Fall Armyworm (lepidoptera: Noctuidae) Resistance in Texas Bluegrass, Kentucky Bluegrass, and Their Hybrids ( Poa Spp.)

The fall armyworm Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a destructive pest of many species of both C3 and C4 (cooland warm-season) turfgrass. No-choice experiments were conducted to evaluate 13 turfgrass genotypes of various Poa spp. for susceptibility or resistance to the fall armyworm. All 13 genotypes, including 8 Texas bluegrass ( Poa arachnifera Torr.), 2 Kentucky bluegrass ( P. pratensis L.) and 3 Kentucky bluegrass × Texas bluegrass interspecies hybrids, were antibiotic and produced an accumulated >80% mortality of neonate larvae before they pupated. ‘Reveille’ (a hybrid) provided 100% antibiosis of larvae within 4 d of feeding. When 4-d-old fall armyworm larvae that had first fed on a susceptible Poa host were confined on the same 13 Poa genotypes as in the neonate test, a much higher survival rate was recorded. ‘Reveille’ produced 94.4% mortality after 3 d of feeding and 100% mortality after 8 d of feeding, while TXKY90-13-16 (another hybrid) provided 100% mortality of larvae within 13 d of feeding. A third hybrid, TXKY90-13-8 was one of the more susceptible genotypes. For the 4-d-old larvae, ‘Baron’ and ‘Delwood Fine’ Kentucky bluegrass provided only 50 and 22.2%, respectively, mortality after 8 d of larval feeding and did not produce 100% mortality until pupation. Also, mortality of larvae on the 8 Texas bluegrass genotypes produced ≤ 45% maximum accumulated mortality by pupation or adult emergence. ‘Laser’ rough bluegrass ( P. trivialis L.) is an excellent host with ≤ 5.6% larval mortality.