Diagnosing g Tree and Shrub Injuries

Diagnosing g Tree and Shrub Injuries Compiled by: Mike Rose, Ward County Extension Agent 9-05-08

Tree Problems Mites Insects Diseases Environmental Critters Other

Diagnosing Tree and Shrub Injuries Red numbers in bottom of slide indicate page that describes the problem

Mites and Insects

Spruce Spider Mite Spruce, arborvitae, juniper, and pine Injury more evident under hot and dry conditions Tap Test Management Wash off Miticides 25

Mite Damage on Deciduous Trees

Galls Galls are abnormal growths of plant tissue caused by a wound, infection by a microorganism, or the feeding and egglaying activity of certain insects and mites Once galls start, formation is largely irreversible Galls rarely cause serious damage 21

Poplar Bud Gall Mite Gall are irregular,lumpy,solid mass of plant tissue Young galls are greenish, older galls are brown Mostly aesthetic Branches a c may become e crooked or stunted 23

23 Poplar Petiole Gall

Galls Maple bladder gall Spindle gall 20

Ash Flower Gall Mite Galls form on male flowers of green ash trees Galls start out green, then turn brown May remain attached to the tree for several years Generally does not affect health of the tree 12

Oystershell Scale Feeds by sucking plant sap Found on many broadleaved trees and shrubs, especially cotoneaster Can cause dieback Dormant oil Insecticide on the crawlers in early July 22

Pine Needle Scale Resembles drops of white paint Scales suck juices from the needles Conifers are the host Dormant oil or use an insecticide in late May and treat again in ten days Do not use dormant oils on blue spruce 23

European Elm Scale Sap-sucking can cause stunted, chlorotic foliage Branch dieback Often associated with black sooty mold Treat with dormant oil Treat with insecticide in late June or early July 18

European Elm Scale scale Sooty mold 18 & 44

Ash Plant Bugs Feeds by sucking plant sap Two generations per year Extremely common, but generally not treated 13

Aphids Many conifers and broadleaved trees and shrubs Feeds by sucking plant sap Can deform plant leaves and shoots and reduce growth Sooty mold Beneficial predators 12

Aphids Ladybug beetle

Cottony Ash Psyllid New to the area Feeds on black ash and manchurian ash Feeding causes leaflets to become shriveled and discolored Insecticides must be applied early in nymph stage Bayer Advanced Tree and Shrub

Psyllid Feeding Damage Adults Nymphal Castings Dave Nelson, NDDA Dave Nelson, NDDA Adults can be seen on top of this highly distorted foliage, along with many nymphal castings from previous molts. Psyllid nymphs can be found in the cottony material (produced by the feeding insect) on the underside of the curled leaf.

Cottony Maple Scale Scale can cause twig dieback severe infestations can kill major limbs Secretes honeydew Major problem in eastern North Dakota Bayer Advanced Tree and Shrub

Yellowheaded Spruce Sawfly Spruce Overwinter as mature larvae, adults emerge as spruce buds expand, eggs laid in current year s needles Mostly in northern counties Larvae usually first appear in mid-june More common in rural areas 27

Yellowheaded Spruce Sawfly

Yellowheaded Spruce Sawfly Risk Map

Fall Webworm Many broadleaf trees Mostly an aesthetic concern Management Prune out Insecticide treatments Open nests up 19

Cankerworms (Spring and Fall) Feed on a variety of hardwoods Loopers Managementt Sticky material Early September (Fall) Mid-March (Spring) Bt and other insecticides

Poplar Borer Aspen, cottonwood, poplar, willow One to three year life cycle Management Maintain tree health Remove brood trees Insecticide treatments

Ash Borer Infest all species of ash Trees under stress more susceptible Red-headed ash borer and ash/lilac borer present in the state Bayer Advanced Tree and Shrub is a control option 13 Sawdust (frass) Borer hole

Emerald Ash borer Devastating all species ash trees in Great Lakes area Not yet found in North Dakota

Apple Maggot Sunken dimple with a small brown trail through h the fruit Fruits drop prematurely Treat in late June and continue every 7-10 days through August Pick up fallen fruit

Plum Curculio Injury is a sunken pit A scar will develop at the bottom of the pit Site puncture will stop growing giving i the fruit a knotty appearance Fruit does not necessarily drop

Bronze Birch Borer Dieback on upper- most branches common Adults can only be controlled in late spring Use of Bayer Advanced Tree and shrub is a control option Birch in poor vigor more susceptible Plant varieties that show some resistance 14

Bronze Birch Borer D shaped exit hole

Prairie Tent Caterpillar Larvae feed outside web making control easy Most common species Forest t Tent Caterpillar Do not have webs Travel as army Turtle Mts. 24 & 19

Prairie Tent Caterpillar

Forest Tent Caterpillar Defoliation

The Overuse of Insecticides Major problem: treating trees that need not be treated Treating trees that are not infested with a serious insect problem can cause greater problems in the future because beneficial predators and parasites are killed.

Diseases

Apple Scab Apples, crabapples, mountain-ash Problem during prolonged wet weather Leaf and fruit infections Management 33 Clean up plant debris Promote t good air circulation Protectant fungicides Use resistant cultivars

Ash Anthracnose Green ash and other ash species Defoliation following prolonged wet period in the spring Protectant fungicides 33

Rhizosphaera Needlecast Spruce (especially Colorado) Promoted by prolonged wet periods Management Promote good air circulation Two years of fungicide treatments 43

Infected Needle Uninfected Needle

Powdery Mildew Damage is often aesthetic Premature defoliation More common is shaded d areas Found on many trees,vegetables, t and grasses 42

Oak Leaf Blister Appear as wrinkled, raised bulges on the upper leaf surface Bulges lighter in color More common on the lower portion of the tree Rarely causes substantial damage to established trees Fungicide id must be applied prior to bud break 42

Fire blight 39 Apple, cotoneaster, crabapple, mountain ash, hawthorn Caused by bacteria Management Use resistant plants Avoid succulent growth Pruning (with sanitation) Chemicals

Black Knot Chokecherry, plum, and other stone fruits May kill branches Management Remove knots Fungicidesg Manage neighboring plants 34

Black Knot More damaging when occurs on trunk

Cytospora Canker of Spruce Spruce (especially Colorado and Norway) Usually begins in lower crown Management Remove infected branches Maintain tree health 36

Cytospora Canker Branch Dieback Whitish, Resin Patches

Dutch Elm Disease Elms (all species) Transmitted by elm bark beetles and through root grafts Management Sanitation Preventative t ti fungicide injections Resistant elm cultivars 37

Dutch Elm Disease

Cedar-Apple Rust Orange gelatinous spore-bearing structure t on juniper Yellow-orange lesions on apple Remove one of the hosts Remove galls 36

Rust Yellow to orange lesions Remove alternate host Fungicides i id are protectants - must be applied on a regular interval prior to onset of the disease

Plum Pockets Fruit distorted and enlarged Infected shoots are thickened and deformed Infected parts of the plant should be removed Lime sulfur application in the spring normal 42

normal Plum Pockets

Septoria Leaf Spot Premature leaf drop Disease over-winters on fallen leaves Plant varieties that are resistant it t Can weaken tree and make it more susceptible to canker diseases and early death 44

Sooty Mold 44 Grow on excrement of certain sucking insects such as aphids and scales Sooty mold does not penetrate the leaf or bark tissues Can be associated with European uop Elm Scale

Sooty Mold scale Sooty mold

Western Gall Rust Galls increase in size each year Branches may die above galls Branches may break at point of infection Remove galls Do not plant new pine trees within 500 yds. Of infected trees

Environmental Damage

Winter Injury Reflection of sun off the snow Needles run short of moisture Rapid fluctuations ti in temperatures - not enough time for plants to harden off Can t t make brown needles green 47

Winter Injury Application of antidesiccant in late fall and very early spring may help Apply miracid in late spring

Winter Injury Snow line Anchor rope

Sunscald

Leaf Scorch Stress on the plant poor soil flood or drought nearby excavation very high temperatures recently yplanted Lack of water and/or oxygen to the leaves 38

Iron Chlorosis Low availability of iron to the plant Leaves are pale yellow-green Commonly l the veins will remain green Iron chelate may provide temporary relief 39

Iron Chlorosis

Heat-Moisture Stress Note the uniform dying back of the needles!

Critter Damage

Mouse Damage Damage typically occurs under the snowline Keep excess residue from around the trees Damage more prevalent when there is early snowfall

Deer Damage

Porcupine Damage Scotch pine very susceptible Larch, aspen, willow, and cottonwood also susceptible Squirrel and rabbit repellents may help Open-grown trees more susceptible