Systemic Protection: How Systemic Pesticide Moves Through Plants to Complement Granular Insecticide Soil Barriers

 pesticide that travels with the plant, protecting every new leaf and every developing root—this is the promise of Systemic pesticide technology. Unlike contact products that remain where they are applied, systemic pesticides are absorbed by plants and translocated throughout their vascular systems. This movement provides protection against pests that never contact the leaf surface—stem borers, leaf miners, and root aphids. But systemics are not a standalone solution. They work best when combined with Granular insecticide products that create a chemical barrier in the soil. Together, systemic and granular technologies provide layered defense: granules kill soil pests before they reach the root; systemics kill any pest that feeds on the plant. Understanding how to integrate these tools is essential for modern pest management.

The Science of Systemic Movement

A Systemic pesticide must possess specific physicochemical properties to be absorbed and translocated:

• Water solubility – Sufficient to dissolve in soil water for root uptake (typically >500 mg/L)

• Lipophilicity – Balanced to cross root membranes (log P between 0 and 3)

• Metabolic stability – Resistant to rapid degradation by plant enzymes

• Phloem mobility – For downward movement to roots, the pesticide must load into phloem

Systemic insecticides fall into two mobility classes:

Xylem-mobile only – Move upward from roots to shoots through water-conducting tissue. These protect new growth but not roots. Examples: neonicotinoids (imidacloprid, clothianidin), fluopyram.

Amphimobile (phloem-mobile) – Move both upward and downward, protecting the entire plant. Examples: spirotetramat, some carbamates (aldicarb, oxamyl).

The Systemic pesticide market has grown rapidly, particularly for seed treatments and soil drenches. Over 80% of corn and soybean seeds in North America receive systemic insecticide seed treatments.

Systemic vs. Granular: Different but Complementary

While a Systemic pesticide moves inside the plant, a Granular insecticide remains in the soil. They are not alternatives; they are partners.

Systemic pesticide advantages:

• Protects new growth as plants develop

• Controls hidden pests (stem borers, leaf miners)

• No wash-off by rain or irrigation

• Minimal impact on beneficial insects (when applied as seed treatment)

Systemic pesticide limitations:

• Requires time to translocate (pests can feed before protection reaches them)

• May not reach all plant parts equally

• Some pests are naturally less susceptible to systemic chemistries

• Can contaminate nectar and pollen, affecting bees

Granular insecticide advantages:

• Immediate protection where applied

• Long residual in soil (weeks)

• No plant metabolism to degrade active ingredient

• Minimal pollinator exposure (unless dust-off occurs)

Granular insecticide limitations:

• Only protects the root zone

• Can be washed below root zone by heavy rain

• Bird toxicity concerns with some products

• Requires incorporation for best efficacy

The most effective programs use Systemic pesticide seed treatments for early-season protection and Granular insecticide in-furrow for soil pest control where systemic uptake is delayed.

Application Timing and Integration

Integrating systemic and granular products requires careful timing. A typical program for corn might include:

At planting:

• Systemic pesticide seed treatment (clothianidin, thiamethoxam) applied commercially

• Granular insecticide (tefluthrin, terbufos) applied in-furrow or T-band

Early season (VE-V3 growth stages):

• Systemic insecticide is translocating upward, protecting emerging foliage

• Granular insecticide protects roots and germinating seeds

Mid-season (V4-V8):

• Systemic insecticide reaches maximum concentration in leaves

• Granular insecticide continues soil protection (if persistent)

Late season (VT-R1):

• Systemic insecticide may have degraded; granular insecticide residual may be exhausted

• Foliar sprays may be needed for late-season pests

The Systemic pesticide market provides half-life data for each product in plant tissues. Fast-degrading systemics (e.g., imidacloprid) provide early-season protection only; persistent systemics (e.g., clothianidin) protect into mid-season.