Al-Khatib, Kassim. 2019. Herbicide Symptoms. University of California
Division of Agriculture and Natural Resources.
Costello, L.R. et al. 2003. Abiotic Disorders of Landscape Plants: A Diagnostic
Guide. Publication 3420. University of California Agriculture and Natural
Resources, Richmond, CA.
Ikley, Joe. 2020. North Dakota Herbicide Chart. North Dakota State University.


 

Glossary

Active Ingredient - chemical in an herbicide product responsible for herbicidal properties (i.e. toxicity to plants)
Adjuvant - material added to an herbicide product to enhance or modify performance, e.g. surfactant, sticker, spreader, drift retardant, defoaming agent, etc.
Calibration - process of measuring and adjusting the amount of pesticide a sprayer applies or delivers to a specific area; proper calibration ensures a sprayer is applying the correct amount of herbicide uniformly over a given area
Chlorosis - yellowing of leaves and stems due to the destruction of chlorophyll or failure of chlorophyll to form
Contact herbicide - herbicide that is not absorbed by a treated plant but instead affects only the portion of a plant that it touches
Cotyledons - seed leaves, the first leaves produced after a seed germinates; in monocots, a single cotyledon is produced, while two leaves are produced in dicots
Dicot - plant that has two seed leaves, often referred to as a “broadleaved” plant; dicots have leaf veins that form a net pattern and floral parts in multiples of four or five
Epinasty - abnormal bending or twisting of shoot tips or leaves
Fungicide - pesticide that controls fungi
Group - see herbicide group
Herbicide group - herbicide classification system that places herbicides into categories based on what mode of action the active ingredient affects. The classification is based on the Weed Science Society of America (www.wssa.net)
Incompatibility - condition that prevents herbicides from mixing together properly to form a uniform solution or suspension
Insecticide - pesticide that controls insects
Mode of action - how a herbicide acts on a plant and affects its growth; most modes of action inhibit a plant function or interrupt regulation of a plant’s physiology

Monocot - plant that has one seed leaf, for example grasses and sedges; monocots have parallel leaf veins and floral parts in multiples of three
Necrosis - browning or dying of plant tissue, often most evident in leaves
Pesticide - chemical used to kill or regulate or interrupt the growth and mating of pests; includes herbicides, fungicides, insecticides, rodenticides, and other chemicals
Phloem - plant vascular tissue (made up of living cells) that transports sugars from leaf to the stem and roots
Plant-Back Interval - period of time to wait after an herbicide application before seeding can occur without injury to seeded species
Residual - herbicide carryover that results in phytotoxicity
Soil Applied Herbicide - herbicide that is applied directly to soil rather than on growing plant
Sterilant - herbicide that persists in the soil for a long time (e.g. years) and kills all plants; “bare ground” herbicide
Systemic Herbicide - herbicide that is absorbed through leaves or roots then transported throughout the plant
Tank Mix - combination of two or more herbicides and/or other products (e.g. fertilizers, other pesticides) into a single spray tank, which are then applied simultaneously
Translocation - movement of sugars, water, mineral solutions, or other materials (e.g. herbicides) from one part of a plant to another
Xylem - plant vascular tissue (made up of non-living cells) that transports water and mineral nutrients from roots to stem and leaves

 

Photo Credits

Figure 1 - Department of Agriculture and Food, Government of Western Australia
Figure 2 - Paul Bachi, University of Kentucky Research and Education Center, Bugwood.org #5368856
Figure 3 and page 34 decorative photo - Tim Seipel, Montana State University
Figure 4 and page 10 decorative photo - Tim Seipel, Montana State University
Figure 5 - Montana State University Cropland Weed Ecology and Management Lab
Figure 6 - Montana State University Cropland Weed Ecology and Management Lab
Figure 7 - Paul Bachi, University of Kentucky Research and Education Center, Bugwood.org #5368555
Figure 8 and front cover (left) - Ansel Oommen, Bugwood.org #5573515
Figure 9 - Noelle Orloff, Montana State University
Figure 10 - Department of Agriculture and Food, Government of  Western Australia
Figure 11 - Noelle Orloff, Montana State University
Figure 12 - Cheryl Moore-Gough, Montana State University
Figure 13 - Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org UGA1392020
Figure 14 - Minnesota Department of Natural Resources, Bugwood.org UGA4214059
Figure 15 - Tim Seipel, Montana State University
Figure 16 - Brian Dintelmann; University of Missouri Weed Science Program
Figure 17 - Department of Agriculture and Food, Government of Western Australia
Figure 18 - William M. Brown Jr., Bugwood.org #5356825
Figure 19 - Tim Seipel, Montana State University
Figure 20, front cover (right), and page 14 decorative photo - Tim Seipel, Montana State University
Figure 21 - Tim Seipel, Montana State University

Figure 22 and front cover (center) - Rebekah D. Wallace, Univeristy of Georgia, Bugwood.org #5405600
Figure 23 and page 4 decorative photo - Jed Colquhoun, University of Wisconsin, Bugwood.org #5554008
Page 5 callout photo - Noelle Orloff, Montana State University
Page 6 callout photo - CG Ag Consulting, Cut Bank, MT
Page 7 callout photo - Dr. Mohammad Babadoost, University of Illinois
Figure 8 callout photo - William Jacobi, Colorado State University, bugwood.org #5366454
Page 11 callout photo - Noelle Orloff, Montana State University