When I attempted to start up our automated sprinkler system earlier this summer, I discovered that two zones were stuck in a permanently on position rendering the entire system unusable. Upon further investigation, I discovered that the valves for these particular zones were fully encapsulated in a large yellow jacket nest. Because yellow jackets mostly eat other insects and do very little pollination (their bodies are not fuzzy) and because I could see no other option to service the valves, I sprayed the nest last night with a product designed to neutralize the colony. I investigated this morning and detected no activity. I am not looking forward to the next step which is a careful dissection and removal of the hive. I am guessing that any survivors are going to be pretty angry so will approach the task with great caution.