Tenacity is only going to suppress poa annua when used as a pre-emergent for it. You would really only use Tenacity as a pre-emergent over the entire lawn if you are needing a pre-emergent to use at the same time as seeding or over-seeding. Otherwise, ProGrass would be a better choice for poa annua control and for use on established perennial ryegrass.
No Tenacity is not labeled for Hippuris Vulgaris (Mares tail). Crossbow Herbicide is labeled for marestail. Please refer to the product label for complete application instructions.
Tenacity Herbicide is our most popular product for eliminating bentgrass from other desirable turfgrasses, but it does typically require multiple applications. Late summer/fall applications will be more effective than spring applications. If you are able to spot treat with RoundUp QuikPro, that is another option. It would still be ideal to wait at least 10-14 days after applying the Roundup QuikPro before raking out the dead plants and re-seeding those areas.
Tenacity Herbicide is safe to be used only on dormant Bermuda lawns. Please refer to the product label for application instructions and mix rates.
