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