I finally had some free time today to work on our lawn irrigation system. The first order of business was removing the yellow jackets nest that had been constructed around the underground valves for the sprinkler heads. A few week ago, I sprayed the nest and it appears that all of the residents departed for greener pastures or are now part of the pasture helping to make it greener. Nests of this type are engineering marvels; structured to maximize enclosed volume with a minimum of supporting wall material. Even more amazing is the fact that construction is done by multiple members of the colony in parallel. Imagine if 100 humans were each tasked with building one room of a 100 room hotel. What do you think the chances are that it would all just fit together perfectly? Regrettably, once I was able to access the valves, I could only isolate one of two that is stuck in the open position. Without a map to the location of other underground control valve boxes, my chances of finding the right one are pretty slim. I rarely outsource home maintenance work of this type but lacking the equipment needed to trace the control wires and locate the other boxes it is time to call in the pros.