Knowledge Bank

Nymphs of 17-year cicadas, Magicicada spp., emerged from the soil on the south side of apple trees about 2 to 5 days before emergence on the north side and in the interior of nearby woods in northern Ohio. Cicadas began to emerge 2 to 3 days after 50% of the nvmphal population showed black prothoracic markings. Development of two large black spots on the prothoracic dorsum of nymphs in a field, and their emergence, occurred one day prior to that of nymphs on the south side of apple trees. The appearance of the black spots indicates that nymphs are ready to emerge from the soil.