"Boron applications of 0.5 and 1.0 lbs boron per acre are effective in preventing internal damage above 2% if applied uniformly prior to 60 days after planting." 1
1- Morrill, L., W. Hill, L. Ashlock, L. Tripp, B. Tucker and L. Weatherly. 1977. Boron Requirements of Spanish Peanuts in Oklahoma: Effect of yield and quality and interaction with other nutrients. Oklahoma State University Agricultural Experiment Station.