Wiktionary
phytotoxicity
n. 1 (context uncountable English) The condition of being phytotoxic 2 (context countable English) A measure of the extent to which something is phytotoxic
Wikipedia
Phytotoxicity
Phytotoxicity is a toxic effect by a compound on plant growth. Such damage may be caused by a wide variety of compounds, including trace metals, salinity, pesticides, phytotoxins or allelochemicals.