Periodical cicadas are emerging in large numbers in various areas of the southern two-thirds of the state. Last week in this newsletter, I predicted emergence in early June to correspond with emergences in the past. I wasnít sure whether the early spring we are having would affect underground insects such as periodical cicada nymphs, particularly ones with a 13-year cycle. But like most everything else we are seeing, these cicadas started emerging about two weeks early.
Iíve received reports of large numbers in Jefferson, Effingham, Massac, Marion, Macon, Madison, Williamson, Macoupin, Montgomery, and Sangamon counties. My thanks to David Robson, Extension Educator, and numerous Unit Extension Office secretaries that provided this information. Large numbers of finger-sized holes appearing on the soil surface, sometimes with short chimneys around them, are likely to be emergence holes of cicada nymphs.
These insects do little damage to established trees but cause numerous dead and broken branch tips with brown leaves. Several insecticides kill the insects on contact but will not provide enough residual control to prevent egg-laying damage. Trees with trunks less than two inches in diameter should be protected with netting or tree wrap.