Air pollution
damage is difficult to diagnose because many symptoms are similar to,
and aggravated by, those from other disorders and pests. Look-alike
disorders include aeration deficit, foliar pathogens, herbicide damage or other chemical phytotoxicity, nutrient disorders, sucking insects and mites, and water deficit.
Ozone damage
Needle tip necrosis on Monterey pine caused by ozone. Credit: Jack Kelly Clark, UC IPM
Ozone tip dieback and banding
Foliage damaged by ozone air pollution. Credit: Jack Kelly Clark, UC IPM
Ozone bleaching, bronzing
Chlorotic leaf spot on Japanese maple caused by ozone. Credit: Jack Kelly Clark, UC IPM
Ozone, chlorotic and necrotic spots
Sulfur dioxide damage
Necrotic, brown and white tips on the older needles of a pine tree due to sulfur dioxide air pollution. Credit: David A. Grantz, UC ANR Kearney Agricultural Research and Extension Center
Sulfur dioxide foliage browning
Foliage whitening from exposure to sulfur dioxide air pollution. Credit: Jack Kelly Clark, UC IPM
Sulfur dioxide whitening of leaves
Maladies that can resemble ozone damage
Yellow bands with dark fruiting bodies of a pine needle rust, Coleosporium sp., on Scots pine. Credit: Petr Kapitola, Central Institute for Supervising and Testing in Agriculture, Bugwood.org
Rust fungus, needle banding
Stippling caused by greenhouse thrips, Heliothrips haemorrhoidalis, feeding. Credit: Jack Kelly Clark, UC IPM
Thrips bleaching, bronzing
Rose leaves bleached and yellowed by twospotted spider mite, Tetranychus urticae, feeding on the underside of leaflets. Credit: Jack Kelly Clark, UC IPM
Spider mite bleaching, stippling
Elongate, while covers of male pine needle scales, Chionaspis pinifoliae. Each yellowish band on needles is where a scale previously fed. Credit: Jack Kelly Clark, UC IPM
Scale insects and feeding discoloration
Bleached foliage caused by lace bug, Corythucha sp., feeding. Credit: Jack Kelly Clark, UC IPM
Lace bug bleaching, stippling
Dieback and necrosis from anthracnose fungus, Discula fraxinea =Gloeosporium aridum, infecting ash leaves. Credit: Jack Kelly Clark, UC IPM
Anthracnose fungus dieback
Maladies that can resemble sulfur dioxide damage
Reddish pine needles due to root injury from road deicing salts applied during winter. Credit: USDA Forest Service - Rocky Mountain Region, Bugwood.org
Mineral or salt toxicity, foliage browning
Foliage whitening between veins from excess root exposure of grape to preemergence herbicide (simazine). Credit: Clyde L. Elmore
Herbicide damage, whitening of foliage
Lily-of-the-Nile foliage bleached white and yellowing from freeze damage. Credit: Jack Kelly Clark, UC IPM
Low temperature (freeze) bleaching
Leaf margin and tip necrosis and shoot dieback from water deficit (drought stress) due to insufficient soil moisture. Credit: Jack Kelly Clark, UC IPM
Water deficit, browning and dieback
Interveinal chlorosis on leaves of red maple, Acer rubrum, due to manganese deficiency. Credit: HortScience, Inc., Pleasanton, CA
Manganese deficiency, interveinal bleaching
Foliage damaged by mineral deficiency Credit: Jack Kelly Clark, UC IPM
Zinc deficiency, interveinal whitening
MORE INFORMATION
Abiotic Disorders of Landscape Plants, UC ANR
Air Pollution, UC IPM
Urban Trees and Ozone Formation , UC ANR
The pesticide information on this page may become out of date as products and active ingredients change or become unavailable. Some of the pesticides listed are only available for use by licensed pesticide applicators. No endorsements of named products are intended, nor is criticism implied of products not mentioned.
