Jun 18, 2013 - 04:16 PM
If the shed is over water, you are limited by what you can use. There are no pesticides that can legally be sprayed, although Demon WP would work the best. If you can keep it off the water, it does a great job. Paint brush, roller etc, would work. Don't apply anywhere except under the eaves, not any place where rain can wash it off into the lake. I am not recommending you use Demon WP since it is not labeled for your specific use.
Essentria is actually a fairly good product. It contains oils and aromatic ingredients that kill spiders and repel them. EcoSafe is a good cleaner and helps to discourage cob web formation, and Alpine is a good contact kill.