San Jose Scale on Peach
Return to Insect Pests
San Jose scale (Quadraspidiotus perniciosus) are tiny (1⁄20 of an inch) gray sucking insects that reside underneath a waxy covering. Scale coverings are flat, circular in shape, and have concentric rings with a tiny knob in the center. Crawlers (immature stage), which are yellow and resemble spider mites, are 1⁄200 inch in size and only visible with a hand lens. Red flecking on fruit at harvest or under bark on new growth is due to toxic saliva injections. San Jose scale can kill limbs or entire trees.
San Jose scale on surface of branch.
(Photo: Ric Bessin, University of Kentucky)
Bark removed to show damage to wood tissue.
(Photo: Ric Bessin, University of Kentucky)
Damage to ripening fruit.
(Photo: Charlie Graham, Noble Foundation)
Management:
- Apply dormant oil.
- Scout to determine population levels: attach a piece of black tape (sticky side out) on an infested limb to detect crawlers.
- Apply insecticides to target crawler stage either at pre-bloom or early summer.
