including against fungus gnats. Related pyrethroid insectides have also been used. Pyrethrin compounds are known to occur in certain chrysanthemum flowers. Commercial greenhouses typically employ the insect growth regulator diflubenzuron for control of fungus gnats and their larvae. It is applied to infected soil and will kill fungus gnat larvae for 30–60 days from a single application. Its mechanism of action is to interfere with chitin production and deposition and it also triggers insect larvae to molt early without a properly formed exoskeleton, resulting in the death of the larvae. Although it is targeted at fungus gnat larvae, care should be taken in applying it as it is highly toxic to aquatic invertebrates. Diflubenzuron typically has no toxic effect on adults; only the larvae are affected. Biological control Various methods of controlling or eliminating fungus gnats with biological pest control have been developed. For example, Bacillus thuringiensis israelensis (BTI) is known to produce proteins that can kill fungus gnats larvae and some other insects like mosquitos. BTI is a naturally occurring bacteria that has been used for decades—the United States EPA reports that it has no toxicity to humans. Several dozen products containing BTI have been approved for residential, commercial, and agricultural use in the United States. The israelensis subspecies is suggested because other types of Bacillus thuriniensis (BT), such as those for controlling caterpillars, are ineffective at controlling fungus gnats. Steinernema nematodes have been used to control fungus gnats, including in combination with BTI. These nematodes, including the feltiae species, are parasites that can attack the larvae stage of fungus gnats. Mites of the species Stratiolaelaps scimitus (formerly known as "Hypoaspis miles") have also been shown to be effective at controlling fungus gnats . These scimitus mites are a natural predator that eat fugnat eggs and small larvae. Soaps, fly traps, and other methods Other methods for controlling fungus gnats include drenching the soil annually in an insecticidal soap. Hydrogen peroxide can be mixed with water and used to kill fungus gnat larvae in infected soil with a mixture of one part 3% hydrogen peroxide mixed with four parts water, then applied to the soil. Adults can be trapped with sticky traps made of yellow card stock or heavy paper coated in an adhesive since the adults are attracted to the color yellow. Since the gnats are weak fliers, fan-based traps as well as other fly-killing devices may be