If you want to manage bagworms, then your opportunity for treating the problem is quickly vanishing.

• Bagworm management is best achieved by hand removal from mid-August through the end of May (even on 15 ft trees). Every other bag removed will remove a female or a bag of eggs during this time frame.

• End of May through 4 July: apply with a backpack sprayer (commonly found at garden centers or box stores) Bacillus thuringiensis kurstaki (referred to as Bt) or spinosad around the middle to end of June.

• 4 July - early August (no later than mid-August): an application with same type of sprayer of either the spinosad (reduced risk product) or a pyrethroid (active ingredient ends in "-thrin") will provide control

• in August: Prior to insecticide application at least 20 bags must be removed, opened up and inspected for caterpillars. If there is a cocoon looking object inside most of the bags, then insecticide application will provide little control. If there are caterpillars in many of the bags, then an application within the next day or two of a pyrethroid may provide some suppression.

• mid-August: most likely hand removal is only option available. Bags must be removed and opened to see if there are caterpillars or cocoons.

The reason for inspecting bags in August for caterpillars is because the insecticides DO NOT penetrate the bag. Control is achieved by the caterpillar eating treated arborvitae foliage. If the caterpillar has formed its cocoon, then it isn't eating anymore; thus no control.

The spinosad products you have used provide decent to really good control of bagworms if applied early enough in the year.  Applications at this time of the year provide no control.  There are a number of Bt products available at garden centers or box stores but it sometimes takes searching for this because it isn't as common as other products.  The Bt works best on small caterpillars; consequently it is less effective after the 4th of July.  Spinosad products also work better on smaller caterpillars, and it has better efficacy against larger caterpillars.  Spinosad can be used with success until mid- to end of July.  The later into July it is used the less control you probably will obtain.  

At this point in the year it is usually to late to spray and not worthwhile.  I would remove bags and open them.  I suspect most will have cocoons inside; thus no control from treatments.  Mature females are present in September and they do not eat; therefore, in September any applications to control bagworms will be a waste of time and money.  Luckily you have decided to use products that are friendly to beneficial insects that like to eat bagworms.  This time of year there are many wasps (also parasitoids) that attack bagworms.  The parasitoids attack the caterpillars and kill them similar to the aliens in the movie "Alien".  The wasps are too small to sting and are no risk to people.