Friday Harbor's Seasonal Barrier Treatment Team

Most treatments stay effective around 21 days, which is why seasonal programs schedule on that cycle.

Both — barrier spray handles adults while larvicide treats standing water we can't drain. Effectiveness depends on more than just your own property, which is why we ask about neighboring water sources during the initial call.

Barrier product follows label guidelines for residential use — we'll note anything needing special handling.

Yes — we schedule timing a day or two before the event for maximum effect on the actual date.

Ponds usually need larvicide rather than barrier spray, since spray doesn't reach larvae developing in water. We can also advise on simple landscaping changes — trimming dense shrubs, thinning standing vegetation — that reduce resting habitat between visits.

A three-week cycle is typical, though heavier rain sometimes calls for tighter scheduling. We recommend a yard check after heavy rain, since new standing water shows up in unexpected places.