SELECTIVE PREEMERGENCE
See preemergence herbicides listed for annual grasses.
SELECTIVE POSTEMERGENCE
amicarbazone (Xonerate Herbicide EPA#66330-46)
Oregon only
Rate 3 to 29 fl oz/A Xonerate (See label for specific turfgrass rates and recommendations) Per label: 1.0 to 10.0 oz/A
Time Apply for selective postemergence and some preemergence control of certain weeds in established turfgrasses.
Remarks Xonerate is a 70% WDG. Controls annual bluegrass in established creeping bentgrass, Kentucky bluegrass, fine fescues, tall fescues, and perennial ryegrass.
Caution Generally, apply Xonerate at air temperatures ranging from 55° to 80°F. Do not make applications when temperatures are expected to drop below 55°F. For specific turfgrass recommendations regarding temperature and application please consult the label. Do not apply if soil pH is above 7.4. Do not apply more than 10.25 oz/A in one application or per year. Do not apply to sites where annual bluegrass is maintained as a desirable turfgrass. Xonerate does not control perennial broadleaf weeds in turfgrasses. Apply with labeled tank-mix partners in a minimum of 20 gal/A of spray volume using broadcast boom equipment. Read label carefully for additional precautions about turfgrass establishment, application timing and intervals. Overlap of application can cause turf damage.
Site of action Group 5: photosystem II inhibitor
Chemical family Triazolinone
*Not Registered in CA or WA
bispyribac-sodium (Velocity PM POA Management Herbicide EPA# 59639-258)
Registered in Idaho, but not WA or OR
Rate 2.25 fl oz/A or 30 gal ai/A (0.066 lb ai/A). For slower, steady conversion to creeping bentgrass: make 5 applications at 0.75 fl oz/A on a 14-day interval. For aggressive conversion to creeping bentgrass or perennial ryegrass: Make 2 applications at 2.25 fl oz/A on a 14- to 21-day interval.
Time Apply when grass is actively growing. Control is better when air temps have consistently reached mid to high-60sF in the spring.
Remarks Velocity may mildly discolor creeping bentgrass and perennial ryegrass. Discoloration begins 3 to 10 days after application. Vigorously growing grasses should outgrow symptoms within 3 to 14 days. If temporary turf chlorosis is a concern, avoid treating small patches of turf that are surrounded by untreated areas of turf. Velocity performs best under sunny conditions when daytime temperatures are 65 to 80°F during and after application.
Caution Do not apply Velocity to turfgrass with symptoms of heat stress or if significant heat stress is expected. Velocity may increase the susceptibility of creeping bentgrass to Pythium blight when conditions are favorable for infection. Do not apply to creeping bentgrass or perennial ryegrass mowed to less than 0.375 inch. Do not apply to golf greens and roughs. Velocity may not be effective against all biotypes of annual bluegrass.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Pyrimidinylthiobenzoate
ethofumesate (POACONSTRICTOR HERBICIDE EPA# 94396-1; Prograss Herbicide EPA# 432-1462; Prograss SC Herbicide EPA# 432-1462)
Rate New seedings applied preemergence of weeds: use 0.2 to 3 pints/A. Postemergence applications: use 2.25 to 3 pints/A no later than the 4-leaf stage of the weed. Harder-to-control weeds must be treated by the 2-leaf stage of the plant. For established grasses: use 2.25 to 3 pints/A both pre- and postemergence for perennial ryegrass and tall fescue. Labels give rates for each type of grass and season of application.
Time Apply to grasses listed as tolerant on label, before annual bluegrass reaches the 4-leaf stage.
Remarks Effective only in a series of three or more treatments; single treatments are not effective. Some perennial strains of annual bluegrass may not be affected.
Caution Kills fine fescues and roughstalk bluegrass and causes unsightly injury to most bentgrasses. Assess components of the turf carefully before beginning treatment.
Site of action Group 15: very long-chain fatty acid synthesis inihibitor
Chemical family Benzofuran
SELECTIVE GROWTH SUPPRESSION
paclobutrazol (TRIMMIT 2SC PGR /TURFGRASS EPA# 100-1014, TRIMMIT 2SC PGR /TURFGRASS EPA# 100-1014)
Rate Use 0.25 to 0.50 lb ai/A. If annual bluegrass is a significant portion of the population, it would be a good idea to reduce the application rate by 50%. Two additional sequential applications 8 weeks apart are allowed (for a total of 3 applications) per year.
Remarks Available in liquid (2SC). Selectively suppresses annual bluegrass growth, allowing tolerant grasses to dominate turf. Long-term success requires annual re-treatment. Tends to be more effective in turf mainly with annual Poa annua biotypes. Paclobutrazol is labeled for use on bentgrass, Kentucky bluegrass, and perennial ryegrass.
Caution Not recommended for turf with more than 70% annual bluegrass. Do not use during periods of extreme environmental stress (e.g., heat, cold, drought). At high rates, Kentucky bluegrass and bentgrass turf may be discolored temporarily.
Site of action Gibberellin biosynthesis inhibitor
Chemical family Class B plant growth regulator
SELECTIVE SEED HEAD SUPPRESSION
ethephon (PROXY GROWTH REGULATOR EPA# 432-1230; Verve PGR EPA# 228-660; Ethephon 2 Plant Regulator EPA# 66330-262; QUALI-PRO ETHEPHON 2 SL EPA# 66222-151; Helena Oskie Plant Regulator EPA# 5905-595)
Rate 5 fl oz in 1 to 2 gal water/1,000 sq ft. See label for specific application intervals. Per Helena Oskie Plant Regulator label, rate is 3 1/3 fl oz per 1,000 sq ft
Time Apply to golf, parks, and sports turf. Not for residential use.
Remarks Only Proxy lists golf, parks or sports turf. Only golf turf is listed on other labels. Proxy is used to suppress seed head formation in Poa annua and white clover, among others, and also to suppress growth of certain cool-season grasses. It is foliar-absorbed and is most effective on actively growing, healthy turf. Apply in a sufficient volume of water to provide uniform coverage. Proxy is rainfast in 2 hours. A spreader/sticker is not necessary. Do not reenter treated area until dry. Delay mowing until the day after the application.
Caution Do not treat turfgrasses with poor root systems, or those growing under stress due to poor soil conditions. Do not use if thatch is excessive. Do not apply Proxy through any type of irrigation system. Mix only the amount of product you expect to use each day. Do not allow mixed solution to stand overnight. Scalping may occur on creeping bentgrass cultivars after more than two applications of Proxy for Poa seed head suppression.
Site of action Enhances release of ethylene gas
Chemical family Phosphonic
TURFGRASS GROWTH SUPPRESSION
maleic hydrazide (Drexel Sprout-Stop EPA# 19713-2)
Rate 3.0 lb of product/1,000 sq ft Per label: 1.75 to 2.25 gal/A (2.25 lb Maleic hydrazide equivalent per gallon)
Time Apply this product to green grass, since brown grass will not absorb the spray. Use of this product is limited to one application per year made either in the Fall or the Spring followed by correct maintenance procedures to produce required turf growth control.
Remarks For spring application (April 15 to June 1) use 1.75 gal product in 50 gal water/A to reduce or eliminate mowing. For fall applications, (Oct. 1 to Nov. 15) use 2.25 gal of this product in 50 gal water/A to reduce growth next season. The fall treatment should also be applied to green grass before it becomes dormant.
Caution Do not apply during the summer since most permanent grasses become partially dormant in the summer. This product should be applied at temperatures below 85°F under high temperatures and low humidity conditions, this product will crystallize on the leaf surface preventing normal absorption into the plant. To obtain the desired results, the plants should not be stressed from either too much or too little water before or after application. Make only one application per season.
Site of action mitotic inhibitor
Chemical family Class C plant growth regulator
trinexepac-ethyl (Game Up EPA# 34704-1005; Groom PGR EPA# 83070-4; PRIMO MAXX PGR /TURF EPA# 100-937; PODIUM PGR /TURF EPA# 100-937)
Rate Rate varies depending upon the product, turfgrass species, mowing height and length of suppression desired.
Time Apply to actively growing grass, including home lawns, parks, recreation areas, golf course roughs, cemeteries, business sites, sports fields, and sod farms that are not under stress.
Remarks Primo MAXX reduces mowing frequency and the amount of grass clippings. It also increases turfgrass density, color, and quality. Useful in difficult-to-mow areas; can minimize the need to edge along sidewalks, curbs, parking lots, driveways, flower beds, and fences and around posts, storage sheds, and trees. Primo MAXX reaches the growing point by foliar uptake and is rainfast after 1 hr. Water is not needed to activate it.
Caution Any cultural practice that affects turf growth and vigor will influence turf response to Primo MAXX. Rates in the table on the label provide about 50% growth inhibition over a 4-week period with little or no discoloration. With less-than-optimal growth conditions, rates may have to be reduced by 50% due to stress. Multiple applications of Primo MAXX can be made each growing season, but do not exceed a total of 7 fl oz/1,000 sq ft per year. If turf is going into dormancy due to high or low temperatures or lack of moisture, reduce Primo rate. To minimize turf injury, apply Primo MAXX, then wait at least 4 hr before mowing; or mow first, wait at least 1 hour, then apply Primo MAXX.
Site of action Late gibberellin (GA1) biosynthesis inhibitor
Chemical family Class A plant growth regulator
prohexadione calcium (Anuew Turf Growth Regulator EPA# 1001-91(Not registered in WA) ; Anuew EZ EPA# 1001-92)
Registered in Idaho, Not registered in OR & WA.
Rate Varies depending upon the product, turfgrass species, mowing height and intensity of suppression desired.
Time Apply to actively growing grass, including home lawns, parks, recreation areas, golf course fairways, tees, greens, roughs, cemeteries, business sites, sports fields, and sod farms that are not under stress.
Remarks Anuew reduces mowing frequency and the amount of grass clippings. It also increases turfgrass density, color, and quality. It is useful in difficult-to-mow areas and can minimize the need to edge along sidewalks, curbs, parking lots, driveways, flower beds, and fences and around posts, storage sheds, and trees. Primo MAXX reaches the growing point by foliar uptake and is rainfast after 1 hr. Water is not needed to activate it. When mixing in hard water (140 ppm and higher) add ammonium sulfate to the tank first at 1 lb for every 1 lb of Anuew or 1 lb for every 1 pint of Anuew EZ.
Anuew can be used at higher rates to intensely suppress annual bluegrass growth and provide the competitive edge to more desirable turfgrass species such as creeping bentgrass, Bermudagrass, and tall fescue. Anuew can also be mixed with ethephon in the spring to enhance annual bluegrass and zoysiagrass seedhead suppression and quality.
Anuew can be used to slowly transition from ryegrass to Bermudagrass in the spring while also providing excellent annual bluegrass suppression.
Site of action Late gibberellin (GA1) biosynthesis inhibitor
Chemical family Class A plant growth regulator