UPDATE: The spraying effort began Wednesday morning, April 20th.

There is a “reproducing group” of destructive gypsy moths loose on a corner of Capitol Hill and the state is preparing plans for eradication. Officials say the organic pesticide Btk is not toxic to humans but recommend minimizing exposure. If you’re planning a short vacation away from the Miller Park neighborhood when the state’s “small airplane” drops its payload, you had better keep your bags packed.

A Washington State Department of Agriculture spokesperson tells CHS that the spraying process is highly weather dependent and with the current warm spell over this area of Washington, the state may get an itchy trigger finger for the start of the project currently targeting the first week of May:

Current models project that treatments for the Vancouver area will begin between April 22 – 25. Vancouver treatments will be conducted by helicopter.

We anticipate that the remaining sites further north (Seattle, Tacoma, Kent, Gig Harbor, Nisqually, and Lacey) will begin treatments the first week of May. These areas will be treated by a small airplane.

Reminder: All treatment times are highly dependent on the weather. Should we have warmer or colder weather than anticipated, treatment times could start earlier or later. To receive notifications when treatments actually occur, sign up for our alerts via e-mail, text, or robo call.

The spokesperson suggests if you’re concerned about the spraying, you should sign up for the alerts as soon as possible just in case the timetable gets moved up.

CHS first reported on the eradication plans in January and the presence of 22 moths found last year, six in 2014 and one each found in 2013 and 2012. State officials also found eight egg masses in the area last year, each of which can mean from 100-1,500 eggs.

Officials came to Miller Community Center earlier this year to discuss the spraying plans with residents.

The state has been treating for gypsy moths since 1979. As of last year, they had conducted 93 eradication efforts across the state, including one here in 2006. Last year, the department deployed about 16,000 traps to attempt to detect gypsy moths across the state.

CHS wrote here about the differences between the moths, the history behind the infestation and why they’re such nasty neighbors. Gypsy moths caterpillars are incredibly voracious and not terribly picking, having been documented eating over 300 species of trees and shrubs.

In winter, the moths are in egg form. They hatch and the caterpillars are active from spring into early summer when they will go through their chrysalis phase before becoming adult moths. The adults live only for a couple weeks, during which time they do not eat, only reproduce. The spraying itself will consist of three to five treatments. A spokesperson said the ideal number is three, but sometimes circumstances such as rain shortly after a spraying can mean that areas will need to be treated again.

Btk is a bacteria believed to be very low risk to humans and animals other than moths and their close relatives though some disagree.

So, how did the destructive moths end up on Capitol Hill? The most likely explanation is someone moving here from out-of-state — likely from one of the 19 states in the mid-Atlantic, New England and upper Midwest where gypsy moths are well established. Females will lay their eggs on a flat surface, and the moths stay in that egg state for about nine months. “European gypsy moths usually come from people moving here, or bringing items from other states,” Karla Salp, community outreach and environmental education specialist for the Department of Agriculture told CHS earlier this year.