GTBOP Moodle Review Prompts

Understanding Tree Pests: Disease Interactions, Invasive Threats, and Management Strategies

Dr. Ignazio Graziosi — January 15, 2026

Source: Corrected SRT transcript (Stage 1) + Archive Package (Stage 2) Prompts: 6 timestamp-linked review tasks

These short review tasks structure self-paced viewing by directing students to specific video segments and asking them to identify key points.

Review Task 1

Watch: 1:28 – 6:06 Task: Identify the three components of the disease triangle and the three levels of the spiral of tree decline. For each spiral level, list one example factor that Dr. Graziosi names. Key Points to Identify:

Disease triangle: pest, host tree, environment
Predisposing factors (e.g., soil compaction, urban environment, genetic potential)
Inciting factors (e.g., defoliating insects, drought)
Contributing factors (e.g., wood-boring insects, nematodes, Armillaria)

Review Task 2

Watch: 8:23 – 10:47 Task: Follow Dr. Graziosi's description of the emerald ash borer life cycle. List the diagnostic signs he describes for identifying an EAB-infested tree, and note the typical generation time. Key Points to Identify:

Larval galleries under bark disrupting phloem, cambium, and outer xylem
Water sprouts as a diagnostic feature
D-shaped exit holes from adult emergence
Primarily one generation per year, but a portion of the population takes two years

Review Task 3

Watch: 18:20 – 21:31 Task: Dr. Graziosi presents the invasion curve diagram. Describe how pest prevalence changes over time and explain why early detection matters for control options and cost. Key Points to Identify:

Introduction → low prevalence → exponential growth → carrying capacity (plateau)
Early: eradication may be possible; prevention effective
Late: only local control (individual tree protection); costs increase dramatically
Land managers become aware before the general public

Review Task 4

Watch: 23:57 – 28:00 Task: Describe the importation biological control program for EAB. Identify the three parasitoid wasp species' targets (what life stage each attacks) and explain why being specialists is an advantage. Key Points to Identify:

Two wasp species attack EAB larvae under bark (one uses vibrational cues and ovipositor to drill through bark)
One wasp species attacks EAB eggs
Specialists only attack EAB — won't waste their potential on other insects
Release technology: parasitized logs hung on trees; egg parasitoid released via small container ("O-binator")

Review Task 5

Watch: 29:42 – 38:30 Task: Compare crapemyrtle bark scale to the emerald ash borer in terms of: (a) host specificity, (b) available biological control, and (c) effectiveness of trunk injection. Note specific differences Dr. Graziosi highlights. Key Points to Identify:

CMBS is a generalist (feeds on apple, soybean, fig, beautyberry, St. John's wort in addition to crapemyrtle); EAB is more host-specific (ash + white fringetree)
No effective specialist parasitoid found for CMBS in the US; EAB has imported specialist parasitoids
Trunk injection not viable for CMBS (crapemyrtle absorbs poorly); trunk injection is a viable option for EAB in ash

Review Task 6

Watch: 42:25 – 49:19 Task: Explain Dr. Graziosi's two-part decision framework for determining whether to treat orange-striped oakworm. Then describe why clonal urban plantings are particularly vulnerable to this native pest. Key Points to Identify:

Part 1: Distinguish aesthetic vs. actual damage — threshold is ~25% defoliation
Part 2: Assess season — late-season defoliation less harmful (tree already stored nutrients)
Clonal nursery stock = low genetic variability = uniform susceptibility across all trees of the same clone
Urban heat island compounds the problem by accelerating insect development

Verification Checklist

[x] All review tasks reference specific, verifiable video segments
[x] Key points match content actually presented in those segments
[x] No external knowledge needed to complete tasks
[x] Tasks progress through the full presentation (early → middle → late)