$100 Above ground symptoms of this problem on deciduous trees are similar to other tree declines, but in addition, the trunk of the affected tree usually goes straight into the ground; there is no visible root flare.

GIRDLING ROOTS

$200 This is the main factor that determines whether a tree or shrub will suffer from cold temperature injury.

HOW QUICKLY THE TISSUE FREEZES

$300 This oft-used, systemic herbicide causes witches' brooms on woody plants if applied at sublethal dosages.

ROUNDUP

$400 Application (or misapplication) of a toxic chemical to a small portion of a tree's root system will cause branches in the crown to express symptoms in this pattern.

HELIX

$500 These are three clues that a particular disease is caused by a non-infectious agent.

MORE THAN ONE SPECIES INVOLVED

ALL MEMBERS OF A SINGLE SPECIES

RAPID ONSET OF SYMPTOMS

SYSTEMATIC PATTERN OF SYMPTOM DEVELOPMENT

$200 Phytophthora root rot is most likely to occur on rhododendrons planted in soil that is this.

HEAVY AND WET

$400 These symbiotic associations between plant roots and fungi play an important role in uptake of water and nutrients, especially phosphorus.

MYCORRHIZAE

$600 Fungi causing Armillaria root rot produce these structures in the soil to spread from diseased to healthy trees and to wait out tough times.

RHIZOMORPHS

$800 Many vascular diseases and root decay fungi spread to adjacent trees through these.

ROOT GRAFTS

$1000 This is the term given to the phenomenon of groundwater being absorbed by deep-growing striker roots during the night only to "leak out" of feeder roots and then be reabsorbed the following day.

HYDRAULIC LIFT

$100 This is one plant species notoriously sensitive to high pH soils.

PIN OAK

AZALEA

$200 Contemporary theory is that a lightning strike is more likely to kill trees with bark that is this.

DRY

$300 Longitudinal cracks in wood and bark of living trees can be caused by these two environmental events.

DROUGHT

FREEZING/THAWING

$400 Deicing salt injures plants in these three ways.

DAMAGE TO LEAVES WHEN TAKEN UP THROUGH SOIL

DAMAGE TO NEEDLES WHEN SPRAYED DIRECTLY ON FOLIAGE

TWIG DEATH DUE TO LOST COLD HARDINESS WHEN SPRAYED ON DECIDUOUS TWIGS

POTASSIUM DEFICIENCY

PHYSIOLGICAL DROUGHT

$500 These are three clues that a particular disease is caused by a non-infectious agent.

MORE THAT ONE SPECIES INVOLVED

ALL MEMBERS OF A SINGLE SPECIES INVOLVED

PATTERN TO SYMPTOM EXPRESSION

RAPID SYMPTOM EXPRESSION

ROOTS AND ROOT DISEASES

$200 This bacterial disease causes tumorous growths on roots and sometimes stems and branches of susceptible trees and shrubs.

CROWN GALL

$400 Circumstantial evidence indicates that girdling roots are most common on trees in this taxonomic group.

MAPLES

$600 Nematode diseases of trees and shrubs are apparently rare in the Northeast U.S. for this reason.

THEY ARE FROZEN OUT EACH WINTER

$800 These symbiotic associations between plant roots and fungi play an important role in uptake of water and nutrients, especially phosphorus.

MYCORRHIZAE

$1000 This is one fungicide selective for activity against fungi in the genus Phytophthora.

FOSETYL-AL OR MEFANOXAM

$100 Growth of a “turban” on a stump is suspected to be evidence of these.

ROOT GRAFTS

$200 Circumstantial evidence indicates that girdling roots are most common on trees in this taxonomic group.

MAPLES

$300 Vertically oriented roots that develop from the zone of rapid taper or from horizontal rope-like roots are called this.

STRIKER ROOTS

$400 Root wood differs from stem wood in these three ways.

ROOT WOOD DOESN’T PUT ON AN ANNUAL RING EACH YEAR

ROOT WOOD CELLS HAVE THINNER WALLS AND MORE PITS

ROOT WOOD IS ALWAYS DIFFUSE POROUS EVEN THOUGH STEM WOOD MIGHT BE RING POROUS

$500 Communal root systems, where they do exist, could offer these three advantages to a community of trees.

EXCHANGE OF WATER AND NUTRIENTS

MECHANICAL STABILITY

TRANSFER OF CHEMICALS TO DISCOURAGE PEST ATTACK

$100 This term is used to describe a condition where excess salt in the soil inhibits plant uptake of water, even when the soil moisture is adequate.

PHYSIOLOGICAL DROUGHT

$200 This achlorophyllous, yellow, vinelike plant parasitizes a wide array of seed plants.

DODDER

$300

$400 Application (or misapplication) of a toxic chemical to a small portion of a tree's root system will cause branches in the crown to express symptoms in this pattern.

SPIRAL OR HELIX

$500 These are three clues that a particular disease is caused by a non-infectious agent.

MORE THAN ONE SPECIES INVOLVED

ALL MEMBERS OF A SINGLE SPECIES

RAPID ONSET OF SYMPTOMS

SYSTEMATIC PATTERN OF SYMPTOM DEVELOPMENT

$100 Leafy mistletoe infections usually occur in the uppermost portions of tree crowns for this reason.

BIRDS TEND TO PERCH ON TREE TOPS AND THEY ARE MAIN VECTORS

$200 This term is used to describe plants like the mistletoes in which each individual plant is either male or female, but not both.

DIOECIOUS

$300 This sticky substance surrounds “fresh” mistletoe seeds and as it dries it glues the seeds to host branches until they germinate.

VISCIN

$ 400 Leafy mistletoes are usually found in this geographic region of the U.S.

SOUTH/SOUTHEAST

$ 500 Most taxa of dwarf mistletoes occur on these kinds of trees and in this part of North America.

CONIFERS IN THE WESTERN U.S.

Updated: July 7, 2001