Predatory mites are adult mites that hunt and kill pest mites, particularly the common spider mite. They are shipped live and ready to destroy pests, controlling pest populations without the need for chemical pesticides. Best used at the first sign of an infestation, only 2 to 5 adults per plant or 500-2,000 per tree are necessary. Each container includes 2,000 live adults. Gardeners simply mail in the postcards or register online to have their insect orders shipped to their doors at no extra cost.