Why calendar timing beats strength
Almost every failed DIY treatment fails on timing, not product. Grubs pushed a foot deep by October shrug off a surface drench they'd never survive in May. Queen wasps building new nests in April are interceptable; the same wasps in September are a different job entirely. This calendar encodes the windows university IPM programs actually target.
Spring (March–May): the intercept season
- Termite swarmers take flight on the first warm, humid days — the month to walk your foundation for mud tubes and discarded wings (signs of termites checklist).
- Ant colonies restart; bait stations placed now beat spraying trails that will just re-form.
- The exclusion week: seal foundation cracks, utility penetrations, and garage gaps before summer populations peak — it's the single highest-leverage week in the pest calendar.
- Queen wasp traps go up around deck perimeters early, when each caught queen is a nest that never happens (wasp danger meter).
Summer (June–August): the pressure season
- Mosquitoes peak — dump standing water weekly (the breeding inspection checklist covers the hidden spots).
- Ticks stay active in tall grass all season; check risk by region in the tick heatmap.
- Garden pests: caterpillars and beetles now, with grub damage appearing in lawns by late summer — the right spray month is August, not May.
Fall (September–November): the invasion season
- Wasps turn nasty — colonies peak in size and aggression exactly now; dusk is the safe handling window (removal cost guide).
- Rodents move indoors looking for warmth; a fast fall exclusion pass beats a winter trapping campaign (population math here).
- Boxelder bugs and lady beetles stack up on warm south-facing walls before finding cracks — those cracks are the winter problem, so seal in September, not December (full boxelder sealing checklist).
- Clover mites run the same south-wall migration on a different clock — the overwintering generation works in from mid-October to December (clover mite season guide).
Winter (December–February): the quiet fix
- Indoor rodents continue breeding; watch for droppings and gnaw marks in storage areas.
- Overwintering insects (cluster flies, stink bugs) wake on warm afternoons — vacuum, don't spray.
- Outdoor nests are dead. Any wasp nest visible now is decoration — remove it with a scraper, not a service call.
The common thread in every season: prevention windows open before the problem is visible. Extension services like UC IPM's home and landscape program organize their entire guidance this way — treat the source at the right life stage, and the visible problem never arrives. The U.S. EPA's IPM principles add the other half of the discipline: set an action threshold first, so a single sighting does not turn into an unplanned spray. Pair this calendar with the IPM treatment log to keep a record of what you actually applied, and when.