Show useful ala plants gjul run wild and become grave ad DAL pests there aau numerous nume roua suni cases where ful plants have q become weeds because they were moved alu pa to 01 places where conditions were favorable for their rapid spread putt nd Aop development dolo ment johnson grass is very siai useful tit in the south to 01 protect the sides saple 0 of levees much sit as quack grass pun and western flient grass was sum formerly used POST to 01 protect railway embankments once introduced into cultivated fields where oolf tho hoota are widely scattered by machinery the neove useful grasses sas in at once become serious pests |