The Czech combination, the Pliskova sisters Karolina and Kristyna, beat Erakovic and her Slovakian partner Andreja Klepač 6-4 7-5.
Last week Erakovic reached the singles semi-finals of the Washington Open, before losing to Japan's Kurumi Nara.
Erakovic dominated the opening set, winning 6-0 - before Nara came back to win the next two 6-4 6-4.
Nara bowed out in the final to the sixth seed Svetlana Kutsnetzova, who defeated her Russian compatriot Ekaterina Makarova in the other semi-final before beating the Japanese 6-3 4-6 6-4.
