Review For Final Flashcards
Where in the country is over seeding commonly performed and why is it needed?
Over seeding is commonly performed in regions that use Bermuda grass (in the south and also southern parts of the transition zone) and want to have a “non dormant” or “green, growing turf” for play during the months that the C4 grasses are dormant.
Goals of managing the warm‐season species during summer months:
-Promote strong, lateral growth -Aerify, Verticut and Topdress -1/2lb N/1000 = adequate fertilization
How to use PGRs, fertility, and irrigation to slow the growth of warm‐season species:
-Reduce fertility 30 days prior to cultivation -Reduce irrigation by 30% 2 weeks prior to cultivation -Reduce irrigation completely 2-3 days prior to cult. -Use Primo to slow the growth of the native stand
Why are class‐D PGRs needed in the overseeding process?
- They are used as a pre-emergence for Poa annua (apply 6-8 weeks prior to overseeding)
How PGRs are used in the interseeding process?
–Slows bermudagrass growth which creates less competition for new C3 plants.
-it promotes lateral shoot growth and stolons when applied after new stand is mowed once
Effects of PGRs on disease when applied prior to disease and after disease is present
-prior to disease- can lower the amount of visible disease by creating thicker canopies and stronger plants which makes them more resistant to pathogens -after disease presence means slower growth=less “masking effect”
Relationship between DMI fungicides and Class B PGRs:
-they are chemically similar -Class B PRG’s have fungistatic properties -both interfere with fungi sterol biosynthesis -DMI fungicides also have PGR effects - they inhibit early GA pathways
How does Primo promote turfgrass tolerance to heat, drought, and cold stress?
- Less leaf area = Lower ET rates
- Lower ET rates = water conservation
- Promotes water retention within the leaves = Less plant to water and what plant is there, is more efficient with its water storage.
- increased cytokinins means more later growth and higher photosnthesis for plant survival
- stimulates carobohydrate production going into winter for C4 plants
What is the difference between phototropism and gravitropism? What is the chemical involved?
Phototropism - plant growth towards a light source Gravitropism - Plant growth towards the direction of gravity.
- Auxin is the chemical involved.
Auxin….What does it do?
-Inhibits the growth of tillers, promotes apical dominance. -Maintains active root growth
Cytokinin….What does it do?
-Promotes Lateral shoot growth and Inhibits root growth. -Opposite of Auxin
What is the main function of Gibberellins in a plant?
Cell elongation. Makes the plants tall/long. Induces seed germination and makes plants flower faster.
What does ABA do?
- Prevents cell division and enlargement
- induces stomatal closure - drought stress mechanism
What happens to a plant when it is exposed to high concentrations of ethylene?
• Stunted growth • Thick stems • Leaf yellowing • Leaf abscission
Define Epinasty:
Downward curvature of branches or leaf petioles
Absisic Acid is directly related to :
Water Loss in plants
What is 2-4D
A selective herbicide used to kill broadleaf weeds
What processes do plant hormones affect?
Most cellular activities including: -cellular division, elongation and differentiation. -Patter formations -Organ formation -Reproductive cycles -Seed germination -Stress responses
Auxin was first described by who?
Charles Darwin
In relation to a light source, where does Auxin accumulate?
Opposite the light source
What Cehmical Promotes Lateral shoot growth and Inhibits root growth?
Cytokinin
What Chemical -Inhibits the growth of tillers, promotes apical dominance. -Maintains active root growth
Auxin
What does ABA stand for?
Abscisic acid
Major problems with old PGR chemistries and the settings they were mainly used in
Older chemistries were set up to affect all forms of GA. The only one needed was GA1 but they were all affected. Older chemistries typically used to control growth in out-of-play areas • Areas with low monetary value • High chance for phytotoxicity burn to occur
Differences between Type I and Type II turf PGRs for old classification
Type 1 - slowed overall rates of cell division
Type 2- slowed overall rates of cell elongation
Criteria which determines how a new chemical is classified:
Classified by
- Mode of Action (what do they do?)
- Site of Uptake (leafs, roots etc.)
- Effects on Turfgrass development
Class A:
Late GA synthesis blockers
Class B:
Early GA synthesis blockers (Blocks all forms of GA)
Class C:
Mitotic inhibitors (cell division)
Class D:
Herbicidal with PGR activity
Class E:
Ethylene production enhancement
Class F:
PGR combinations
Site of uptake for Primo and field settings it can be used in
Site of Uptake: Crown
• Use on all turf species
• Can be used on greens,
fairways, tees, roughs
• Apply to actively-growing turf
• Repeat every 3-4 weeks
- Best PGR to maintain Poa annua
Describe Morphological changes to the plant in response to GA blockers/inhibitors
Class A (Late GA synthesis blocker)
• Rates of cell elongation slow
• Shorter internodes and compact leaves
• Increased density; same number of leaves but
smaller stem length
• Vertical growth slows
• Resources (carbohydrates) redirected to tillers,
rhizomes, and stolons
• Lateral spread increases turf density
Difference between Embark 2S and Embark TO and main use for the product
Embark TO is 10% as potent as Embark 2S.
While both of them are not to be used on young plants, Embark TO can be used CAREFULLY on putting greens.
Which plant hormone does Proxy stimulate and the main use for the product.
Stimulates Ethylene release.
Main use for the product is to prevent the growth of seedheads in Poa Annua.
What is the main goal when applying Embark TO?
TO suppress seedheads on Poa Annua and to suppress foliar growth on C3 grasses in general.
- It is a mitotic inhibitor
- Inhibits cell division and cell differentiation in meristems
Paclobutrazol
• Site of uptake: roots
• Need to water-in
• Use on cool-season species
• Can be used on bentgrass
greens and fairways
• Mainly for Poa annua reduction
• Apply to actively-growing turf
• Slow uptake (1-2 weeks)
• Effects last 4-6 weeks
Blocks ALL forms of GA..
Embark TO
- 10% a.i. as 2-S
- Site of uptake: leaves (foliar)
- Use on cool-season species
- Safe to use on greens
- DO NOT apply to young tissue
- Poa annua seedhead suppress
- Suppress foliar growth of turf
- Rapid effects (5-7days)
- Effects last 3-4 weeks
Embark 2S
• Mefluidide (Embark 2-S)
• Labeled in mid-1970s
• Site of uptake: leaves (foliar)
• Use on cool-season species
• DO NOT use on greens
• DO NOT apply to young tissue
• Used for suppression of Poa
annua seedheads
• Rapid effects (5-7days)
• Effects last 3-4 weeks
How do Class D products work?
• Inhibit growth by disrupting amino acid
synthesis or fatty acid biosynthesis
• Amino acids - proteins
• Fatty acids - cell membranes
Where do you primarily use Class D products?
Why?
- Out of play areas
- Rough
- Steep Hillsides
- Road Sides
Use is in these areas becuase the label rates usualy cause phototoxicity.
Why would you apply a Class E product?
To slow turf growth and seedhead production.
Mainly used for Poa Annua
Class B Considerations:
- Mainly for Poa Annua reduction
- Site of Uptake: Roots = slow uptake 1-2 weeks
- Effects last 4 - 6 weeks
- Need to water in (root uptake)
- Apply to actively growing turf
Class A considerations:
- Vertical growth slows
- Carbohydrates (resources) redirected to Tillers, Rhizomes or Stolons
- Lateral Spread increases turf density
- Site of uptake : Crown
- Can be used anywhere
- Apply to actively growing turf
Class C Considerations:
- Inhibits cell division and differentiation in meristems (It stops the plant from growing. period)
- Site of uptake : Leaves
- rapid effects : 5-7 days, Lasts 3 - 4 weeks.
- Used to suppress Poa Annua seedheads
- Some more potent forms (Embark2S) can have very bad phototoxicity problems
- Apply to actively growing turf
Class D Considerations:
- Site of uptake: Leaves or Roots
- Primarily used for low-maintenence areas
- ****Phototoxicity is likely to occur at label rate****
- Use Sub-Lethal rates for PGR results
Class E Considerations:
- Uptake : Leaves (foliar)
- Visual results within 2 weeks
- **Typically mixed with Primo Maxx**
- Suppresses seed heads (poa annua)
- Add fertilizer to minimize potential decrease in rooting
*
Class F Considerations:
- Combinations of PGR’s (PGR Cocktail)
- Uptake : depends on products used
- Growth Suppression and Poa Seedhead Control
- Rebound effect not as bad
What type of cultural factors (mowing, fertility…etc.) should be considered when choosing a PGR?
- Using PGR’s slows plant growth which means less mowing and less clippings.
- Mowers last longer…less maintenance, less hours
- Lesser chance for scalping
- Trimming and Edging
- Should supplement with Iron or Nitrogen to avoid chlorosis (leaf yellowing)
What is the jar test and why is it necessary to perform when working with a new PGR?
- Mixing the chemicals (at the same ratios as you would in the tank) in a jar to see if they are compatible.
- They could form a percipitate and clog nozzles
- They might not mix and instead form layers
Should a new PGR be tank mixed and sprayed on a high‐value area? If not, how should you approach a new PGR for use on your course?
- No it shouldn’t. It should always be tested on a nursery or practice green or out of play area.
- Do Not tank mix a new product. See what it’s effects are alone first.
- Ask other Superintendants what rates they use and compare to label rate to find a good starting point.
- Apply to healthy, actively growing turf
Why should nozzle size and travel speed be considered when working with PGRs?
- Nozzle size determines the droplet size
- Small droplets for Foliar uptake
- Large droplets for Root uptake
- Travel speed determines how much product you are putting down over a certain area.
What are important factors to considder when planning a PGR application?
- Site of uptake for the product
- Nozzle Size
- Carrier Volume
- Using a surfactant or not
- SPeed of tavel for sprayer
What type/class of PGR can help minimize or avoid scalping when irrigation or rainfall is excessive?
- GA inhibitors
- Class A or Class B
What type/class of PGRs should be used on the hard‐to‐mow or low maintenance areas?
- A PGR that slows vertical growth….Less mowing of dangerous area = less chance for accidents
- Class C would beneficial…Class A or B would be okay too
What are some reasons that you may need to increase or decrease your rate of application?
- Time of year
- Environmental conditions
- species
- previous records showed that the last application did too much or not enough.
PGRs can make the striping effects better in your turf…..how?
PGR’s increase turf density and usually change leaf morphology.
Describe the differences in growth habit between annual bluegrass and creeping bentgrass
Bentgrass - has stolons, doesnt produce seedheads when its mowed, Poa Annua - Bunch type, (some have weak stolons), Abundant seedheads even if mowed short,
describe Differences in stress and disease tolerance between the two grass species:
Poa Annua - less tolerant to drought stress than Bentgrass, prone to anthracnose and summer patch, light green color Bentgrass - Not prone to anthracnose or summer patch, Dark green in color
Major problems associated with annual bluegrass invasion long and short‐term:
It detracts from uniformity of bentgrass canopies, Changes ball roll, changes speed, affects the way you manage your turf,
what Growth stage is chemical control of annual bluegrass is most effective?
Mid-Late Boot Stage when their is a bulge in the leaf sheath is the best time to apply chemical control.
Purpose of Growing Degree Day (GDD) models and how they benefit the turf manager
Purpose of GDD model is to track heat units which accumulate throughout the year and are necessary for the growth and development of plants and insects. They benefit us because it provides a science based window of opportunity to make your treatments as effective as possible.
Why are Primo and Proxy typically tank mixed together (what does each chemical do)
Proxy stimulates Ethylene production which controls seed head production but causes chlorosis (yellowing) Primo inhibits GA production and prevents the leaf blades from elongating while counteracting proxy’s chlorosis to maintain the dark green color.
What type of “effect” are you getting with using both products?
a Synergistic effect
What is Embark used for?
Poa Annua seed head suppression
What Embark product is labeled saying it can be used on greens?
Embark TO
What is one advantage of using Embark TO?
No reapplication is required
If timed correctly, what product is the best for suppressing Poa Annnua seed head production? How much can it control?
Embark TO…can control 70-80% if timed correctly
Why is annual bluegrass so difficult to control by chemical and/or mechanical methods?
It can have several ecotypes in one stand each ecotype has slight genetic differences that allow it to be extremely resiliant and resistant to some products. Poa Annua is highly adaptable to different conditions It makes A LOT of seeds that are viable for multiple years
Major pros and cons associated with chemical controls for annual bluegrass
Chlorosis Some products cannot be used on KBG or greens hight Bentgrass Problems with incosistency Most products require multiple applications
When should you apply pre-emergence products for controling crabgrass?
prior to the soil warming up
What time of year should you apply chemical treatments to control broadleaf weeds most effectively?
In the Fall
What happens if you apply herbicides during flowering?
They are ineffective and wasteful
when using older PGR’s like Cutless and Trimmit…what do you need to do in order for them to be effective?
water them in, they are root uptake products
What do you need to be prepared for when using some of the new products?
prepare to manage the stand because the product may work “too well”…
