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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #291202

Title: Effect of eastern gamagrass on fall armyworm and corn earworm development

item Ni, Xinzhi
item PATEL, ANSHULI - University Of Georgia
item TOEWS, MICHAEL - University Of Georgia
item BUNTIN, G. DAVID - University Of Georgia

Submitted to: Entomological Society of America Regional Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 2/10/2013
Publication Date: N/A
Citation: N/A

Interpretive Summary: not required

Technical Abstract: The fall armyworm, Spodoptera frugiperda (J.E. Smith) and the corn earworm, Helicoverpa zea (Boddie) are two important corn pests in the southern U.S. states. Effect of the leaves from the corn relative, the Eastern gamagrass (Tripsacum dactyloides L.) on fall armyworm and corn earworm development was examined under the laboratory conditions using both excised leaves and artificial diet bioassays. The leaf feeding bioassay was conducted using a neonate larva in a Petri dish. The leaves from the Eastern gamagrass and six corn inbred lines (i.e., corn inbreds ‘AB24E’ as susceptible control,‘Mp708’ as resistant control, ‘FAW7050,’ ‘FAW7061,’ ‘FAW7111,’ and ‘Red Dent’) were used in the study. The leaf-feeding bioassay was repeated three times with 10 larvae per replication. The artificial diet bioassay was conducted by including 10% of the ground freeze-dried gamagrass leaves into the artificial diet. The diet bioassay was conducted with 15 insects per replication, and the bioassay was repeated three times. The leaf-feeding bioassay showed that the feeding on the Eastern gamagrass caused 100% mortality for the corn earworm, and 53% mortality for the fall armyworm. Among the seven types of excised leaves used in the experiment, the weight from the fall armyworm larvae fed on the Eastern gamagrass leaves was the lowest (0.01 ± 0.001g, n = 14), whereas the fall armyworm larvae fed on the susceptible control corn leaves AB24E had the highest weight (0.1 ± 0.02g, n = 18). When compared with the control of the artificial diet, the addition of the freeze-dried Eastern gamagrass leaves in the artificial diet significantly reduced larval weight of both fall armyworm and corn earworm, but did not affect the mortality of the larvae during the 7-d experimental period. Both bioassays showed that the Eastern gamagrass leaves suppressed larval development of both fall armyworm and corn earworm.