Effect of Sorghum Webworm on Yield of Grain Sorghum in Oklahoma12

H. G. Kinzer; C. F. Henderson

doi:10.1093/jee/60.1.118

Effect of Sorghum Webworm on Yield of Grain Sorghum in Oklahoma12

Journal of Economic Entomology ◽

10.1093/jee/60.1.118 ◽

1967 ◽

Vol 60 (1) ◽

pp. 118-121

Author(s):

H. G. Kinzer ◽

C. F. Henderson

Keyword(s):

Grain Sorghum ◽

Sorghum Webworm

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Influence of Panicle Maturity on Infestation of Grain Sorghum by Corn Earworm and Sorghum Webworm (Lepidoptera: Noctuidae) in Georgia

Journal of Entomological Science ◽

10.18474/0749-8004-26.4.419 ◽

1991 ◽

Vol 26 (4) ◽

pp. 419-424

Author(s):

J. R. Chamberlin ◽

J. N. All

Keyword(s):

Helicoverpa Zea ◽

Paired Comparison ◽

Larval Density ◽

Field Tests ◽

Grain Sorghum ◽

Corn Earworm ◽

Egg Parasitism ◽

Low Levels ◽

Sorghum Webworm ◽

Lepidoptera Noctuidae

The influence of panicle maturity on oviposition by the corn earworm, Helicoverpa zea (Boddie), and sorghum webworm, Celama sorghiella (Riley), was investigated on grain sorghum in Georgia during 1986 and 1987. Stage of panicle development, density of corn earworm and sorghum webworm, and egg parasitism by Trichogramma spp. were recorded at 2–3 day intervals in three field tests. Sorghum webworm and corn earworm began oviposition as panicles emerged from the boot. Oviposition peaked 4–8 days later, near the time panicles began anthesis, but then declined quite rapidly. Oviposition by sorghum webworm ceased approximately 10–12 days after panicle emergence began. Corn earworm oviposition continued at low levels until sampling was terminated 14 - 17 days after panicles began emgergence. Rainfall appeared to mediate effects of panicle maturity on oviposition. Corresponding peaks in larval density were not observed for corn earworm or sorghum webworm, possibly because of heavy parasitism by Trichogramma spp. A paired comparison procedure was used to determine preference of small, medium, and large corn earworm larvae for panicles of different maturity. Early instars preferred newly flowered panicles and concentrated feeding on pollen filled anthers. Late instars preferred panicles in the soft-hard dough stages, while intermediate instars exhibited no significant preference. These data suggest that corn earworm oviposition is concentrated at anthesis because pollen enhances larval development and survival.

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