Pages 293-308 in the Montana Master Gardener Handbook Slides provided by Linnea G. Skoglund, Ph.D. MSU Schutter Diagnostic Lab
Top 5 Tree Problems
#5 Cause of Tree Problems people doing crazy things
#4 Cause of Tree Problems herbicides
#3 Cause of Tree Problems weather
Tamla Blunt, CSU, 2009
#2 Cause of Tree Problems wrong tree for the location
Blue Spruce - Picea pungens
distribution precipitation
#1 Cause of Tree Problems Fungi? Bacteria? a Viruses?
#1 Cause of Tree Problems insufficient water
Water Placement
Measuring water
Checking Soil Moisture
STOP! Think about what causing the Problem?
Conditions Necessary for Disease Susceptible Host DISEASE Signs and symptoms No Disease No Disease No Disease Favorable Environment Pathogen
Needle Cast and Tip/Shoot Blight Diseases Diagnosis Needle casts and blight look- Appearance of tree alikes Timing of needle shed Winter injury Age of needles affected Frost Fruiting structures Drought Don t forget the cones and Dog urine fallen needles! Mite and insect damage Vole damge
Flecks, Spots, Bands on Needles (symptoms)
Fruiting Structures (signs)
Fungus/Disease Primary Hosts Name Scots pine, ponderosa pine Lophodermium Needle Cast Diseases of Conifers Infection Period/Fruiting Bodies Symptoms Needles Shed Timing Mid late spring Scots pine ponderosa pine Lophodermium Late summer - early fall Winter- early spring Mid-late spring Ponderosa, lodgepole pines Ponderosa, Austrian, mugo pines Elytroderma Dothistroma (Mycosphaerella) Small, gray or black, football-shaped hysterothecia visible to the naked eye. When mature, these protrude slightly, and the epidermis ruptures to form a slit. Mid - late summer Long black slit in epidermis near needle base Spring Black dots erupting thru epidermis in bands Lodgepole pine, limber pine Lophodermella Late spring - early summer Small depressions in leaf surface Douglas fir Rhabdocline Late spring summer Yellow and reddish-brown spots on the needles, some of which may have yellow margins. Eventually, the entire needle will turn yellow, then reddish brown. Early spring Needles red-brown at tips, base remain green, witches brooms Late summer - early fall Distinct red transverse banding on tan needles Early late spring Dead, reddish-brown, then straw colored. Late summer - early fall 12-20 months after infection Summer Summer Summer Tan slits on underside of needles Douglas fir Swiss Needle cast Late spring early summer Fir Lirula Summer Spruce Rhizosphaera/ Stigmina The tiny black dots emerge through the stomata in rows on the underside on either side of the midrib. Dark, elongate pycnidia down center of lower surface of needles. Brown line on upper surface. Pustule like. Spring Fall Spruce Sudden Needle Drop Unknown Black dots in stomata in rows Black specks (perithecia) on twigs Yellow lesions followed by purple-brown spots and bands Within a year New needles become yellow overall although they occasionally turn brown general chlorosis or red-brown tips Spring Needles become pale and patchy green and slowly turn brown. Late winter-early spring Yellow to reddish-purple to brown Unknown (late winter early spring) Older needles are affected. Turn yellow to reddishpurple to brown similar to other spruce diseases 1-3 years after infection 2 years after infection Late summer - Fall Unknown (late summer early fall) All species Seasonal Needle Cast None Fall Inner most needles suddenly turn brown. Needle retention depends on species and environment. Fall
Spruce Rhizosphaera Needle Cast R k lkh ffii R. kalkhoffii Tree looks thin and bare Year-old needles turn purplish brown Bottom needles drop in late summer while current year remain Spread upward and around tree Pycnidia in rows in stomata in late winter/early spring
Seasonal Needle Cast
Needle Cast Management Proper site selection p Optimum plant care Plant healthy trees Good planting techniques Good air flow in canopy Fungicides not usually necessary in Montana
Fungus/Disease Name Primary Hosts Symptoms Phomopsis Juniper Spring and summer Tip Blights/Shoot Blights of Conifers Tips of new growth die back becoming tan to brown. Grayish band/canker at base of dead twig. Comments Mature foliage resistant Similar to dog urine damage, winter injury, frost damage, and drought Pycnidia at base/canker Kabatina Juniper Early spring Tips of year old twigs turn brown in spring as new growth begins. Grayish lesion/canker at base of discolored tissue. Dieback of older twigs when girdled. Infects through wounds Easy to confuse with winter injury. Sirococcus Sudden Needle Drop Spruce, mugo and other pines, Douglas fir Acervuli found in dead tissue Apparent from June August Shoot tips wither, droop and die. May form shepherd s crook. Affected branches scattered in tree. Needles become chlorotic, die, turn reddish-brown, and are shed. Pycnidia found on killed stems and base of killed needles and cone scales Damage on large, established trees is usually confined to lower branches and does not significantly impact their overall health. Looks like frost, drought and other environmental damage. Spruce Unknown Similar to Sirococcus, Cytospora and Rhizosphaera Needles become chlorotic, die, turn reddish-brown, and are shed. Pycnidia found on killed stems and base of killed needles and cone scales Sphaeropsis (Dipoldia) Pines Symptoms first seen early midsummer. Stunting and browning of current-year needles and shoots. Lower branches first. Occurs on older trees : 25-30 yrs old. Repeated infection leads to death of branches and general decline of tree. Black pycnidia on needles, shoots and cones.
Phomopsis Tip Blight Phomopsis juniperivora Phomopsis juniperivora Tip blight in summer Grayish band/canker at base of dead part Pycnidia at base/canker Mature foliage resistant
Kabatina Tip Blight Kabatina juniperi Kabatina juniperi Attacks year old tissue Year old twigs killed in spring Grayish lesion/canker at base of discolored tissue Acervuli found in dead tissue Overwinters on twigs Dieback of older twigs when girdled
Sirococcus Tip Blight Sirococcus conigenus or strobilinus Spruce, mugo and other pines, Douglas fir Attacks new, succulent tissue Shoot tips wither, droop and die Affected branches scattered Pycnidia found on killed stems and base of killed needles late summer early fall Fungicides may help
Juniper Tip Blight Management Prune out dead material when plants are dry Water in early morning so foliage dries Avoid over-watering and planting in poorly drained or shaded locations Reduce fertilizer (N) Don t pile snow on bushes Fungicides not practical for homeowners
Canker Diseases
Cytospora Canker
Cytospora Canker
Cytospora Canker Management Cut out affected limbs Fertilize to strengthen trees and promote growth Balanced watering Symptoms on spruce can be abiotic Drought Frost Animal damage Fungicides not shown to be effective!
Leaf Diseases Owners (overly) sensitive 5% damage Redundancy in trees Up to 50% more leaves than needed Other things look like disease esp. leaf miners and abiotic
Blights, Spots, Rusts Favored by cool (60 75F) and moist conditions and high fertility (N) Over winter in host plant, fallen leaves/needles and fruit, alternate t hosts, weed hosts Spread by rain splash, insects, pruners, wind and air currents
Marssonina leaf blight Marssonina spp Marssonina spp.
Septoria leaf spot p p S. musiva
Anthracnose Apiognomonia spp.
Shoot Blights Caused by fungi and bacteria and look like frost.
Rusts
Juniper Hawthorn (cedar-apple) rust
Leaf rusts
Blights, Spots, Rusts Management Prune to remove infected tissue and reduce inoculum. This also opens up the plant for air circulation and drier leaves. Remove fallen leaves and fruit Remove alternate hosts Manage water Fungicides may help
Fire blight Erwinia amylovora Apple, pear, mountain ash, raspberry, pyracantha, hawthorn, cotoneaster - >130 species in rose family
Fire blight Integrated Control No cure! Pruning remove inoculum Reduce nitrogen Antibiotics Timing critical Require multiple applications Use 2 or more products Resistance management King bloom Full bloom Petal fall
Fire blight Chemical Control Streptomycin >90% control AgriStrep and Firewall Oxytetracycline >70% control Mycoshield and Fireline Copper 60% control Kocide 3000 cost and phytotoxicity From trials in Oregon and Washington
Thanks! Questions?