Submitted to: Patent Application
Publication Type: Patent Application
Publication Acceptance Date: 8/3/1999
Publication Date: N/A
Citation: Raulston, J.R., Pair, S.D., Cabanillas, H.E. 1999. Steinernema sp. nematode for suppression of helicoverpa zea and spodoptera frugiperda. Patent Application. U.S. Patent No. 5,932,237.
Technical Abstract: A novel entomopathogenic nematode, Steinernema riobravis, was discovered in corn fields in the Lower Rio Grande Valley of Texas. The nematode was particularly the corn earworm, Heliocoverpa zea, and the fall armyworm, Spodoptera frugiperda. In field studies covering 1986-1990, it was found that natural nematode populations accounted for 49.4 and 46.1%, respectively, of all corn earworm and fall armyworm pupal mortality. In other studies infective juveniles were applied to field populations of corn earworm at the rate of 25, 50, 100, and 200 thousand nematodes per m2 resulting in, respectively, 47, 51, 66, and 72% overall mortality of prepupae and pupae. Timing of applications was critical to nematode infectivity. Parasitism of corn earworm prepupal and pupal stages exceeded 90 % when infective juveniles at the higher rates were applied to the soil and timed with either 10 % larval emergence from ears of corn or when 50% of the larvae had attained the final instar. Subsurface applications resulted in significantly higher pupal mortality than surface treatments. biocontrol agent of corn earworm and fall armyworm particularly in nursery crops such as corn where population suppression prior to their emergence and transfer to other crops is desired.