Biological pest control predatory midge "Feltiella acarisuga", and a ladybird "Stethorus punctillum". The bug "Orius insidiosus" has been successfully used against the two-spotted spider mite and the western flower thrips ("Frankliniella occidentalis"). Predators including "Cactoblastis cactorum" (mentioned above) can also be used to destroy invasive plant species. As another example, the poison hemlock moth ("Agonopterix alstroemeriana)" can be used to control poison hemlock ("Conium maculatum"). During its larval stage, the moth strictly consumes its host plant, poison hemlock, and can exist at hundreds of larvae per individual host plant, destroying large swathes of the hemlock. Not all biological control agents are directed at
Poison drilling rigs). Plant-based contact irritants, such as that possessed by poison ivy or poison oak, are often classed as allergens rather than poisons; the effect of an allergen being not a poison as such, but to turn the body's natural defenses against itself. Poison can also enter the body through the teeth (in the controversial case of dental malpractice), faulty medical implants, or by injection (which is the basis of lethal injection in the context of capital punishment). In 2013, 3.3 million cases of unintentional human poisonings occurred. This resulted in 98,000 deaths worldwide, down from 120,000 deaths in 1990.