systemic

(translocated) Describing a chemical that is absorbed by a plant and transported throughout the tissues. Systemic fungicides and insecticides are applied to render plant tissues toxic to fungi or insects. Their effects are longer lasting than those of contact pesticides. Systemic herbicides, such as 2,4-D, 2,4,5-T, and MCPA, are used as selective weedkillers, killing most broad-leaved plants but leaving grasses and cereals unaffected. Such herbicides are also used to kill deeply rooted weeds.