06/05/2026
🐛 Why are silky white nests showing up in cherry, plum, and apple trees across western Washington this June?
That's tent caterpillar season — and in cyclical outbreak years like 2026, a single tree can lose nearly all of its leaves in two weeks. Pacific Arboriculture sees the same pattern every late-spring across South King and Pierce counties: hundreds of striped larvae spilling out of a tent in a fruit tree, defoliated branches by mid-June, and a homeowner wondering whether the tree will survive.
Three takeaways from this guide that matter most for homeowners in Auburn, Kent, Federal Way, Renton, and Puyallup:
First, the treatment window for Btk (the standard organic biological control) closes by mid-May. By the time tents are highly visible, chemical or biological intervention has minimal value — the focus shifts to tree health and watering.
Second, manual nest removal works well on small ornamental trees within reach. Burning nests with a torch is the worst response — it kills the cambium and creates a wound that lasts years longer than the caterpillar damage.
Third, healthy mature trees usually survive a single year of defoliation. The combination that causes long-term decline is heavy defoliation followed by a hot dry summer with no supplemental watering — exactly the western Washington trend in recent years.
Read the full guide for species ID, what to watch after the leaves are gone, and how winter egg-mass scouting prevents next year's outbreak.
Tent caterpillars in PNW yards? Identify the species, when to remove nests manually, when to call an arborist, and how to prevent next year's outbreak.