IELTS score around 6.5 puts one in a Bridge English program at University of Maryland. A 7 on IELTS is needed for full enrollment.
Three letters of recmendation are needed.
Also, “In general, our admitted students have GPA’s well above a “B” average, particularly in economics and mathematics; very high GRE’s (particularly quantitative); math preparation that includes at a minimum three semesters of calculus, a semester of linear algebra, and a semester of differential equations; and three excellent letters of reference that speak to an applicant’s potential to successfully complete a Ph.D. in economics.”
https://www.econ.umd.edu/graduate/applications-and-admissions-faq#id_math