This year precursors to Brood X should emerge in limited numbers in D.C., Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, Missouri, New Jersey, New York (Long Island), North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Virginia, and West Virginia. Magicicada.org has the most up-to-date map from Brood X.
Don’t panic! Yes, I’m talking to people in the afore mentioned states that do not like cicadas. Less that one percent of a Brood straggles. If you had 10,000 cicadas in your yard back in 2004, you can expect 4 or 5. 4 or 5 that are usually, quickly, eaten by birds.
In North Carolina, South Carolina and Georgia, where Brood VI will emerge for certain this year, Brood X is just west of Brood VI. Brood X hugs the western border of North Carolina & Tennessee, and Brood VI is just east of that.
What are stragglers, and why do they straggler
Stragglers are periodical cicadas that emerge in years before or after the brood they belong to is expected to emerge. Typically 17-year periodical cicadas emerge 4 years early (see the probability chart). While stragglers never seem to produce enough offspring to produce future generations, straggling is something periodical cicadas do (there’s a lot more to this, but I’m keeping it simple).
The weather is one thing that will trigger periodical cicadas to emerge early. An unusually hot fall, or hot and then cold and then hot spring, could add another “year” to what cicadas perceive as the procession of time, and so they “think”, “okay it’s been 17 years, time to emerge”, when it has only been 13 years.
Dr. Gene Kritsky, in this recent article, is quoted as saying “[c]limate changes are behind the premature debut”.
Brood VI compared to Brood X:
The data comes from Magicicada.org.