Plant Sciences


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PLSC 323 Lecture Outline

Spring Semester 2020

Jan. 14 Introduction
Jan. 16 Terminology
Jan. 21 Terminology
Jan. 23 Weed control and herbicides
Jan. 28
Classification of herbicides
Jan. 30 1 Plant growth regulators
Feb. 4
Plant growth regulators
Feb. 6 Plant growth regulators
Feb. 11 Amino acid synthesis inhibitors
Feb. 13
2 Amino acid synthesis inhibitors
Feb. 18 Amino acid synthesis inhibitors
Feb. 20 Lipid synthesis inhibitors
Feb. 25 Lipid synthesis inhibitors
Feb. 27 3 Lipid synthesis inhibitors
Mar. 3
Seedling growth inhibitors
Mar. 5
Seedling growth inhibitors
Mar. 10
Photosynthesis inhibitors
Mar. 12
Test MID-TERM EXAM through seedling growth inhibitors
Mar. 24 Photosynthesis inhibitors
Mar. 26 Cell membrane disruptors
Mar. 31
Cell membrane disruptors
Apr. 2
4 Pigment inhibitors
Apr. 7
Factors affecting herbicide efficacy
Apr. 9
Management of herbicide resistant weeds
Apr. 14
Herbicide selectivity and interactions
Apr. 16 5 Regulatory aspects of weed control
Apr. 21 Weed and pest laws and regulations
Apr. 23 Pesticide development and registration
Apr. 28 Evaluation of pesticide toxicology
Apr. 30
6 Levels of success in weed suppression
May 5
Preventative and biological weed control
May 7
Cultural and physical weed control
May 12 Test FINAL EXAM
(Tuesday 8:00am - 10:00am)


Lectures: Loftsgard 114, 11:00 – 11:50 am, Tuesday and Thursday
Lab: Loftsgard 116, Friday (time dependent on section)

Instructor: Kirk Howatt, Loftsgard 470 F, 231-7209

Course Description: Introduction to biological, chemical, cultural, and physical weed control, characteristics of weeds and their identification, pesticide application and dissipation.
3 credits, 2 lectures, 1 discussion, 1 tutorial laboratory.

Course objectives:

  1. To develop a functional understanding of major herbicide modes of action, herbicide groups within each mode of action, and weed control characteristics of major herbicides within each group, including the visible symptoms of injury to plants caused by these herbicides.
  2. To understand factors that affect the efficacy of both soil- and foliar-applied herbicides.
  3. To understand regulatory aspects of weed control, including regulations and testing required before pesticides may be sold for public use.
  4. To understand the factors that affect dissipation of herbicides and other pesticides in the environment.
  5. To understand integrated weed management options, including biological, cultural, and physical weed control systems that can be used either alone or to complement herbicide-based programs.
  6. To develop skills to safely and accurately apply pesticides, including an understanding of equipment and calibration techniques.
  7. To improve identification of weed plants and seeds, including learning family and life cycle designations.

Lecture quizzes are scheduled for Thursday mornings.  Each quiz is worth 40 points and will be given during the last 10-15 minutes of the period.  There will be 6 lecture quizzes, a mid-term exam, and the final comprehensive exam.  The lowest 40-point quiz will be dropped.  This includes a missed quiz.

Make up quizzes will not be given. Instead, a missed quiz will be scored as a “0” and will be counted as the dropped quiz score.  Extraneous circumstances should be discussed with the instructor as soon as possible.  Don’t wait until the end of the semester to negotiate your way out of a missed score.  I deal with issues case by case as they occur.

Tentative Evaluation Procedure:

6 quizzes worth 40 points each, lowest one dropped (5 quizzes) = 200 points
Homework assignments =   50 points
Mid-Term Exam = 100 points
Final Exam = 100 points
Laboratory score = 350 points
Total = 800 points


Laboratory sections meeting in Loftsgard 116:

Section 1: 9:00-9:50am Fri.
Section 2:
10:00-10:50am Fri.
Section 3: 11:00-11:50am Fri.
Section 4: 1:00-1:50pm Fri.
Section 5: 2:00-2:50pm Fri.


Course grading:


Students with special requirements: Any students with disabilities or other special needs, who need special accommodations in this course are invited to share these concerns or requests with the instructor as soon as possible.  Assistance is also available from Disability Services in Wallman Wellness Center 170 (231-8463).

Veterans and military personnel: Veterans and students with special circumstances or who are activated are encouraged to notify the instructor as soon as the issue or conflict is known.

The Honor System: All students taking any course in the College of Agriculture, Food Systems, and Natural Resources are under the Honor System ( The Honor System is a system that is governed by the students and operates on the premise that most students are honest and work best when their honesty, and the honesty of others, is not in question. It functions to prevent cheating as well as penalize those who are dishonest. It is the responsibility of the students to report any violations of the honor pledge to the instructor, honor commission or the Dean of the College of Agriculture, Food Systems, and Natural Resources.

The academic community is operated on the basis of honesty, integrity, and fair play. NDSU Policy 335: Code of Academic Responsibility and Conduct applies to cases in which cheating, plagiarism, or other academic misconduct have occurred in an instructional context. Students found guilty of academic misconduct are subject to penalties, up to and possibly including suspension and/or expulsion. Student academic misconduct records are maintained by the Office of Registration and Records. Informational resources about academic honesty for students and instructional staff members can be found at

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