Selectivity of Methiozolin for Annual Bluegrass (Poa annua) Control in Creeping Bentgrass as Influenced by Temperature and Application Timing

Weed Science ◽  
2013 ◽  
Vol 61 (2) ◽  
pp. 209-216 ◽  
Author(s):  
Patrick E. McCullough ◽  
Diego Gómez de Barreda ◽  
Jialin Yu

Methiozolin controls annual bluegrass in creeping bentgrass but application timing and temperature could influence efficacy in turf. In field experiments, sequential methiozolin applications totaling 3.36 kg ai ha−1provided excellent (> 90%) annual bluegrass control at 8 wk after initial treatment when treatments were initiated in February/March or May but programs totaling 0.84 and 1.68 kg ha−1provided poor control (< 70%) at both timings. Methiozolin at all rates caused minimal turf injury (< 8%) but creeping bentgrass was only injured from February/March applications. In growth chamber experiments, creeping bentgrass injury from methiozolin at 10 C was 2 and 4 times greater than at 20 C and 30 C, respectively, while annual bluegrass injury was similar across temperatures. In laboratory experiments, annual bluegrass had more foliar absorption of14C-methiozolin than creeping bentgrass at 30/25 C (day/night), compared to 15/10 C, but translocation was similar at both temperatures as > 90% of absorbed14C remained in the treated leaf after 72 h. Annual bluegrass distributed and recovered more radioactivity to shoots from root-applied14C-methiozolin than creeping bentgrass while both species had about 2 times more distribution to shoots at 30/25 C than 15/10 C. Metabolites were not detected in annual bluegrass or creeping bentgrass at 1, 3, or 7 d after treatment when grown at 15/10 C or 30/25 C suggesting uptake and translocation contributes to methiozolin selectivity in turfgrass.

2009 ◽  
Vol 23 (4) ◽  
pp. 519-523 ◽  
Author(s):  
Patrick E. McCullough ◽  
Stephen E. Hart

Spray adjuvants may enhance bispyribac–sodium efficacy for annual bluegrass control but chelated iron may be needed to reduce potential turf discoloration. Field and laboratory experiments were conducted to investigate the influence of iron and adjuvants on bispyribac–sodium efficacy for annual bluegrass control in cool-season turf. In laboratory experiments,14C–bispyribac–sodium foliar absorption increased in four grasses by approximately 50 and 100% when applied with a nonionic surfactant and methylated seed oil, respectively, compared to the herbicide alone. Chelated iron did not reduce14C–bispyribac–sodium absorption. In field experiments, spray adjuvants enhanced annual bluegrass control from bispyribac–sodium at 37 g ai/ha but not at 74 g ai/ha. Iron did not reduce annual bluegrass control from bispyribac–sodium, with or without adjuvants, but mitigated creeping bentgrass discoloration for all treatments.


2011 ◽  
Vol 25 (3) ◽  
pp. 385-390
Author(s):  
Patrick E. McCullough ◽  
Stephen E. Hart ◽  
Thomas Gianfagna ◽  
Fabio Chaves

Field and laboratory experiments were conducted in New Jersey to investigate the influence of nitrogen on annual bluegrass and creeping bentgrass metabolism and responses to bispyribac-sodium. In field experiments, withholding nitrogen during the test period increased sensitivity of both grasses to bispyribac-sodium, and grasses fertilized biweekly had darker color on most rating dates. Nitrogen generally increased annual bluegrass tolerance to bispyribac-sodium at 74 g ha−1but not at 148 g ha−1. Creeping bentgrass was influenced by nitrogen at both herbicide rates. In laboratory experiments, weekly nitrogen treatments increased14C-bispyribac-sodium metabolism in both grasses compared to unfertilized plants. Annual bluegrass metabolized approximately 50% less herbicide regardless of nitrogen regime compared to creeping bentgrass. Overall, routine nitrogen fertilization appears to improve annual bluegrass and creeping bentgrass tolerance to bispyribac-sodium, which may be attributed to higher metabolism.


Weed Science ◽  
2013 ◽  
Vol 61 (2) ◽  
pp. 217-221 ◽  
Author(s):  
Jialin Yu ◽  
Patrick E. McCullough ◽  
William K. Vencill

Amicarbazone controls annual bluegrass in cool-season turfgrasses but physiological effects that influence selectivity have received limited investigation. The objective of this research was to evaluate uptake, translocation, and metabolism of amicarbazone in these species. Annual bluegrass, creeping bentgrass, and tall fescue required < 3, 56, and 35 h to reach 50% foliar absorption, respectively. At 72 h after treatment (HAT), annual bluegrass and creeping bentgrass translocated 73 and 70% of root-absorbed14C to shoots, respectively, while tall fescue only distributed 55%. Annual bluegrass recovered ≈ 50% more root-absorbed14C in shoots than creeping bentgrass and tall fescue. Creeping bentgrass and tall fescue metabolism of amicarbazone was ≈ 2-fold greater than annual bluegrass from 1 to 7 d after treatment (DAT). Results suggest greater absorption, more distribution, and less metabolism of amicarbazone in annual bluegrass, compared to creeping bentgrass and tall fescue, could be attributed to selectivity of POST applications.


2010 ◽  
Vol 24 (3) ◽  
pp. 332-335 ◽  
Author(s):  
Patrick E. McCullough ◽  
Stephen E. Hart

Bispyribac-sodium effectively controls annual bluegrass in creeping bentgrass fairways but efficacy on putting greens may be affected by management differences and thus, application regimes may need to be modified for effective annual bluegrass control. To test this hypothesis, field experiments investigated various bispyribac-sodium application regimens for annual bluegrass control on creeping bentgrass putting greens. Bispyribac-sodium regimes totaling 148, 222, and 296 g ha−1controlled annual bluegrass 81, 83, and 91%, respectively, over 2 yr. Pooled over herbicide rates, bispyribac-sodium applied two, three, and six times controlled annual bluegrass 78, 83, and 94%, respectively. The most effective bispyribac-sodium regime was 24.6 g ha−1applied weekly, which controlled annual bluegrass 90% after 8 wk with acceptable levels of creeping bentgrass discoloration. After 8 wk, all regimes reduced turf quality as a result of voids in turf following annual bluegrass control; regimes with six applications reduced turf quality the most.


2015 ◽  
Vol 29 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Jialin Yu ◽  
Patrick E. McCullough ◽  
Mark A. Czarnota

Turfgrass injury from triazines has limited the use of photosystem II (PS II) inhibitors for weed control in seashore paspalum. Amicarbazone is a new PS II inhibitor with potential safety in seashore paspalum, but the effects of application timing on turf tolerance has received limited investigation. Field experiments were conducted in Griffin, GA to evaluate the tolerance of ‘Sea Isle 1’ seashore paspalum to amicarbazone applications in winter, spring, and summer. Seashore paspalum had minimal injury (< 5%) from amicarbazone treatments (98, 196, and 392 g ai ha−1) applied for annual bluegrass control in winter and spring. By 6 wk after treatment (WAT), amicarbazone at 392 g ha−1provided 78 and 90% annual bluegrass control in 2013 and 2014, respectively, and was similar to pronamide at 1,680 g ai ha−1. Amicarbazone at 196 g ha−1provided 71% control of annual bluegrass in 2014, but control was poor (< 70%) in 2013. Sequential amicarbazone applications at 98 g ha−1provided poor control in both years by 6 WAT. From six amicarbazone rates (up to 984 g ha−1) applied in summer, seashore paspalum required 510 and < 123 g ha−1for 20% turfgrass injury (I20) and 20% clipping reduction (CR20), respectively, whereas I20and CR20measured > 984 g ha−1for ‘Tifway’ bermudagrass. Overall, amicarbazone may be safely applied to seashore paspalum in winter, spring, and summer at rates and regimens evaluated. However, seashore paspalum may exhibit shoot growth inhibition up to 4 WAT, suggesting that end users should be cautious when using amicarbazone during active growth in summer.


2016 ◽  
Vol 30 (2) ◽  
pp. 516-523 ◽  
Author(s):  
Jialin Yu ◽  
Patrick E. McCullough

Turfgrass managers can reduce foliar bleaching of smooth crabgrass from mesotrione by tank-mixing triclopyr ester with applications. These tank mixtures also have potential to enhance smooth crabgrass control compared to mesotrione alone. The objectives of this research were to evaluate the influence of triclopyr on the efficacy, absorption, and translocation of mesotrione in multitiller smooth crabgrass. In field experiments, tank-mixing triclopyr at 560 or 1,120 g ae ha−1with mesotrione at 140 g ai ha−1applied sequentially or at 280 g ha−1applied singly provided excellent control (> 90%) of multitiller smooth crabgrass in tall fescue. These treatments were more effective than mesotrione alone and fenoxaprop at 195 g ai ha−1that averaged 66 and 81% control after 6 wk, respectively. Mesotrione alone at 280 g ha−1bleached smooth crabgrass 53% at 2 wk after initial treatment (WAIT), and was 14% greater than the 140 g ha−1treatment. Sequential treatments of the low mesotrione rate bleached smooth crabgrass 16 to 22% from 3 to 5 WAIT. Triclopyr tank mixtures reduced smooth crabgrass bleaching from mesotrione on all dates to < 5%. Tall fescue injury was not detected at any evaluation date. In laboratory experiments, smooth crabgrass reached peak foliar absorption of14C-mesotrione at 24 and 168 h after treatment (HAT; 23% and 15%) when mesotrione was applied with triclopyr at 1,120 and 0 g ha−1, respectively. Triclopyr reduced translocation of radioactivity 12% at 72 and 168 HAT, compared to14C-mesotrione alone. Enhanced foliar uptake of mesotrione from triclopyr tank mixtures might improve control of multitiller smooth crabgrass compared to mesotrione alone. Reduced foliar bleaching from triclopyr is associated with less translocation of mesotrione or derivatives in smooth crabgrass.


2010 ◽  
Vol 24 (3) ◽  
pp. 326-331 ◽  
Author(s):  
Patrick E. McCullough ◽  
Stephen E. Hart

Bispyribac-sodium selectively controls annual bluegrass in cool-season turf but efficacy may be influenced by management practices, such as plant growth regulator use. Experiments were conducted in New Jersey to investigate efficacy and absorption of bispyribac-sodium applied with trinexapac-ethyl for annual bluegrass control and turfgrass tolerance. In laboratory experiments with annual bluegrass, creeping bentgrass, and perennial ryegrass, tank-mixing trinexapac-ethyl with14C-bispyribac-sodium increased presumed foliar absorption of14C-bispyribac-sodium compared with nontrinexapac-ethyl treated; absorption increased with trinexapac-ethyl rate. Differences in14C-bispyribac-sodium absorption were not detected among emulsifiable concentration, microencapsulated concentration, and wettable powder trinexapac-ethyl formulations. In field experiments, sequential bispyribac-sodium applications controlled annual bluegrass 93%, but trinexapac-ethyl did not affect efficacy. Tank-mixing all trinexapac-ethyl formulations with bispyribac-sodium provided similar annual bluegrass control and creeping bentgrass quality compared with bispyribac-sodium alone. Applications of bispyribac-sodium reduced dollar spot cover in both years, whereas trinexapac-ethyl reduced dollar spot cover only in 2005.


HortScience ◽  
2008 ◽  
Vol 43 (7) ◽  
pp. 2252-2255 ◽  
Author(s):  
Robert R. Shortell ◽  
Stephen E. Hart ◽  
Stacy A. Bonos

Annual bluegrass (Poa annua L.) is a problematic weed in Kentucky bluegrass (Poa pratensis L.). Bispyribac-sodium herbicide can effectively control established annual bluegrass in other cool-season turfgrasses, but unacceptable injury to Kentucky bluegrass has been reported. However, only a few Kentucky bluegrass cultivars have been evaluated. The objective of this study was to determine the extent of intraspecific variability among Kentucky bluegrass cultivars and selections to sequential applications of bispyribac-sodium herbicide. Field experiments were conducted in 2004 and 2005 in New Jersey to determine the response of 55 Kentucky bluegrass cultivars and selections to bispyribac-sodium. The herbicide was applied at 188 g·ha−1 followed 3 weeks later by a second application of 281 g·ha−1. Kentucky bluegrass injury ranged from 8% to 93% 8 weeks after initial treatment (WAIT). ‘Blackstone’, ‘Serene’, and A98-962 were the most tolerant to bispyribac-sodium, exhibiting less than 20% injury 8 WAIT. Conversely, ‘Washington’, 95AN-10, and ‘Avalanche’ were the most susceptible with up to 93% injury 8 WAIT. The range in tolerance to bispyribac-sodium within Kentucky bluegrass indicates the potential for the identification and development of cultivars with improved tolerance to bispyribac-sodium herbicide.


2012 ◽  
Vol 26 (4) ◽  
pp. 789-792 ◽  
Author(s):  
Patrick E. McCullough ◽  
Diego Gómez De Barreda

Methiozolin selectively controls annual bluegrass in cool-season turfgrasses, and practitioners may wish to reseed desirable species in treated areas. Field experiments were conducted to evaluate reseeding intervals for creeping bentgrass, perennial ryegrass, and tall fescue following methiozolin applications. Turfgrass establishment varied for species, application timing (0, 2, 4, or 6 wk before seeding, WBS), and rates tested (0.56, 1.12, or 2.24 kg ai ha−1). Reductions in turf cover suggest that seeding of creeping bentgrass, perennial ryegrass, and tall fescue should be delayed 2 wk after methiozolin treatments at 0.56 kg ha−1. However, reseeding should be delayed after methiozolin treatments at 1.12 kg ha−1for approximately 4, 4, and 2 wk for creeping bentgrass, perennial ryegrass, and tall fescue, respectively. Similarly, establishment was reduced on all dates from the nontreated after 2.24 kg ha−1was applied at 4 WBS, suggesting that reseeding should be delayed for at least 6 wk on all three species at the high rate.


Weed Science ◽  
2015 ◽  
Vol 63 (2) ◽  
pp. 539-545 ◽  
Author(s):  
Diego Gómez de Barreda ◽  
Rashmi Singh ◽  
Sudeep S. Sidhu ◽  
Patrick E. McCullough

Common lespedeza is a problematic summer annual weed in bermudagrass lawns, with limited PRE herbicides available for control. Dithiopyr is a pyridine herbicide primarily used for PRE grassy weed control but has shown potential efficacy for controlling annual legumes. The objectives of this research were to evaluate efficacy and behavior of dithiopyr in common lespedeza. In a 3-yr field experiment, sequential dithiopyr applications at 0.42 or 0.56 kg ai ha−1beginning in late winter and single applications of dithiopyr at 0.56 kg ai ha−1in spring controlled common lespedeza ≥ 88%. Single and sequential applications of indaziflam at 0.035 and 0.053 kg ai ha−1provided poor control (< 70%) of common lespedeza by late summer. In laboratory experiments, bermudagrass and common lespedeza had similar foliar absorption of14C-dithiopyr, averaging 10% of the14C applied, and both species retained > 80% of14C in the treated leaf at 72 h after treatment (HAT). Common lespedeza translocated 6 times more root-absorbed14C to shoots than bermudagrass and had 2.8 times greater absorption (Bq mg−1) at 72 HAT. In metabolism experiments, parent herbicide levels measured ≥ 84% of extracted14C in both species at 1, 3, and 7 d after treatment. Overall, dithiopyr effectively controls common lespedeza in bermudagrass as a PRE treatment in spring. Susceptibility of common lespedeza to dithiopyr is associated with acropetal translocation and greater herbicide concentrations compared with a tolerant species, bermudagrass.


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