The Parkdale High School Symphonic Band, which has earned superior ratings at Prince George's County and Maryland state band competitions, has been selected by audition to give two Mother's Day Concerts May 11 at Expo '86 in Vancouver, British Columbia.

The band's director, Steven Theodore, who has directed the group for the past two years and who has been a music teacher in the county for 14 years, said the young musicians are attending extra rehearsals before school and in the evening to prepare for the exposition.

The band's program will feature a medley from Leonard Bernstein's "West Side Story", a medley of Civil War tunes by Clare Grundman, an overture by Caesar Giovannini, a flute solo by Penny Russell of Claude Bolling's "Suite for Flute and Jazz Piano", and a clarinet solo by Tom Leverance of Carl Maria von Weber's "Concerto No. 2 for Clarinet." The band will also play some marches and will end with "America the Beautiful."

Theodore said the band raised $10,000 toward the cost of the trip by selling flowers, pizzas and other items through the school year. The band, located in Riverdale, is the only Washington area band to be invited to the world exposition. U-Md. Professor

Elected Elizabeth S. Prather, a professor of food, nutrition and institutional administration at The University of Maryland, College Park campus, was elected chairman of the first State Board of Dietetic Practice of Maryland. The board, established in 1985, sets guidelines for professional dietitians. Easter Seal Prize-Winner

Bowie resident Judy Colbert is the recipient of a 1985 communications award from the National Easter Seal Society for her article on post-polio syndrome, written in conjunction with the society's National Handicap Awareness Week. The award program recognizes outstanding reporting that contributes to public understanding of conditions that affect disabled people. 2 Air Cadets Win Award

Two cadets from the Civil Air Patrol's Prince George's squadron recently received an award for achievement in the cadet program. The award, named for Army aviation pioneer Billy Mitchell, went to Eleanor Roosevelt High School students Steven B. Feeney, a senior, and Christopher R. Dewey, a junior. Student in Honor Society

Claire Kelly, daughter of Anne T. Kelly of Hyattsville, has been accepted into Alpha Sigma Nu, a national Jesuit scholastic honor society for college juniors and seniors who maintain grade point averages of at least 3.0. Kelly is a student at Wheeling College in West Virginia. Employe of the Year

Doris Coward of Suitland has been named the U.S. Senate Service Department's employe of the year in recognition of her outstanding work performance as a bindery machine operator. She has worked for the department since 1974. Temple Hills Princess

Christina Denise Cicala of Temple Hills represented Maryland as a cherry blossom princess in the National Cherry Blossom Festival. Cicala is to graduate in May from the University of Maryland.