WSU Extension

Hortsense

Holly
 
Disease
Boron deficiency 
Green algae 
Phytophthora leaf & twig blight 
Red leaf spotting 
Insect
Brown soft scale 
Cottony camellia scale 
Holly bud moth 
Holly leafminer 
Lecanium scale 
Orange tortrix 



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Caption: Orange tortrix larva on raspberry
Photo by: R. LaLone
  
Holly : Orange tortrix
(revision date: 3/10/2017)


Biology
The larval stage of the orange tortrix is a leafrolling caterpillar. The larvae are tan to pale green with tan heads and about 1/2" long at maturity. The feeding caterpillars typically roll or twist individual leaves or clusters of leaves at shoot tips and tie them into loose nests with webbing. The larvae are very active when disturbed. The orange tortrix is a pest of many woody plants, including fruit trees and several common landscape plants such as holly, rose, euonymus, oak, and willow.
Management Options


Non-Chemical Management
  • Hand-pick and destroy rolled leaves, or pinch to kill caterpillars inside.
  • Prune out webbing, if desired.
  • Provide proper culture. Healthy plants can easily tolerate some defoliation.
Select non-chemical management options as your first choice!

Chemical Management

Apply when caterpillars or damage is first noticed. Sevin (carbaryl) is particularly dangerous to honeybees since it does not immediately kill them. They return to the hive with the poison and distribute it within. Therefore avoid carbaryl if at all possible if there is a chance of pesticide drifting onto nearby blooming plants. Bacillus thuringiensis (Bt) will control leafrollers only if they are actively feeding. Use a spreader-sticker with liquid Bt formulations. 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 Malathion Insect Control Conc
    Active ingredient: malathion  |  EPA reg no: 4-99
  • GardenTech Sevin Conc Bug Killer
    Active ingredient: carbaryl  |  EPA reg no: 264-334-71004
  • Hi-Yield 55% Malathion Spray
    Active ingredient: malathion  |  EPA reg no: 7401-10-34911
  • Safer Brand Caterpillar Killer/Trees, Shrubs, & Vegetables Conc
    Active ingredient: Bacillus thuringiensis subsp. kurstaki  |  EPA reg no: 42697-23
  • This list may not include all products registered for this use.
Images

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Caption: Orange tortrix larva on raspberry
Photo by: R. LaLone