5/14/2020 Plant Morphology and a Seedling Identification Key to ID Weeds Chris Proctor 2020 Crop Scout Training Carry your Weed ID Guide Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 1 5/14/2020 Life Cycle Annuals Complete life cycle within 12 months Reproduce by seed Winter Annuals Summer Annuals Life Cycle Biennials Require two years to complete life cycle Vegetative first year Rosette Reproductive second year Bolt Common mullein Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 2 5/14/2020 Life Cycle Perennials Requires more than two years to complete life cycle Herbaceous Vegetative first year Reproductive second year Extensive root system Vegetative Reproduction (rhizomes, stolons) Quackgrass Johnsongrass Broadleaf Plants Cotyledons Branched Stems 1st True Leaf(s) 2nd True Leaf(s) Example: Soybeans Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 3 5/14/2020 Broadleaf Plant Parts (pg. 66) Common Leaf and Cotyledon Shapes Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 4 5/14/2020 Common Leaf and Cotyledon Shapes Common Leaf and Cotyledon Shapes Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 5 5/14/2020 True Leaves Emerge after cotyledons Simple Pinnately Palmately Compound Compound Leaf Structure? Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 6 5/14/2020 Leaf Margins Leaf Margin type? Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 7 5/14/2020 Leaf Position Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 8 5/14/2020 Opposite Opposite, then alternate Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 9 5/14/2020 Alternate Ocrea Occurs in the Polygonaceae (Buckwheat) family Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 10 5/14/2020 Identifying Grass Weeds Grass and grass-like plants Grasses Monocot Hollow stems and nodes Leaves are 2-ranked Parallel veins Example: Corn Grass-like plants Solid Stems without nodes Leaves are 2-or 3-ranked and have parallel veins Example: Yellow nutsedge Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 11 5/14/2020 Plant Parts Stem or Sheath Shape Grass stems are round to somewhat flattened or distinctly flattened If in doubt, the stem is probably not distinctly flattened. Nutsedge is not a grass and has a triangular stem Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 12 5/14/2020 Distinctly Flattened Stem Sandbur viewed at right angles Collar Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 13 5/14/2020 Ligule A projection at the base of the leaf blade Membranous: a solid, shiny projection Hair-like: a fringe of hairs Absent: most seedlings do not have a ligule on the first 1-2 leaves Example: Barnyardgrass Pull leaf back from stem May require a hand lens to see Ligule Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 14 5/14/2020 Membranous Ligule Membranous ligules may and appear hairlike Hair-like Ligule Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 15 5/14/2020 Membranous or Hair-like? Leaf and Sheath Pubescence (Hair) Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 16 5/14/2020 Blade Width and Length Short wide vs. long narrow Sheath Margins Split United Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 17 5/14/2020 Leaf Auricles from the base of the leaf May dry up and disappear as plant ages Leaf Midrib or Midvein Most leaf midveins are faint or obscure A few grasses have prominent midvein Wider, lighter color and may be prominent below Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 18 5/14/2020 Growth Habit Seedling Growth Habit Developing Plant Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 19 5/14/2020 Leaf Twist While most seedling grass leaves may twist in random directions, a few have prominent twist (on first leaves) Seed Size and Shape Grass seed can be an important clue to the identity of small grass seedlings. The seed of grasses often remains attached to the primary root after germination Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 20 5/14/2020 Identifying Grass Weeds 1. Stem shape? 2. Ligule type? 3. Hair on blade and sheath? 4. Blade width or length? 5. Sheath margins? 6. Auricles? 7. Growth habit? Use the IPM Field Scout Guide Key to identify this weed 1. Identify the cotyledon shape. Page 66-67 2. Are the first true leaves alternate or opposite? Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 21 5/14/2020 Keying out a broadleaf seedling 3. Is an ocrea present? 4. Large cotyledons with prominent, recessed midvein? Keying out a broadleaf seedling 5. Nick in tip of first true leaves? Stem reddish-violet? Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 22 5/14/2020 Keying out a broadleaf seedling 6. Smooth or hairy? 7. Rough or glossy? 8. Leaf Shape? Distinguishing similar species Palmer Amaranth Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 23 5/14/2020 Weeds not in the key? Look in the boxes at the bottom Grass Seedling I.D. Key Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 24 5/14/2020 Follow Us On Twitter: THANK YOU! @UNLWeedSci QUESTIONS? CropWatch.unl.edu @UNL_CropWatch Email: [email protected] Chris Proctor Please note that materials in this document/presentation may be copyrighted. Contact the author for information. 25.