Blackberry and Raspberry
Your advice suggests not planting raspberry plants within 300 feet of wild blackberries. What makes wild ones different than new ones planted? How about blueberries?
Certified GKH Gardening Expert
Wild blackberries can carry fungus and viruses that can make your raspberries sterile (more information here: https://www.gardeningknowhow.com/edible/fruits/blackberries/blackberries-not-fruiting.htm. Ones you buy from the store should be certified virus and fungus free. This problem does not affect blueberries.