Genetic characterization of turf infesting sod webworms and their host associations

Sod webworms (Crambinae: Crambidae: Lepidoptera) are well-known pests of corn and turfgrass.  However the larval host associations of these moths in turfgrasses are poorly known in central Ohio.  Management recommendations are typically made with the assumption that resistant endophytic grasses should be used.  The identification of immature sod webworms to species using morphological characters is incredibly time consuming and only possible for a very few select species.  To better understand the host associations, species diversity, and identities we conducted regular soap flushes of two turfgrass types (Kentucky bluegrass, Poa pratensis, and creeping bentgrass, Agrostis stolonifera) from March through October of 2011 through 2013. These two types were located in Franklin Co., OH and are non-endophytic varieties of grasses known to support sod webworms.  For the 2013 season additional collections were made in a fescue mix (Festuca sp) which is an endophytic grass.  The sod webworm larvae collected were analyzed using PCR and sequences were obtained to confirm their identities.  The same genetic analysis was conducted on freshly collected adults utilizing a nightly blacklight trap at a nearby location.  In the creeping bentgrass, Parapediasia teterrella was the most commonly collected lepidoptera larvae and, to date, has been the only species crambine identified in the bentgrass.  The light trap collections found 12 species of Crambinae were common during the season.  For both years larval abundance first peaked in mid-April and then experienced a final large peak later in the summer.  The timing of the two late-summer peaks were different each year with the 2011 late-summer larval peak abundance following a large peak of adult abundance as is expected; however, the 2012 late-summer larval peak preceded the adult abundance peak.  Sod webworm larvae have been recovered from the endophytic fescue grass.