Download or read book Use of Mesotrione for Annual Bluegrass (Poa Annua L.) at Cool-season Turfgrass Establishment written by Katelyn A. Venner and published by . This book was released on 2011 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annual bluegrass is a problematic weed in highly maintained turfgrass environments, and is difficult to control due to its adaptability to highly maintained turfgrass environments and lack of highly effective chemical control options. Mesotrione is a relatively new herbicide which has been found to show some level of control of annual bluegrass, and is safe to use at cool season turfgrass establishment. Thus, mesotrione has potential to be utilized for weed control in cultivated sod production. The objectives of this research were to evaluate mesotrione to determine: 1) tolerance of selected tall fescue cultivars, an important turfgrass species cultivated for sod, to applications of mesotrione; 2) the length of residual of mesotrione versus prodiamine, bensulide and dithiopyr for control of annual bluegrass; and 3) potential of mesotrione to control winter annual broadleaf weeds at Kentucky bluegrass establishment. Tall fescue cultivars were found to be tolerant to mesotrione applications made preemergence and preemergence plus 4 weeks after emergence at higher rates than required for weed control. Significant cover reductions were only observed at the 1.12 kg ha-1 application rate of mesotrione, which is four times the highest labeled rate for weed control. There was little difference in the response of the seven tall fescue cultivars iii evaluated suggesting minor intraspecific variability between tall fescue cultivars to mesotrione. When applied to bare ground, mesotrione provided 48% annual bluegrass control in the fall and annual bluegrass control decreasing to 20% in the following spring. Prodiamine, bensulide and dithiopyr provided much greater levels of annual bluegrass control and high levels of control were maintained into the following spring. These results suggest that although mesotrione has some activity on newly germinating annual bluegrass it is much lower relative to prodiamine, bensulide and dithiopyr. Mesotrione was found to be more effective for winter annual broadleaf weed control when applied POST compared to PRE. For overall winter annual broadleaf weed control mesotrione should be applied PRE at rates of 0.21 kg ha-1 or higher and POST at 0.14 kg ha-1 or higher. The results of these studies demonstrate that mesotrione is safe for use in newly seeded tall fescue and previous studies have shown similar findings with Kentucky bluegrass. The safety of mesotrione to these two economically important turfgrass species widely grown for cultivate sod combined with its ability to control winter annual broadleaf weeds and suppress annual bluegrass demonstrate that is a new and valuable component to an overall weed control program in cultivated sod production.