After the wettest May on record, mosquito populations are expected to be very large. Besides using sprays with DEET, other measures can be used in the backyard.
Dr. Richard Merritt, chairman of MSU's Entomology Department says certain sprays and foggers can set up a mosquito barrier around your patio for a few hours. Some tiki torches and other products that burn slowly give off odors that mosquitoes don't like.
Products like bug zappers, co2 traps, electronic buzzers and high frequency gear are not useful against mosquitoes, and although birds and bats do eat the insects they are just as likely to make a meal out of the first bug they meet.