Which type of insecticide is limited in applications primarily to impervious surfaces for controlling accidental invaders?

Pyrethroid insecticides are designed for effective use on impervious surfaces, making them particularly suitable for controlling accidental invaders like ants, cockroaches, and other pests that may enter buildings. These chemicals work by disrupting the nervous system of the insects, leading to quick knockdown and death upon contact.

The application on impervious surfaces allows for targeted treatments in areas where pests are likely to travel or congregate, such as foundations, walkways, and other non-porous surfaces. This method minimizes the risk of chemical migration into soil or water systems, aligning with safety guidelines for pest management.

Other types of insecticides listed have varying applications and may not be exclusively tailored to impervious surfaces. For example, neonicotinoids can be effective in plants but might not be as readily effective on hard surfaces. Organophosphates have broader applications but are subject to restrictions due to toxicity concerns. Insect growth regulators focus on disrupting development stages rather than immediate control, which may not suit scenarios involving rapid invasions by adult pests. Hence, the specificity of pyrethroids to impervious surfaces makes them the most suitable choice for this scenario.