I have a neighbor that is going to spray Roundup to kill the weeds/small brush on about 5 acres near my bee yard. does anyone know if this may be hazzardous to my hives as 2 are about 50 yards from this spot. the hives in question are in his garden. the temps here have been 80 to 90 degrees and humid so closing the hives up is out of the question. he plans to do this Tuesday afternoon.