil dwelling bacterium called Saccharopolyspora spinosa.. It doesn't get anymore organic than this.

Yeah, and cocaine is derived from a naturally occuring organism too, so it must be safe.
Insecticidal soap kills insects by breaking down their mucous membranes and dehydrating or suffocating them, kind of like pouring salt on a slug. So, in contrast to spinosad, it is a contact killer. That is all.
Personally, I'd spray everything with bifenthrin and not worry about ingesting a little pesticide, but if organic control floats you boat, have at it.