Is that artificial turf or real grass? Its thicker than Bermuda! 1
Using Plant Growth Regulators Growth regulators DO NOT interfere with plant respiration, photosynthesis, or other internal plant functions What are the risks? What are the rewards? Cool Season Warm Season Five Groups of Plant Hormones Plant produced natural compounds that inhibit or promote plant growth AUXINS *STIMULATE CELL GROWTH & EXPANSION *MOVES AWAY FROM LIGHT TO BALANCE GROWTH GIBBERELLINS *MAKE STEMS LONGER BY PROMOTING GROWTH BETWEEN NODES CYTOKININS *FOSTER PLANT CELL DIVISION, MAKING NEW ROOTS AND SHOOTS ABSCISIC ACID *ALERTS PLANT THAT IT IS WATER STRESSED *MADE IN DROUGHTED ROOTS & LEAVES ETHYLENE *GAS THAT AFFECTS SEED & FRUIT RIPENING *TRAVELS THROUGH AIR TO OTHER PLANTS Work together coordinating growth & development of cells Plant Growth Regulators History Japan 1930 s Research in rice production to combat Foolish Seeding Disease Used on seedless grapes throughout California by 1962 Designed to stimulate a specific plant function or mimic a plant hormone that will help, hinder, or change the pattern of plant growth Function as chemical messengers for intercellular communication, influencing the growth and differentiation of plant cells, tissues, and organs Turf grass growth regulators original goal was to slow grass growth to reduce frequency of mowing and amount of clippings. Reducing labor costs was a powerful motivator for the development and use of PGRs on turf Grass appearance was improved by preventing seed head and stalk formations Gibberellins (GAs) Gibberellic Acids *Plant hormones that regulate growth and influence various developmental processes, including stem elongation, germination, dormancy, flowering, seed head development, and enzyme induction *Produced in greater mass in colder temperatures *Promote cell division in the stem *Activates protein, binds to DNA producing an enzyme to stimulate growth in the embryo *As of 2003, there were 126 different GAs 2
Gibberellin Biosynthesis Inhibitors TYPE I CELL DIVISION INHIBITORS *Used on low and medium maintenance turf grass *Foliage absorbed, inhibit vegetative growth and seed head development *Phytotoxicity issues TYPE II CLASS A & CLASS B GIBBERELLIN INHIBITORS *Used on high maintenance turf grass *Foliar and systemically absorbed *Plant cells do not elongate, internodes become shortened, and overall plant growth is reduced Type II Class A Gibberellin Inhibitors TRINEXAPAC ETHYL *Synthetic PGR used to control growth of various grass & crop species *Foliar absorbed and translocated to the growing shoot *Approximately seven (7) days to act *Inhibits the action of the key enzyme in the formation of GA1 late in the pathway, therefore it is less physiologically disruptive and injurious to turf grass *In the absence of gibberellins in the internodes, the plant s shoot growth is slowed, redirecting energy to the reproductive parts (root development) Type II Class B Gibberellin Inhibitors PACLOBUTRAZOL *Inhibits gibberellin biosynthesis early in the pathway (phytotoxicity issues possible) *Systemic = Root absorbed and transported via xylem *Approximately 10 14 days to act *Inhibits gibberellin biosynthesis, reducing intermodal growth to give stouter stems, promoting turf density. Improves resistance to drought stress and promotes development of a darker, greener color in plants when accompanied by moderate fertility *Poa Annua reduces growth and compatibility leading to selective control after prolonged use. WILL NOT CONTROL SEED HEAD ALONE Ethylene Inhibitor ETHEPHON *Synthetic compound that decomposes into ethylene gas, which in plant metabolism, regulates plant growth and fruit/seed ripeness *Foliar absorbed *Approximately 14 21 days until maximum performance *Used to hasten fruit ripeness (apples) and/or elimination of fruit (pineapples) *Needs to be applied BEFORE seed head appears *Air temperatures should 65+ and rising *Early spring & late fall applications Plant Growth Regulator Advantages 1) Improved grass health and stress relief (energy stays in the roots instead of being used for growth, stalk, and seed production) 2) Annual bluegrass management, preventing production of seed heads and periods of flush growth. Over time, annual bluegrass WILL BE GREATLY REDUCED OR ELIMINATED. 3) Promotes the growth of one turf grass species over another (ie: slowing the growth of ryegrass during Bermuda transition, reducing competition) 4) Decrease frequency of mowing, which means dollar and manpower savings, fewer grass clippings and reduced wear and tear on mowing equipment 5) Earlier spring green up and later winter dormancy (deeper roots) 6) Thicker plant canopy fights wear and reduces soil temperatures during summer heat 3
May 8 May 18 May 24 4
June 1 5
April 4 May 18 March 6 GDD= 224 GDDTracker.net Air Temperature = 64F Soil Temperature= 40F Ethephon@ 5 oz/m 6
March 28 GDD= 436 (+212) Air Temperature = 66F Soil Temperature= 52F Ethephon@ 5 oz/m April 12 GDD= 682 (+246) Air Temperature = 63F Soil Temperature= 60F April 24 GDD= 972 (+290) Air Temperature = 60F Soil Temperature= 64F Paclobutrazol@.17oz/M May 6 GDD= 1237 (+265) Air Temperature = 58F Soil Temperature= 65F Paclobutrazol@.17oz/M June 12 Air Temperature = 88F Soil Temperature= 72F Paclobutrazol@.17oz/M June 27 Air Temperature = 70F Soil Temperature= 72F * *Increase 7
July 12 Air Temperature = 80F Soil Temperature= 78F July 26 Air Temperature = 84F Soil Temperature= 80F August 14 Air Temperature = 75F Soil Temperature= 78F August 27 (Last before Concerts 9/24 & 9/25) Air Temperature = 80F Soil Temperature= 80F October 2 (Field out of regulation) Air Temperature = 82F Soil Temperature= 78F October 26 Air Temperature = 58F Soil Temperature= 68F 8
November 14 Air Temperature = 50F Soil Temperature= 52F Ethephon@ 3.5oz/M Field Out of Regulation 9/22 Post Concert 9/26 9