I am having a SERIOUS garden imp problem! I have at least 2 everyday! Once I came back for the first time that day and had 2 of them on my plants, thankfully the plants were close together so I was able to take them both out at once. Then about 3 minutes later one appeared on my trumpet vine! There went 50/70 energy. They ought to reduce the frequency of these pests.
Agreed, I deal with 2-3 imps and/or explosion bugs every day. My only suggestion: Plant in circles so that you can nail ALL your plants with one spell. It's a pain when your plant is ready to harvest and you have to wait 5 hours to get the energy to clear a pest, but also keep in mind that it takes quite a long time for pests and/or needs to kill of a plant. Specially the hardier ones like fly traps.
Maybe you're checking those plants too often. If a plant gets a pest, it's not going to die or even wilt within a couple of hours (at least, mine never have). Especially a plant close to becoming Elder, if you leave its needs un-addressed, it may just go Elder and you won't even have to spend Energy on it at all.
As for Fly Traps, the early stages seem to be the most needy. Since the second harvest, my Frozen and Deadly Fly traps have only gotten pests once, but before that, it seemed like every day.
Just like a new mom needs to learn not to freak out over every noise the new baby makes, we have to learn how to give our plants enough care without exhausting our Energy in the process.