Amblyseius Andersoni is primarily used to prevent a spider mite infestation or as an out of season control rather than as a solution for a bad infestation.   It's an excellent product for catching the spider mites as they comes out of hibernation in the early spring.   The sachets contain a breeding colony of mites that crawl out slowly over a period of 4-6 weeks stopping an infestation from taking hold.  If you already have spider mites in large numbers please use Phytoseiulus first. These predatory mites are widely used in commercial glasshouses to control unwanted plant pests.  Amblyseius Andersoni is used to treat different species of Red Spider Mite (Tetranychus spp. and Panonychus spp.) Fuchsia Gall Mites, Pear Blister Mites, Rust Mites, Boxus Mite and Thrips, it can tolerate a wide range of high and low temperatures 6°C to 40°C, making it a great early season control.