WSU Extension

Hortsense

Lilac
 
Disease
Bacterial blight 
Powdery mildew 
Insect
Lilac borer 
Lilac leafminer 
Oystershell scale 



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Caption: Lilac leafminer
Photo by: R.S. Byther
  
Lilac : Lilac leafminer
(revision date: 3/8/2016)


Biology
Leafminers feed by removing green tissue from between the upper and lower surfaces of the leaves. Symptoms of feeding by the green larvae include large brown blotches which may distort the leaves. The adult lilac leafminer is a small brown moth. The lilac leafminer may also infest privet.
Management Options


Non-Chemical Management
  • Pinch, or pick and destroy, infested leaves to kill larvae.
  • Natural predators may help control populations. Encourage predators such as green lacewings and spiders.
Select non-chemical management options as your first choice!

Chemical Management

If you choose to use a pesticide, apply when mined blotches are first noticed or at least before leaves fall. Repeat as necessary (do not make more than one application per year if using Bayer Advanced Garden Tree & Shrub Insect Control Conc). 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.
  • Bonide Captain Jack's Deadbug Brew RTSpray [Organic]
    Active ingredient: spinosad  |  EPA reg no: 4-471
  • Bonide Systemic Insect Control
    Active ingredient: acephate  |  EPA reg no: 239-2461-4
  • ferti-lome Broad Spectrum Insecticide
    Active ingredient: bifenthrin  |  EPA reg no: 53883-228-7401
  • This list may not include all products registered for this use.
Images

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Caption: Lilac leafminer
Photo by: R.S. Byther