Remarks:
It is a colourless to yellow-brown liquid with a characteristic unpleasant odour. It is generally prepared by combining O,O-dimethyl phosphorodithioate with diethyl maleate. It is soluble in most organic solvents except paraffin hydrocarbons and is practically insoluble in water. Malathion is readily decomposed by alkalies. The chemical works by binding to the enzyme acetylcholinesterase (AChE) at nerve endings, thus disrupting the neurotransmitter acetylcholine (ACh) and ultimately causing death.
Malathion is highly toxic to bees and other beneficial insects, aquatic invertebrates, and some species of fish, notably bluegill and largemouth bass. It is of moderate toxicity to birds.