Is it farther or further?
fumigant fu·mi·gant (fyōō'mĭ-gənt)
A chemical compound used in its gaseous state as a disinfectant.
any volatile, poisonous substance used to kill insects, nematodes, and other animals or plants that damage stored foods or seeds, human dwellings, clothing, and nursery stock. Soil fumigants are sprayed or spread over an area to be cultivated and are worked into the soil to control disease-causing fungi, nematodes, and weeds