rot stop is meant to be used b4 u get mould ,,it encourages the growth of the mould then detroys it ,,not sure if it will work on new outbreaks ,,spraying with anything late in flower can cause bud rot so using it may accelerate the condition ,,might be best to chop out the effected area ,lower humidty and get some airflow at night ,,keeping the heat up at night helps too ,,,dont smoke it