WSU Extension

Hortsense

Cherry
 
Disease
Armillaria root rot 
Bacterial canker 
Brown rot blossom blight and fruit rot 
Crown gall 
Cytospora canker 
Dead bud 
Gumming (Gummosis) 
Leaf spot 
Little cherry 
Mottle leaf 
Necrotic rusty mottle 
Powdery mildew 
Prunus necrotic ringspot 
Shothole (Coryneum blight) 
Verticillium wilt 
Witches'-broom (Cherry leaf curl) 
Insect
Apple-and-thorn skeletonizer 
Black cherry aphid 
Brown marmorated stink bug 
Cherry bark tortrix 
Cherry fruit fly 
Cutworms and armyworms 
Earwigs 
Leafrollers 
Peachtree borer 
Pear slug (Cherry slug) 
San Jose scale 
Shothole borer 
Spider mites 
Spotted wing Drosophila (SWD) 



print version| pdf version| email url    
Caption: San Jose scale
Photo by: K. Grey
  
Cherry : San Jose scale
(revision date: 3/10/2017)


Biology
San Jose scale is an armored (hard) scale found on many deciduous trees and shrubs including apple, cherry, elm, maple, poplar, and willow. The scale insects are about 1/16" in diameter. The female is gray with a yellow spot in the center. The yellow crawlers are easily spread by wind, birds, or people. San Jose scale may be found on twigs, branches, leaves, and fruit. Heavily infested branches or entire trees may wilt and appear water-stressed. Severe infestations can cause twigs and branches to die back. Repeated infestations can kill trees. Infested fruit develop sunken spots surrounded by reddish areas. The scale overwinters as black immature scales on bark.
Management Options

Non-Chemical Management
  • Provide proper culture. Healthy plants are more tolerant of insect damage.
  • Prune and destroy localized infestations, when practical.
  • Natural predators and parasites help control scale populations, but may not prevent damage in severe infestations. Avoid use of broad-spectrum insecticides which kill beneficial insects.
  • By late April, begin monitoring for crawlers by using double-sided sticky tape.
Select non-chemical management options as your first choice!

Chemical Management

Control crawlers in mid-June or early July. Apply oil to overwintering stage just prior to bud swelling in early spring. Homeowners should not make foliar applications to trees over 10 ft tall. Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Lilly Miller Superior Type Spray Oil
    Active ingredient: oil/pet distillate  |  EPA reg no: 802-415
  • Ortho Volck Oil Spray Dormant Season Insect Killer Conc
    Active ingredient: oil/pet distillate  |  EPA reg no: 239-16
  • R-T-U Year-Round Spray Oil
    Active ingredient: oil/pet distillate  |  EPA reg no: 6218-78
  • Safer Brand Garden Defense Multi-Purpose Spray Conc [Organic]
    Active ingredient: clarified hydrophobic extract of neem oil  |  EPA reg no: 70051-2-42697
  • This list may not include all products registered for this use.
Images

+ Show larger images

 
Caption: San Jose scale
Photo by: K. Grey