the crops in which they are used. Once an active ingredient has achieved registration in major territories, it is in the supplier's interests to expand the market by seeking label approval for additional crops and pests, after field trials have been carried out to confirm the efficacy of the product in the new situation. Markets which themselves were too small to justify the expense of the original development and registration may now be attractive, particularly if economies of scale in the manufacture of the active ingredient have lowered its costs. In the case of λ-cyhalothrin, the current US label includes its use on alfalfa; canola; corn; rice; sorghum; cereals including barley, oats and wheat; vegetable crops including broccoli, cabbage and cauliflower; cotton; legumes including soybeans; lettuce; onion; peanuts; fruit including apples and pears; sugarcane; sunflower, and tobacco. The estimated annual use of λ-cyhalothrin in US agriculture is mapped by the US Geological Survey. While the original use was almost exclusively in cotton, the compound is now applied to many crops. In 2018, the latest date for which figures are available, were used. The equivalent map for γ-cyhalothrin is also available but its use was never high and is now declining. Malarial Vector Control Many insecticides, including DDT have been used to control mosquito species carrying the malaria parasite. The use of insecticide-treated bed nets has been shown to be an effective preventative measure. The World Health Organization (WHO) has approved λ-cyhalothrin (as its 2.5% capsule suspension formulation) for this use. Termite Control In 2003, the EPA approved the use of Impasse termite blocker containing λ-cyhalothrin to control termites around building foundations, especially where plumbing, electrical, and other utilities penetrated the concrete. Use in this way was intended to give long-term protection from the pest. FMC later introduced a similar product using γ-cyhalothrin Human safety Cyhalothrin is a restricted use pesticide. One consequence of this is that (in the USA) it is a violation of federal law to use the product in a manner inconsistent with its labelling and the labelling must be in possession of the user at the time of the application. It can be absorbed into the body by inhalation of dust or mist and by ingestion. It causes serious eye irritation. Symptoms of poisoning include burning sensation, convulsions, cough, laboured breathing, shortness of breath, sore throat. Skin exposure may also result in a sensation described as a