Environmental Entomology (1992) 21, 1441-1447

Mary Purcell, Marshall W. Johnson, Lynn M. Lebeck and Arnold H. Hara (1992)
Biological control of Helicoverpa zea (Lepidoptera: Noctuidae) with Steinernema carpocapsae (Rhabditida: Steinernematidae) in corn used as a trap crop
Environmental Entomology 21 (6), 1441-1447
Abstract: The planting of corn borders as a trap crop for the melon fly, Bactrocera cucurbitae Coquillet, potentially could cause increased infestation rates of Helicoverpa zea (Boddie) in adjacent tomatoes. The potential of the entomopathogenic nematode Steinernema carpocapsae Weiser for control of H. zea in corn borders was explored in research conducted both in Oahu and Maui, HI. Field tests were conducted to determine the concentration response of H. zea to S. carpocapsae in Oahu. The most effective of the treatments tested were 4,000 and 40,000 nematodes per milliliter of water, causing 57.6 ± 5.4 and 74.5 ± 17.4% mortality, respectively, 6 d after treatment.
In corn border trials with tomatoes, treated corn had 15 times fewer living H. zea larvae and 97% less damage to corn ears than in untreated corn. There was a mean of 0.03 ± 0.02 living H. zea larva per ear in the treated corn throughout the 9-wk treatment period, versus 0.45 ± 0.06 larvae per ear in the untreated corn. The mean feeding damage to the corn ears was significantly greater in the untreated corn, at 3.8 ± 0.25 cm, than the treated ears, at 0.16 ± 0.02 cm. During the primary period of H. zea infestation (tomato harvests 1-4), the marketable yield of tomatoes with corn borders treated with S. carpocapsae was 18% higher than the untreated corn border treatments. However, the tomato plots with no corn borders had consistently higher yields than those with corn borders throughout the six harvests.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Arnold H. Hara, Marshall W. Johnson

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
environment - cropping system/rotation
Research topic(s) for beneficials or antagonists:
application technology

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Helicoverpa zea	Maize/corn (Zea mays)	U.S.A. (Hawaii)
	Helicoverpa zea	Tomato (Solanum lycopersicum)	U.S.A. (Hawaii)
Steinernema carpocapsae/Xenorhabdus nematophila (entomopathogen)	Helicoverpa zea	Maize/corn (Zea mays)	U.S.A. (Hawaii)