An exposure to a chemical that has the role of nematicide nematicide exposure An exposure to a chemical that has the role of antimicrobial agent antimicrobial agent exposure An exposure to a chemical that has the role of cytokinin cytokinin exposure An exposure to a chemical that has the role of auxin auxin exposure An exposure to a chemical that has the role of fertilizer fertilizer exposure An exposure to a chemical that has the role of growth hormone growth hormone exposure An exposure to a chemical that has the role of pesticide pesticide exposure An exposure to a chemical that has the role of herbicide herbicide exposure An exposure to a chemical that has the role of micronutrient micronutrient exposure An exposure to a chemical that has the role of fungicide fungicide exposure An exposure to a chemical that has the role of insecticide insecticide exposure