Systemic

Definition

Acting on or distributed throughout the body rather than remaining localized at the point of entry or application. In arthropod physiology and pest management, describes substances—particularly pesticides, toxins, or pathogens—that are absorbed and translocated via circulatory or tissue systems to affect the organism globally.

Etymology

From Greek systēma (organized whole, body)

Example

Systemic insecticides such as neonicotinoids are taken up by plant vascular tissue and translocated to leaves, stems, and flowers, poisoning sap-feeding aphids or leafhoppers even when they feed on tissues distant from the original application site.

Related Terms

• contact insecticide
• Translocation
• Hemolymph
• neonicotinoid
• Fumigant
• residual toxicity

Usage Notes

Contrasts sharply with 'contact' (acting only at the surface touched) and 'stomach' (acting only after ingestion). In veterinary entomology, systemic antiparasitics given orally or by injection circulate through host blood to kill ticks, mites, or filarial worms. Some specialists reserve 'systemic' for circulatory distribution and use 'translocated' specifically for plant vascular movement, though the distinction often blurs in applied contexts.