Friday, September 19, 2014

Almost-plague-level Liriope Munchers!!!

The red bricks of NCSU's campus are a nice resting pad for some grasshoppers with full bellies. 

As I walked back from lunch the other day, I stopped by the library to take a peak at a single, large grasshopper on a rail. It was a differential grasshopper (Acrididae: Melanoplus differentialis), and although I don't usually look at these common insects it was too conspicuous not to stop and admire. The next day our good friend Dave Stephan came to me to ask if I had good pics of the species. I said no, but figured "Why not?" So Dave, being the great person he is, collected some for me. The odd thing though was what they were feeding on:

A differential grasshopper sitting among the destruction it and its friends caused.

That's right, liriope or monkey grass (Liriope sp.)! This widely planted, grass-like ground cover is rarely ever attacked by pests. The most frequently encountered insect feeding on this ornamental is the fern scale, Pinnaspis aspidistrae. Otherwise I could only find reference to snails and slugs as animals that feed on this host. These grasshoppers must not know that they are not supposed to feed on it, because there were hundreds in the large patch on campus! But why? We really don't know. I am also unsure if they will feed on the related lilyturf or mondo grass (Ophiopogon sp.).

Male Melanoplus differentialis, the differential grasshopper.

Female differential grasshopper.

Differential grasshoppers are typically pests of field crops like soybean, corn and cole crops, but also feed on many grasses and other plants. They can become serious pests in some areas during certain years. Their large size (about 2" long) also makes them conspicuous and also very hungry! Keep an eye out and let us know if you notice them feeding on liriope (or mondo grass) - perhaps this is an isolated event, but we don't know for sure.