Jun 24, 2015 - 12:19 PM
EcoSafe Cobweb Cleanup and also Web Out are products designed for spiders and work well in some instances. Boathouses, by their very nature are a magnet for spiders. Water, humidity, and the elements surrounding these areas are a natural habitat for spiders. Getting anything to work for any period of time, is usually just trial and error.
There are no commercial insecticides that can legally be sprayed due to possiblity of drift and contamination of the water. The best products for this application would be those that are microencapsulated such as Demand, Suspend, Onslaught FastCap, etc. But again, these products are not legal to use around lakes or bodies of water.
Hope this helps.