Controlling Annual (Poa Annua) and Roughstalk Bluegrass (Poa Trivialis) in Cool Season Lawns with Methiozolin B

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Controlling Annual (Poa annua) and Roughstalk Bluegrass (Poa trivialis) in Cool Season Lawns with Methiozolin B. McNulty and S. Askew Virginia Tech Turfgrass Weed Science Outline

 About Annual and Roughstalk Bluegrasses  Methiozolin (MRC-01)  Objectives  Methods and Materials  Results  Summary/Conclusion About the Species  Annual and roughstalk bluegrasses are grassy weeds that commonly infest home lawns in the United States.  Roughstalk can resemble annual, but has stolons and is a perennial  Annual bluegrass is a prolific seed producer Methiozolin  New herbicide developed and produced by the Moghu Research Center in South Korea.  Isoxazoline class of chemistry  Believed cell wall biosynthesis inhibitor  Offers PRE and POST control of annual (and roughstalk??) bluegrass(es). (http://www.alanwood.net/pesticides/me thiozolin.html)  Safe  Registered in Korea, seeking US labeling  Formulated as 25% EC Objectives  Evaluate rates and programs of methiozolin for selective control of annual bluegrass and roughstalk bluegrass in cool season turfgrasses.  Compare performance of MRC-01 to industry standard, bispyribac-sodium (Velocity). Trial Locations  Three trials initiated at the Glade Rd. Research Facility in Blacksburg, VA. on April 19, 2010

 First Site – Perennial ryegrass (PR) (Lolium perenne) infested with both bluegrasses and white clover (Trifolium repens)  Second Site – Kentucky Bluegrass (KBG) (Poa pratensis) contaminated with white clover  Third Site –Tall fescue (TF) (Festuca arundinacea) Methods and Materials  Treatments replicated 3 times using RCBD  Plot Size – 1m x 3m????????????

 CO2 pressured backpack sprayer calibrated at 280 L/ha  Methiozolin @ 500, 1000, 1500, 2000, 3000, and 4000 g ai/ha  Bispyribac-sodium at 74 g ai/ha  Non-treated check  M2000- & Vel. 2x, 4WAIT Methods and Materials  Ratings taken every 2 weeks at all trial locations

 Rated items at each location:  PR – Cover/control of both bluegrasses and clover, seedhead, injury, cover PR  KBG – Cover and injury KBG, clover control and cover  TF – Cover and injury of TF

 Data subjected to Fisher’s Protected LSD, P=.05 Results Kentucky Bluegrass Injury 2WAIT

45 a

Percent Injury Percent 15

5 b b b b b b b

0 MRC 500g MRC 1000g MRC 1500g MRC 2000g MRC 3000g MRC 4000g Veloc. 74 g NTC

LSD = 4.73 Velocity Injury on KBG 2WAIT Annual Bluegrass Seedhead Suppression 2WAIT a a 100 a

90 a

50 Suppression (%) 40 b b 30

20 Seedhead

10 c c

0 MRC 500g MRC 1000g MRC 1500g MRC 2000g MRC 3000g MRC 4000g Veloc. 74 g NTC

LSD = 17.71 Seed-head Suppression 2WAIT White Clover Control 7 WAIT a

100

Percent Control Percent 30

10 b b b b b b b

0 MRC 500g MRC 1000g MRC 1500g MRC 2000g MRC 3000g MRC 4000g Veloc. 74 g NTC

LSD = 2.23 Annual Bluegrass Control 8 WAIT a 100 a a 90 a

70 b

50 c 40

Percent Control Percent 30

20 d 10 d

0 MRC 500g MRC 1000g MRC 1500g MRC 2000g MRC 3000g MRC 4000g Veloc. 74 g NTC

LSD = 20.44 Roughstalk Bluegrass Control 4WAIT

100 a a a

70 b

60 b

40 c

Percent Control Percent 30

20 d 10 d

0 MRC 500g MRC 1000g MRC 1500g MRC 2000g MRC 3000g MRC 4000g Veloc. 74 g NTC

LSD = 12.59 Summary  MRC-01 is safe to all three turf types tested at all rates, but lacks control of white clover  Bispyribac-sodium seriously injures KBG, but superior clover control  MRC-01 provides better annual bluegrass control than bispyribac-sodium  MRC-01 and bispyribac-sodium are equivalent in roughstalk bluegrass control  Both MRC-01 and bispyribac-sodium provide excellent annual bluegrass seed-head suppression Questions?