Certified Arborist Test Tree Diagnosis and Treatment 3

Question 1

What are the key diagnostic features that distinguish bacterial leaf scorch (BLS) from drought stress or other leaf scorch conditions in oaks and elms?

Accepted Answer

BLS causes marginal leaf browning that progresses inward with a distinct yellow or reddish band separating living and dead tissue, appears in mid to late summer, and recurs annually with greater severity

Answer

BLS causes spotting with yellow halos, unlike drought scorch which affects leaf margins without halos

Answer

BLS causes premature fall color change beginning in early August, while drought scorch turns leaves tan-brown uniformly

Answer

BLS causes gall formation on leaf surfaces along with marginal browning, distinguishing it from abiotic scorch

Question 2

What are the primary differences between contact insecticides and systemic insecticides in arboricultural treatments, and when is each type preferred?

Accepted Answer

Contact insecticides kill insects directly upon contact but have no plant-protective residue; systemic insecticides are absorbed and translocated within the plant, providing internal protection against feeding insects

Answer

Contact insecticides work on soil insects; systemic insecticides work on foliar insects — preference depends on pest location

Answer

Contact insecticides are organic; systemic insecticides are synthetic — organic preference drives the choice

Answer

Contact insecticides treat soil pathogens; systemic insecticides treat wood decay fungi — pest type determines selection

Question 3

How does the integrated pest management (IPM) approach differ from traditional pest management, and what are the four core IPM tactics?

Accepted Answer

IPM is a decision-making framework that uses monitoring and economic/aesthetic thresholds to select the least disruptive effective combination of cultural, biological, mechanical, and chemical tactics

Answer

IPM eliminates all pesticide use in favor of biological controls; traditional management relies only on pesticides

Answer

IPM focuses exclusively on native plants and native pests; traditional management handles introduced species

Answer

IPM is a regulatory compliance program required by the EPA; traditional management is voluntary

Question 4

What is phytophthora root rot, what conditions favor it, and how should affected trees be managed?

Accepted Answer

A soilborne water mold disease favored by saturated, poorly drained soils — managed by improving drainage, reducing irrigation, and applying phosphonate fungicides

Answer

A foliar fungal disease favored by dry conditions — managed with protective copper fungicide sprays in summer

Answer

A vascular wilt disease spread by contaminated pruning tools — managed with tool sanitation and preventive fungicide injection

Answer

A bark disease favored by freeze-thaw cycles — managed with dormant oil and wound sealant applications

Question 5

What are the symptoms of emerald ash borer (EAB) infestation, and at what stage of infestation are symptoms typically first visible?

Accepted Answer

Symptoms (canopy dieback, D-shaped exit holes, serpentine galleries, bark splitting, epicormic sprouting) typically appear 1-3 years after initial infestation, when larval populations are significant enough to disrupt vascular transport

Answer

Initial infestation is visible immediately as adult feeding notches on leaf margins — symptom detection is possible from year one

Answer

EAB always kills within a single season once the first adult is detected feeding on the bark surface

Answer

Early symptoms include yellowing of lower leaves caused by root damage from EAB larval feeding near the root flare

Question 6

What is the purpose of foliar nutrient analysis (tissue testing) and how does it complement soil testing?

Accepted Answer

Foliar analysis measures actual nutrient concentrations in leaf tissue, revealing what the tree is actually absorbing — complementing soil tests which show nutrient availability but not uptake

Answer

Foliar analysis measures pesticide residue levels in leaves to determine re-entry intervals after spraying

Answer

Foliar analysis determines photosynthetic efficiency by measuring chlorophyll content of leaf tissue samples

Answer

Foliar analysis measures pathogen DNA in leaves to confirm disease diagnosis before prescribing treatment