Seaweed does not kill the mites, in fact it doesn't do anything to the mites at all. This is why you must use it on a regular basis BEFORE the mites show up. Mites show up, more or less, at about the same time each year. What seaweed does is it toughens up the "skin", the surface of the leaves, making it very difficult for the mites to attack the plant. The molasses just acts as a surfactant and it feeds beneficial microbial life on the leaf's surface. As I said, seaweed is NOT a pesticide or insecticide. You do the seaweed BEFORE and DURING the applications of the insecticide. By far the best organic insecticide or in this case miticide, is Neem Oil. As I am sure you know mites (spider mites) are just about impossible to eliminate once that have established a foothold on the plant. Both the seaweed and the Neem working together are the best (and only) way I have found to be effective against mites. Neem by itself does not control them and neither does liquid seaweed but working in tandem does work.
