Plectris pusio is a species of beetle of the family Scarabaeidae. It is found in Brazil.
Adults reach a length of about 7.5 mm. They are light reddish-brown. The upper surface is sparsely covered with short, appressed setae. On the elytra, some stronger, erect scale-like setae are found, especially on the lateral margins. The underside is covered with short, fine, appressed setae.