Permethrin is used:
as an insecticide
in agriculture, to protect crops (lethal for bees)
in agriculture, to kill livestock parasites
for industrial/domestic insect control
in the textile industry to prevent insect attack of woollen products
in aviation, the WHO, IHR and ICAO require arriving aircraft be disinsected prior to departure, descent or deplaning in certain countries
to treat head lice in humans
as an insect repellent or insect screen
in timber treatment
as a personal protective measure (cloth impregnant, used primarily for US military uniforms and mosquito nets)
in pet flea preventative collars or treatment
often in combination with piperonyl butoxide to enhance its effectiveness.
Wondering if it causes problems to the bees that hit the ground near the hives?