It also controls numerous insect pests of field crops. Formulations include emulsifiable concentrates, wettable powders, ULV and flowable formulations and granules. Deltamethrin's mode of action is thought to be mainly central in action, or at least originate in higher nerve centers of the brain. Deltamethrin poisoning occurs through cuticular penetration or oral uptake. The susceptibility of insects is dependent on a variety of factors and can vary, as with many insecticides, according to the environmental conditions.
Flies are most susceptible to pyrethroid poisoning shortly before dawn.
Deltamethrin has very broad spectrum control. It is considered the most powerful of the synthetic pyrethroids. The signs of poisoning produced in rats by deltamethrin are not the same as those produced by other pyrethroids. Especially characteristic are rolling convulsions. The site of action is considered to be central with little or none of the peripheral component demonstrated for other pyrethroids.