040119 504 A new report says a March survey of business supply managers is signaling solid economic growth over the next three to six months for nine Midwest and Plains states. The report issued Monday says the Mid-America Business Conditions Index hit its highest level since August, 58.2, compared with 57.9 in February. Creighton University economist Ernie Goss oversees the survey, and he says even stronger growth was hampered by international trade disputes and the global economic slowdown.