Re: semi-OT: deterring critters in the obsy

Woody Schlom



Thanks for suggesting pyrethrin based products.  I hadn’t thought of that.  I’ve used them on camping gear and clothing with success against mosquitos and the like.  You spray the stuff onto fabrics (clothes, tents, etc. in my case) and when it’s dry, it lasts at least 6 months – even through several washing machine cycles.


According to what I’ve read, it’s poisonous to everything (including humans) while wet after application, but only harms (kills) insects when dry.  And it kills on contact somehow – even months later.


I’m thinking that it should indeed work in an observatory – sprayed onto covers, walls, ceiling, floor.  BUT you have to be very careful spraying the stuff – as in cover yourself in a complete disposable painter’s outfit AND wear a fancy chemical rated respirator.  I’d think one specifically designed and rated for spray painting should work well.




From: [] On Behalf Of Joseph Beyer
Sent: Friday, September 17, 2021 1:46 PM
Subject: Re: [ap-gto] semi-OT: deterring critters in the obsy


Some of the pyrethrin-based insecticides, which tend to be less toxic to mammals have sustained activity.  In particular there are sprays or formulations that claim to give one to several months of activity.  I use an Ortho product that is called a perimeter defense that is stated to provide 6 months of activity.  After drying it is essentially odorless and from what I've observed seems to be quite effective.  I have a small weather station in my yard and the spiders find it very inviting.  Once or twice a year I'll open it up and wipe a thin coating of the perimeter defense spray inside and it helps a lot in keeping the critters out.

I think the pyrethrin-based insecticides that are used for subterranean termites are even more prolonged in activity since they're injected into the ground around structures.


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