We think you have liked this presentation. If you wish to download it, please recommend it to your friends in any social system. Share buttons are a little bit lower. Thank you!
Presentation is loading. Please wait.
Published byKenzie Keighley
Modified about 1 year ago
v121903© 2003, Purdue Univ.1 Corn Growth & Development Related to Herbicide Use Bob Nielsen Purdue University Web:
© 2003, Purdue Univ.2v Post-Emergence Herbicides The application of many of these is restricted beyond certain corn plant heights or leaf stages. Where both height & leaf stage are listed on a label, the more restrictive of the two should be used for decision-making. The reasons for these label restrictions are both physical and physiological.
© 2003, Purdue Univ.3v Crop & Weed Canopies Large corn canopies may intercept more of a broadcast herbicide application than will that of the intended “victims” (i.e., the weeds). Larger corn plants often also means larger weeds that are more difficult to kill. Physical Reasons for Label Restrictions:
© 2003, Purdue Univ.4v Ever Larger Leaf Area With every subsequent stage of corn development, Leaf area per corn plant increases. With broadcast applications, herbicide interception per corn plant increases. Risk of herbicide injury increases. Physiological Reasons for Label Restrictions:
© 2003, Purdue Univ.5v Sexual Development Beginning at about leaf stage V5, the uppermost (and eventually harvestable) ear is initiated, as is the tassel. These reproductive structures are often quite sensitive to herbicides absorbed by the plant. Physiological Reasons for Label Restrictions: Leaf stage V5 = Lowermost five leaves with visible leaf collars
© 2003, Purdue Univ.6v Ear Shoots on V6 Plant Ear shoot at stalk node #4 Ear shoot at stalk node #6 Ear shoot at stalk node #5
© 2003, Purdue Univ.7v Ear Shoots on a V9 Plant
© 2003, Purdue Univ.8v Leaf Cuticle Changes Over Time From VE (emergence) to V4: “Leaves of corn…had crystalline deposits of wax on the surface of the cuticle.” “These crystals reduced [herbicide] spray retention and leaf wettability by trapping air under the spray droplets.” Rapid changes from V5 to V8: “… smooth wax film on the leaves ” “ Spray retention increased from about 30% at the V4 stage to about 80% at the V6 stage.” Source: Physiological Reasons for Label Restrictions:
© 2003, Purdue Univ.9v The Achilles' Heel of Labels Many labels do not clearly explain… How plant height should be measured or What is meant by a particular leaf stage.
© 2003, Purdue Univ.10v Corn Plant Height Most agronomists agree that corn plant height should be that of free- standing plants. Measure height from the soil surface to the arch of the uppermost leaf that is at least 50% emerged from the whorl. Herbicide Labels? Usually not clear whether plant height refers to free-standing plants Herbicide Labels? Usually not clear whether plant height refers to free-standing plants
© 2003, Purdue Univ.11v Corn Leaf Staging Corn leaf staging is technically quite simple. All it requires is the ability to identify the right parts of a leaf and to be able to count.
© 2003, Purdue Univ.12v Identifying Leaf Parts A corn leaf consists of three distinct morphological components: The leaf blade The leaf collar The leaf sheath
© 2003, Purdue Univ.13v Leaf Staging Methods Leaf collar method Count only leaves with visible leaf collar Begin with lowermost leaf that is shorter than the others and has a rounded tip. End with uppermost leaf with visible leaf collar. Rounded leaf #1 w/ collar Leaf #5 w/o collar Leaf #4 w/o collar Leaf #6 just visible Leaf #2 w/ collar Leaf #3 w/ collar Source of Digital Image:
© 2003, Purdue Univ.14v Leaf Staging Methods Droopy leaf method Begin with lowermost leaf that is shorter than the others and has a rounded tip. End with uppermost leaf that is at least 50% emerged from whorl. Leaf tip often points down, but not always Source of Digital Image: Rounded leaf #1 w/ collar Leaf #5 w/o collar & not droopy Leaf #4 w/o collar but droopy Leaf #6 just visible Leaf #2 w/ collar Leaf #3 w/ collar Method Used by Hail Adjusters
© 2003, Purdue Univ.15v Compare The Two Methods Leaf collar method: Stage late V3 Droopy leaf method: Stage between late V4 & early V5 Source of Digital Image:
© 2003, Purdue Univ.16v Herbicide Label Uncertainty Older labels ignored the first, rounded tip, leaf and ended with the uppermost leaf that was at least 50% exposed from whorl. A bastardized “droopy leaf” method that results in roughly the same numerical leaf stage as the leaf collar method. Source of Digital Image: #1 #2 #3 Ignore Almost #4
© 2003, Purdue Univ.17v Herbicide Label Uncertainty Older labels ignored the first, rounded tip, leaf and ended with the uppermost leaf that was 50% exposed from whorl. A bastardized “droopy leaf” method that results in the same numerical leaf stage as the leaf collar method. Newer labels purport to define leaf stages according to the leaf collar method. Is some question about whether the first, rounded tip, leaf is counted, however. Bottom Line: Check with your chemical technical representative to verify which definition is appropriate for the herbicide you intend to use. Bottom Line: Check with your chemical technical representative to verify which definition is appropriate for the herbicide you intend to use.
© 2003, Purdue Univ.18v Pop Quiz! Using the leaf collar method, what is the leaf stage of this plant? #1 #2 #3 #4 #5 #6 ANSWER: Late stage V6 to early V7 Source of Digital Image:
© 2003, Purdue Univ.19v When Lower Leaves Go Kaput Determining growth stages on older plants is often more difficult because lower leaves naturally wither away as the plant develops. But the missing leaves must still be accounted for when staging the plant.
© 2003, Purdue Univ.20v Stalk Elongation to the Rescue Stalk elongation is increasingly evident after growth stage V4. From VE to V4, stalk elongation is very insignificant. During this time, all the above- ground plant tissue consists of leaves and rolled-up leaves.
© 2003, Purdue Univ.21v Recognizing Stalk Nodes After growth stage V4, the pace of stalk elongation picks up. Individual stalk nodes can easily be detected after splitting a stalk down the middle.
© 2003, Purdue Univ.22v Identifying Individual Nodes Stalk nodes serve as the point of origin for roots, leaves, tillers, and ears. Careful stalk splitting will verify that Node #5 is usually the first individually recognizable stalk node. Key Trivia for Staging Corn: Stalk node #5 is the point of attachment for Leaf #5. Key Trivia for Staging Corn: Stalk node #5 is the point of attachment for Leaf #5.
© 2003, Purdue Univ.23v Help in Identifying #5 Node The internode length between Node #4 and Node #5 is usually less than ½ inch, whereas that between Node #5 and Node #6 is 1 inch or longer. ½ inch or less Node #5 1 inch or greater Node #6 Node #5 Nodes #1 - #4
© 2003, Purdue Univ.24v Once #5 Node is Identified… Identify which leaf sheath connects to that node, then count upward to uppermost leaf with visible leaf collar to determine leaf stage of plant. Leaf sheath attachment to stalk node
© 2003, Purdue Univ.25v Stress, Corn, & Herbicides Effects of severe stress can include… Shorter than expected plants for growth stage due to stunted stalk elongation. Altered plant metabolism that increases sensitivity to herbicides or decreases the plants’ ability to detoxify herbicides. Excellent growing conditions may increase risk of injury by increasing rate of herbicide uptake. Final Thoughts:
© 2003, Purdue Univ.26v Symptomology & Diagnostics Sometimes, the morphological symptomology of herbicide injury points to the time of application. By which plant parts are affected By recovery, or lack thereof, subsequent to damage Final Thoughts:
© 2003, Purdue Univ.27v Plants can confirm… Plant injury by Hornet™ + 2,4-D herbicides Lower 9 to 10 leaves appeared normal in color and size Remainder of leaves, stalk, and tassel severely stunted and malformed Plant appearance + GDD data supported V9 or V10 as timing of application. Beyond V5 or V6 label limits
© 2003, Purdue Univ.28v Hungry for More? Check out one of these fine Web sites…
Corn growth & development. Growth Stages of Corn.
Grain Crops Extension, University of Kentucky Corn Growth Stages Chad Lee, Ph.D. Grain Crops Extension Specialist University of Kentucky.
CORN Growth and Development Chad Lee Grain Crops Extension Specialist ● © Chad Lee, Univ. of Kentucky,
Crop Structure and Development Montana Small Grain Guide.
Corn Growth and Development Chad Lee Grain Crops Extension Specialist ●
Field bindweed Scientific name: Convolvulus arvensis Family: Convolvulaceae (Morning Glory family) Life cycle: Perennial Where found: Range, Cropland.
Updated April 2012 Collecting Plant Tissue Samples NCDA&CS Agronomic Division Plant/Waste/Solution/Media Section.
Corn Growth and Development. Outline Stress and yield loss Growth staging Vegetative stages Reproductive stages Conclusions.
Plant Life Cycle 4.01 Explain the growth process of plants.
Morphological Characteristics of High Yielding Rice Varieties.
Virtual Academy for the Semi Arid Tropics Course on Insect Pests of Groundnut Module 1: About Sorghum At the end of this lesson, you have learned to answer.
Plant Growth and Development. Types of Growth Apical meristem: plant tissue made of actively dividing cells. Primary growth and located at the tip of.
Level II Agricultural Business Operations. Scale proposed by the Dutch phytopathologist, Jan C. Zadoks Know as Zadoks scale, it gives the plant a.
Study Skills Presenting your work Moodle. Stages to complete an assignment 1. Understand the assignment brief 2. Find the information needed 3. Evaluate.
After completing 3 Units in this Lesson, you have learned to answer: 1.Why weed control is important in pearl millet crop? 2.When is the critical period.
At the end of this Lesson, you have learned to answer: 1.How pearl millet is a better crop than other cereal crops like maize, wheat, etc.? 2.How many.
Weed life cycles. Vegetative reproduction Production of new plants from vegetative structures Clones=daughter plants=ramets Genetically identical.
After successful completion of this Lesson, you have learned to answer: 1.How pearl millet is a better crop than other cereal crops like maize, wheat,
Virtual Academy for the Semi Arid Tropics Course on Insect Pests of Groundnut Module 7: Cropping Systems After completing this lesson, you have learned.
Plant Growth Objectives 1.Identify the parts of the plant that are responsible for growth 2.Explain the mechanisms of plant growth 3.Discuss the external.
Selecting Herbicide Original by Brent Niemeyer Modified by Georgia Agricultural Education Curriculum Office July, 2002.
Plant tissue analysis for testing nutrients deficiency in Banana.
Unit C 4-10 Basic Principles of Agricultural/Horticultural Science.
Thursday, February 23rd Plant Growth and Structure.
Role of Seed Treatments in Plant Competition Clarence Swanton University of Guelph.
Plant Tissues Chapter 28 Part 1. Impacts, Issues Drought Versus Civilization Without plants, we would die – prolonged drought can destroy crops and.
14.4 Plant Growth How Plants Grow. Objectives By the end of the lesson, students will be able to explain how plant growth and animal growth differ.
Module VI: Nutrient Deficiency Symptoms Lesson 4: Deficiency Symptoms of Micronutrients Unit 2: Zinc Deficiency Symptoms After completing this Unit you.
Modern Biology: Section Plant Stems. In contrast to roots, which are mainly adapted for absorption of and anchoring, stems are usually adapted to.
Unit C 5-2 Basic Principles of Agricultural/Horticultural Science.
Understanding Light, Temperature, Air, and Water Effects on Plant Growth.
Plant Parts Chapter #3. What are the parts of a plant? Node: swollen part of stem where buds form (leaves or stems grow here) Cotyledons: leaves formed.
Beginning Pruning Wisconsin Grape Growers Association Tuesday January 5, 2010 Timothy K. Rehbein University of Wisconsin Extension Agricultural Agent –
By C. Kohn, WUHS Based on “Botany Basics”, a module by Oregon State Univ.
Plant Structure. Hierarchy of a Plant Body Extreme developmental plasticity in plants Structurally change morphology, external form, to better suit environment.
Module X: Soil Moisture Relationships and Irrigation Lesson 2: Irrigation in Chili Pepper Cultivation After completing this lesson, you have learned to.
Introduction: Rice crop needs seventeen essential nutrients. Out of these Nitrogen, Phosphorus, Potassium, Iron, Manganese, Zinc and Copper are considered.
Vegetative Propagation Development of plants from Stem Cuttings.
Task How would you define the term “growth”? Write a sentence containing the word growth.
STC Plant Growth and Development Lesson 6: Observing: Leaves and Flower Buds Kennewick School District.
Plant tissue analysis for testing nutrients deficiency in grape.
Growth and Development. Growth It is a process involving cell division and cell enlargement. Cell divisions (Mitosis or Meiosis) is process which leads.
Very simple to create with each dot representing a data value. Best for non continuous data but can be made for and quantitative data 2004 US Womens Soccer.
Identifying, Classifying, and Selecting Turfgrass Student Learning Objectives. Instruction in this lesson should result in students achieving the following.
Plant tissue analysis for testing nutrients deficiency in Banana Next End.
Number of days suitable for fieldwork Defined as "one where weather and field conditions allow work with machinery to be completed in fields a major portion.
Unit 1: Corn Diseases. Corn Smut Caused by fungus: Ustilago maydis Most widely recognized corn disease Symptoms: Complete barrenness in most plants.
Plant Responses Response to light Response to water Response to gravity Contents What do plants respond to? Using plant hormones Summary quiz.
© 2017 SlidePlayer.com Inc. All rights reserved.