Eraser A/P can be sprayed around trees and should not harm them as long as you are not spraying the foilage or roots directly.
Eraser A/P has no residual soil activity and you would be fine to plant in the treated area as soon as 2 weeks after application.
The ratio of Eraser A/P for black locust is 1.3 - 2.7 oz. per gallon of water.
We would not recommend for you to use Eraser A/P because the active ingredient is Glyphosate which is non-selective and it will kill everything you spray with it. We would recommend SedgeHammer Herbicide because it is safe for your Bermudagrass and it targets Nutsedge specfically or Dismiss Turf Herbicide, it is also labeled safe for Bermudagrass and targets Nutsedge and other labeled weeds as well.
Eraser A/P needs to be applied at least 4-6 hours before you are expecting any rain.
Yes, Eraser A/P is labeled for sand burrs as a post emergent at a rate of 1 1/3 - 2 2/3 oz per gallon of water. Also we would suggest that you take a soil sample to your local extension office or master gardener to check the soil quality as well.
Eraser A/P is comparable to Roundup and could harm turf grass. Be sure to apply on a less windy day as you spot treat.
Eraser A/P should be applied when weeds are actively growing. When making applications in low relative humidity, set up equipment to produce larger droplets to compensate for evaporation. Droplet evaporation is most severe when conditions are both hot and dry.