Seasons

Seasonal pest calendar

The best time to deal with many pests is before they show up: bait ants in late winter, seal the house before fall invaders arrive, and knock down wasp nests while they're small. Exact timing varies by region; the dates below come from the extension sources cited, often for one state.[12][26][24]

The short answer

  • Late winter to early spring: bait ants outdoors as colonies begin to grow.[12]
  • Spring: watch for termite swarmers; winged termites indoors almost always mean an infestation.[27]
  • Summer: yellowjacket colonies peak and switch to scavenging sweets and meat by late summer.[24][30]
  • Late summer to fall: seal cracks before boxelder bugs, stink bugs, lady beetles, cluster flies and mice move in.[3][7][21]

Winter

  • Lady beetles, boxelder bugs and stink bugs that came in last fall wander out on warm days; they're the same insects, not a new infestation, and they don't reproduce indoors.[26][16]
  • Blacklegged ticks look for hosts any time winter temperatures are above freezing.[2][29]
  • In buildings with heated basements, termites occasionally swarm indoors in winter.[23]
  • Empty mud dauber nests can be scraped off safely in winter without spraying.[33]
  • Late winter is the time to bait ants outdoors, before populations build.[12]

Spring

  • Native subterranean termites swarm by day, mostly in spring after warm rain; in Mississippi's coastal counties swarms can begin in late January.[27][4]
  • Formosan termites swarm at night toward lights, late April to mid-May in south Mississippi and early May through June in Texas.[4][11]
  • Carpenter ants fly in spring or early summer; odorous house ant swarmers appear from May through July.[17][9]
  • Paper wasp and yellowjacket queens start new nests; knocking down a newly started paper wasp nest early in spring usually sends the queen elsewhere.[24]
  • Honey bee swarms are common from late April through June.[28]
  • Ticks: lone star and American dog tick adults and nymphs are active from about March through September.[29][32]
  • Flea numbers usually rise sharply in spring and early summer.[19]
  • Spotted lanternfly eggs hatch late April to June in Pennsylvania; clover mites invade homes in early spring.[10][31]
  • Hang codling moth pheromone traps in apple and pear trees in March to time treatments.[14]

Summer

  • Mosquitoes and house flies can go from egg to adult in about a week in warm weather, so empty standing water and remove garbage often.[22][20]
  • From spring to midsummer yellowjackets hunt insects; by late summer they scavenge sweets, meat and garbage around picnics.[24][30]
  • Bagworm eggs hatch in late May or early June; spray Bt on young larvae at the end of June.[5]
  • Cicada killers, large but rarely stinging, show up mostly in July and August.[25]
  • Lone star tick larvae ('seed ticks') can appear in large numbers in late summer.[32]
  • Drywood termites swarm in summer and fall in California.[18]
  • For bats, avoid exclusion when flightless young may be present, May through September in California.[13]

Fall

  • Seal cracks around windows, doors, siding, utility pipes and fascia before late summer to keep out cluster flies, stink bugs and lady beetles.[7][6][26]
  • Multicolored Asian lady beetles fly to buildings from September through November on sunny days after cool spells; brown marmorated stink bugs look for overwintering sites in September and October.[26][6]
  • Outdoor mice often move into homes as nights turn cold.[21]
  • Crickets come indoors in late summer and fall but usually die by early winter without breeding.[34]
  • Yellowjacket and paper wasp colonies die out with cold weather; mated queens overwinter elsewhere.[24]
  • Spotted lanternflies lay egg masses from September to December; scrape them into alcohol.[10]
  • Pick bagworm bags off evergreens in late fall, when they turn brown and are easy to see.[5]

How weather shifts the calendar

  • Ants may suddenly appear indoors when weather changes or outdoor food runs short, seeking food, water, shelter or refuge from heat or flooding.[12]
  • Springtails move indoors when it's dry outside; millipedes migrate into basements and garages after cool weather or heavy rain.[15][8]
  • Heavy rain can flush some mosquito breeding sites, but mosquitoes return a few weeks later as puddles stagnate.[1]

Sources

  1. Texas A&M AgriLife Today, “Texas A&M AgriLife entomologists: Floating fire ants, insect pests among flood hazards (August 30, 2017).” agrilifetoday.tamu.edu/2017/08/30/texas-am-agrilife-entomologists-floating-fire-ants-insect-pests-among-flood-hazards/ (accessed 2026-10-06)
  2. Centers for Disease Control and Prevention, “Where Ticks Live.” www.cdc.gov/ticks/about/where-ticks-live.html (accessed 2026-10-06)
  3. University of Illinois Extension, “Fall house guests (Sept. 23, 2019).” extension.illinois.edu/news-releases/fall-house-guests (accessed 2026-10-06)
  4. Mississippi State University Extension, “Species of Termites in Mississippi.” extension.msstate.edu/insects/termites/species-termites-mississippi (accessed 2026-10-06)
  5. Ohio State University Extension, “HYG-2149: Bagworm and Its Control.” ohioline.osu.edu/factsheet/HYG-2149-10 (accessed 2026-10-06)
  6. Penn State Extension, “Brown Marmorated Stink Bug (revised December 2017).” extension.psu.edu/brown-marmorated-stink-bug (accessed 2026-10-06)
  7. Penn State Extension, “Cluster Flies.” extension.psu.edu/cluster-flies (accessed 2026-10-06)
  8. Penn State Extension, “Millipedes.” extension.psu.edu/millipedes (accessed 2026-10-06)
  9. Penn State Extension, “Odorous House Ant.” extension.psu.edu/odorous-house-ant (accessed 2026-10-06)
  10. Penn State Extension, “Spotted Lanternfly Management Guide.” extension.psu.edu/spotted-lanternfly-management-guide (accessed 2026-10-06)
  11. Texas A&M AgriLife Extension, “Formosan Subterranean Termites, E-367.” extensionentomology.tamu.edu/wp-content/uploads/sites/3/2017/01/Formosan-subterranean-termites-E367.pdf (accessed 2026-10-06)
  12. University of California Statewide IPM Program, “Ants (Pest Notes, Home and Landscape).” ipm.ucanr.edu/home-and-landscape/ants/ (accessed 2026-10-06)
  13. University of California Statewide IPM Program, “Bats (Pest Notes, Home and Landscape).” ipm.ucanr.edu/home-and-landscape/bats/ (accessed 2026-10-06)
  14. University of California Statewide IPM Program, “Codling Moth (Pest Notes, Home and Landscape).” ipm.ucanr.edu/home-and-landscape/codling-moth/ (accessed 2026-10-06)
  15. University of California Statewide IPM Program, “Springtails (Pest Notes, Home and Landscape).” ipm.ucanr.edu/home-and-landscape/springtails/ (accessed 2026-10-06)
  16. University of California Statewide IPM Program, “Pest Notes: Boxelder Bug, Publication 74114 (July 2014).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnboxelderbug.pdf (accessed 2026-10-06)
  17. University of California Statewide IPM Program, “Pest Notes: Carpenter Ants, Publication 7416 (August 2009).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pncarpenterants.pdf (accessed 2026-10-06)
  18. University of California Statewide IPM Program, “Pest Notes: Drywood Termites, Publication 7440 (August 2014).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pndrywoodtermites.pdf (accessed 2026-10-06)
  19. University of California Statewide IPM Program, “Pest Notes: Fleas, Publication 7419 (September 2010).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnfleas.pdf (accessed 2026-10-06)
  20. University of California Statewide IPM Program, “Pest Notes: Flies, Publication 7457 (April 2015).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnflies.pdf (accessed 2026-10-06)
  21. University of California Statewide IPM Program, “Pest Notes: House Mouse, Publication 7483 (revised July 2025).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnhousemouse.pdf (accessed 2026-10-06)
  22. University of California Statewide IPM Program, “Pest Notes: Mosquitoes, Publication 7451 (revised April 2020).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnmosquitoes.pdf (accessed 2026-10-06)
  23. University of California Statewide IPM Program, “Pest Notes: Subterranean and Other Termites, Publication 7415 (May 2014).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pntermites.pdf (accessed 2026-10-06)
  24. University of California Statewide IPM Program, “Pest Notes: Yellowjackets and Other Social Wasps, Publication 7450 (March 2012).” ipm.ucanr.edu/legacy_assets/PDF/PESTNOTES/pnyellowjackets.pdf (accessed 2026-10-06)
  25. University of Kentucky Entomology, “ENTFACT-004: Cicada Killer Wasps.” entomology.mgcafe.uky.edu/ef004 (accessed 2026-10-06)
  26. University of Kentucky Entomology, “ENTFACT-416: Asian Lady Beetle Infestation of Structures.” entomology.mgcafe.uky.edu/ef416 (accessed 2026-10-06)
  27. University of Kentucky Entomology, “ENTFACT-604: Termite Control: Answers for Homeowners (revised March 2026).” entomology.mgcafe.uky.edu/ef604 (accessed 2026-10-06)
  28. University of Kentucky Entomology, “ENTFACT-606: Controlling Nuisance Honey Bees.” entomology.mgcafe.uky.edu/ef606 (accessed 2026-10-06)
  29. University of Kentucky Entomology, “ENTFACT-618: Ticks and Disease in Kentucky.” entomology.mgcafe.uky.edu/ef618 (accessed 2026-10-06)
  30. University of Kentucky Entomology, “ENTFACT-620: Controlling Wasps, Hornets, and Yellowjackets.” entomology.mgcafe.uky.edu/ef620 (accessed 2026-10-06)
  31. University of Kentucky Entomology, “ENTFACT-627: Clover Mites.” entomology.mgcafe.uky.edu/ef627 (accessed 2026-10-06)
  32. University of Kentucky Entomology, “ENTFACT-648: The Lone Star Tick in Kentucky.” entomology.mgcafe.uky.edu/ef648 (accessed 2026-10-06)
  33. University of Maryland Extension, “About mud dauber wasps.” extension.umd.edu/resource/mud-daubers (accessed 2026-10-06)
  34. University of Minnesota Extension, “Crickets (reviewed 2024).” extension.umn.edu/garden-and-home/home-maintenance/household-insects/crickets (accessed 2026-10-06)

Updated 2026-10-06. Built from sourced records. Spot an error? Tell us.