78 lines
4.0 KiB
Markdown
78 lines
4.0 KiB
Markdown
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# GTBOP Moodle Review Activities
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## Weed Control in the Landscape & Nursery — Dr. Mark Czarnota (November 18, 2021)
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**Source:** Corrected SRT (Stage 1) — GTBOP_Transcript_2021-11-18_WeedControl.srt (786 blocks)
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**Structural Reference:** Stage 2 Archive Package — GTBOP_Archive_Summary_2021-11-18_WeedControl.md
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**Review Tasks:** 6
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---
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### Review Task 1
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**Watch:** 4:23 – 6:40
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**Task:** List the six characteristics Dr. Czarnota identifies as predictors of weediness, then describe the specific real-world example he uses for the first characteristic.
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**Key Points to Identify:**
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- The six characteristics (vegetative reproduction, abundant seed production, rapid establishment, seed dormancy, adaptive traits, disturbed site colonization)
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- Yellow and purple nutsedge as the example of vegetative reproductive structures
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- Pigweed seed production numbers (5,000–10,000 seeds per plant)
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---
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### Review Task 2
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**Watch:** 15:44 – 18:06
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**Task:** Identify the four biological control methods Dr. Czarnota describes and note the specific target weed or pest for each. For one method, describe why it was discontinued.
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**Key Points to Identify:**
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- Grass carp for submerged aquatic weeds (8–10 per surface acre)
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- Goats for kudzu (followed by herbicide on regrowth)
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- Thistle weevil for musk thistle (larvae prevent seed development over 2–3 years)
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- DeVine bioherbicide for strangler vine in citrus (worked too well — eliminated the vine and left no host for the biocontrol agent)
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---
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### Review Task 3
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**Watch:** 21:07 – 23:43
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**Task:** Explain the key difference between how pre-emergent and post-emergent herbicides work, and identify the critical weather requirement for each type after application.
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**Key Points to Identify:**
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- Pre-emergent: applied before germination, needs 0.5–1 inch of rain to move into top quarter inch of soil
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- Post-emergent: applied after emergence, needs a dry period for leaf absorption
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- Glyphosate as the only broad-spectrum systemic (phloem-loaded) post-emergent herbicide
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---
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### Review Task 4
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**Watch:** 26:20 – 29:08
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**Task:** Describe the modes of action for glyphosate and the dinitroaniline herbicides. For glyphosate, identify the three amino acids affected and explain why this matters for mammalian safety.
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**Key Points to Identify:**
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- Glyphosate inhibits EPSP synthase, blocking production of tryptophan, phenylalanine, and tyrosine
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- The EPSP synthase pathway does not exist in animals — humans obtain these amino acids through diet
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- Dinitroanilines disrupt microtubule formation during cell division, preventing chromosome separation
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- Visual symptom of dinitroaniline overdose: club rooting
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---
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### Review Task 5
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**Watch:** 29:42 – 35:16
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**Task:** From the pre-emergent and post-emergent products Dr. Czarnota reviews, identify the two products he recommends most highly for landscape use and note their key advantages and any limitations.
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**Key Points to Identify:**
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- Dimension (dithiopyr): most underutilized; safe on turfgrasses, broad woody ornamentals, some perennials and annuals
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- Marengo (indaziflam): up to 16 weeks control; established woody ornamentals only; does not control nutsedge
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- Combination granular products (Snapshot, FreeHand) provide both pre-emergent control and oxyfluorfen burndown
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---
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### Review Task 6
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**Watch:** 36:40 – 39:30
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**Task:** List the common application errors Dr. Czarnota identifies that reduce herbicide effectiveness, and note his recommended application frequency for field versus container production.
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**Key Points to Identify:**
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- No rain after pre-emergent application (needs rain within 72 hours)
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- Rain immediately after post-emergent application
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- Poorly calibrated equipment
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- Wrong herbicide for the target weed
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- Applying pre-emergent after weeds have already germinated
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- Field: 2–4 applications/year; Containers: 4–6 applications/year
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---
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*Generated for UGA Center for Urban Agriculture / GTBOP Moodle Course Activities*
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*Source: Corrected SRT (Stage 1) — GTBOP_Transcript_2021-11-18_WeedControl.srt (786 blocks)*
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*Structural Reference: Stage 2 Archive Package*
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