Monday, December 10, 2007 - 10:41 AM

Role of leaf sheath toughness, lignification and anatomy in resistance of St. Augustinegrasses against southern chinch bug, Blissus insualris Barber (Hemiptera: Blissidae)

Murugesan Rangasamy, muruent@ufl.edu1, Bala Rathinasabapathi, brath@ufl.edu2, Heather J. McAuslane, hjmca@ufl.edu3, Ronald H. Cherry, Pinesnpets@aol.com4, and Russell Nagatta, nagata@ifas.ufl.edu4. (1) University Of Florida, Department of Entomology and Nematology, PO Box 110620, Gainesville, FL, (2) University Of Florida, Horticultural Sciences Department, 1143 Fifield Hall, PO Box 110690, Gainesville, FL, (3) University of Florida, Entomology and Nematology, P.O. Box 110620, Gainesville, FL, (4) University Of Florida, Everglades Research and Education Center, 3200 E. Palm Beach Rd, Belle Glade, FL

Southern chinch bug, Blissus insularis Barber, is a serious insect pest of St. Augustinegrass, Stenotaphrum secundatum (Walt.) Kuntze in Florida and other Gulf Coast States. Resistance to southern chinch bug has been identified in St. Augustinegrass lines such as ‘FX-10’ and NUF-76. Previous studies showed high level of antixenosis in FX-10 and moderate level of antixenosis and possible antibiosis in NUF-76. This research investigated the role of leaf sheath lignifications and anatomical differences in southern chinch bug resistant St. Augustinegrasses. A susceptible polyploid “Floratam” and diploid “Palmetto” varieties have been included in the study for comparisons. Both FX-10 and NUF-76 had significantly higher number of stylet probes on the outer leaf sheath than did susceptible lines. The chinch bug stylet reached the innermost layer of the leaf sheath less frequent on FX-10 than on Floratam. Anatomical studies showed a higher number of sclerenchyma cells around the phloem in FX-10 than in Floratam which could positively be correlated with the high level of resistance to southern chinch bug.

Species 1: Hemiptera Blissidae Blissus insularis (southern chinch bug)