That would be... "A granular -applied- once a season..." M. I've been using a product containing Imidacloprid to control the beasts. A granular allpied once a year during Merodon flight/breeding season will usually keep the critters from infesting bulbs, especially the ones in pots. In ground control can be trickier. I'm less apt to apply Imidacloprid to the garden, as it is systemic and will kill other beneficial insects. Its use will also cause mites to become "extra-fecund". The population can explode and predators may have been eliminated. I always use pesticides will great caution, regardless of product. Sometimes, it's just necessary.