Yes, Demon WP can be used on house plants.
Demon WP is not labeled to kill snakes. For snake control products, please click the link below.
http://www.domyownpestcontrol.com/snakes-c-179.html
When treating for roaches, we recommend using a bait, a liquid insecticide and an insect growth regulator (IGR). You are able to treat with all 3 of these products at the same time, just not on top of each other. For instance, our Roach Control Kit # 2 has all 3.
The Demon WP is for crack and crevice treatment around baseboards. Dilute 1 packet per gallon of water in a pump sprayer and apply in cracks and crevices where pests are seen, may harbor, or may enter the structure (corners, baseboards, and under and behind appliances) Do not spray on top of baits where bait will be used.
Per the product label under the First Aid table, follow the following procedures if Demon WP is inhaled or swallowed.
If swallowed:
If inhaled:
The label states to apply Demon WP Insecticide in calm weather when rain is not predicted for the next 24 hours will help to ensure that wind or rain does not blow or wash pesticide off the treatment area.
Demon WP Insecticide will create a barrier of treatment around and inside your home to treat and prevent Palmetto Bugs. Be sure to spray eaves, soffits, window frames, door frames, areas where cables, pipes or wires enter into the structure and any other crack, crevice or gap where insects can harbor.
You are able to apply Demon WP any time of year when you see activity or as a preventative treatment as long as the temperature is not at or below freezing when you are treating. Lady bugs are not specifically listed on the label, but Demon WP does treat for very common insects around the structure including spiders, cockroaches, boxelder bugs, fleas, and ants.
You should try not to mix more than you need of Demon WP Insecticide, but in the event that you do, you will pour any unused portion of solution right up against the foundation of the structure you are treating.