Should I be worried about a nest in the ground?
Yes, more than most other nests. Ground yellowjacket colonies around Ontario are large by late summer, sit right where feet and mowers go, and respond to vibration with a mass attack. Mark the entrance, stop mowing that section of the Ontario yard, and have it treated.
Is it safe to seal the hole where wasps are going into my wall?
No. This is the most common wasp mistake Ontario providers get called to fix, and the result is wasps in the living room. The right order is dust into the gap, a few days to a couple of weeks for activity to end, and only then caulk or mesh at the Ontario entry.
What time of day should a wasp nest be treated?
Most Ontario providers schedule nest work for early morning or evening for the same reason: the colony is home and slow. If a job must happen at midday, expect the technician to use a longer applicator and more protective gear on an Ontario property. Ask about the plan when you book.
How do I know if I have wasps, hornets or yellowjackets?
Photograph it from a safe distance and compare body shape. Slender with a narrow waist and long legs means paper wasp; short and stocky with sharp yellow bands is a yellowjacket, the most common stinging problem in Ontario. Very large, brown-and-yellow wasps flying at night are European hornets, which are established in parts of California and around Ontario.
Why are there suddenly so many wasps in late summer?
Two things happen at once in Ontario each late summer: colonies reach maximum size, and their diet shifts from insects to sugar. Workers that hunted caterpillars in June now scavenge trash and drinks. The colony will die at frost, but until then an Ontario provider is the fastest fix.
Is cost the main reason people leave wasp nests alone?
Not according to the available survey evidence. The national picture, which Ontario has no reason to escape: money is a real but not dominant obstacle, based on the 17% of New Zealand respondents citing cost in the Moths and Butterflies of New Zealand Trust's 2025 survey, an international attitude figure suggesting the bigger hurdles are knowing what to do and finding time. Ontario homeowners comparing quotes should ask each provider which of these patterns they see locally and why.
How common are wasp sightings?
Very common where wasps are established. What the research adds for Ontario: in the Moths and Butterflies of New Zealand Trust's opt-in survey of 1,055 individuals and 100 restoration groups in mid-2025, 67% reported frequent wasp sightings in the places they watch, which describes New Zealand habitats, not American homes. Local conditions in Ontario, California can differ from the survey population, so confirm the specifics with an on-site inspection.