Are two forgotten pests— grape root borer, which has a two-year life cycle, and grape scale, a sap-sucking insect that can weaken vines by extracting nutrients—holding back Arkansas grape vineyards? This question and many others will be answered at the Native and Hybrid Grape Field Day, hosted by the University of Arkansas Division of Agriculture and the Arkansas Association of Grape Growers. The event be from 1 to 6 p.m. July 28 at Rusty Tracto…