Pronunciation: tri- ' st ā -z ə
Function: noun
Etymology: Portuguese, literally, sadness, from Latin tristitia, from tristis sad
Date: circa 1902
: a highly infectious disease of citrus trees grafted on sour orange rootstocks that is caused by a single-stranded RNA virus (species Citrus tristeza virus of the genus Closterovirus, family Closteroviridae ) transmitted by aphids and that eventually causes death of the trees