Arthropod pests

Root Aphids

Root-feeding aphids can be difficult to detect because much of the population lives below the canopy. Declining vigor alone is not diagnostic; confirmation requires root-zone inspection and identification of the organism.

What to look for

  • Small aphid-like insects on roots, container walls, or near drainage openings
  • Waxy residue or colonies in protected root-zone spaces
  • Winged forms appearing on monitoring cards during dispersal
  • Unexplained decline that coincides with confirmed root-zone insects

Important look-alikes

  • Fungus gnat larvae
  • Springtails and other harmless substrate arthropods
  • Root disease
  • Low oxygen, salinity, or irrigation stress

How to confirm

  • Inspect representative roots and container edges under magnification
  • Collect specimens for reliable identification
  • Compare symptomatic and apparently healthy plants
  • Use sticky cards only as supplemental evidence for winged forms

Management principles

  • Separate confirmed infested material
  • Avoid moving contaminated substrate or runoff between zones
  • Use an IPM plan matched to the identified pest and crop system
  • Track root-zone and aerial population signals over time

Prevention

  • Quarantine incoming rooted material
  • Sanitize reusable containers and work areas
  • Avoid cross-zone runoff
  • Maintain lot identity for propagation material

Visual study guide

  • Root aphid versus fungus gnat larva plate
  • Root-zone inspection diagram
  • Winged versus wingless aphid comparison
  • Contamination pathway map

Connected learning

Use the next piece of evidence

Move between reference material, measurement, field records, and whole-plant context instead of treating one page as the complete answer.