Journal of Nematology (2006) 38, 474-482

David I. Shapiro-Ilan, Ted E. Cottrell, Ian Brown, Wayne A. Gardner, Robert K. Hubbard and Bruce W. Wood (2006)
Effect of soil moisture and a surfactant on entomopathogenic nematode suppression of the pecan weevil, Curculio caryae
Journal of Nematology 38 (4), 474-482
Abstract: Our overall goal was to investigate several aspects of pecan weevil, Curculio caryae, suppression with entomopathogenic nematodes. Specifically, our objectives were to: 1) determine optimum moisture levels for larval suppression, 2) determine suppression of adult C. caryae under field conditions, and 3) measure the effects of a surfactant on nematode efficacy. In the laboratory, virulence of Heterorhabditis megidis (UK211) and Steinernema carpocapsae (All) were tested in a loamy sand at gravimetric water contents of negative 0.01, 0.06, 0.3, 1.0, and 15 bars. Curculio caryae larval survival decreased as moisture levels increased. The nematode effect was most pronounced at -0.06 bars. At -0.01 bars, larval survival was <5% regardless of nematode presence, thus indicating that intense irrigation alone might reduce C. caryae populations. Overall, our results indicated no effect of a surfactant (Kinetic) on C. caryae suppression with entomopathogenic nematodes. In a greenhouse test, C. caryae larval survival was lower in all nematode treatments compared with the control, yet survival was lower in S. carpocapsae (Italian) and S. riobrave (7-12) treatments than in S. carpocapsae (Agriotos), S. carpocapsae (Mexican), and S. riobrave (355) treatments (survival was reduced to approximately 20% in the S. riobrave [7-12] treatment). A mixture of S. riobrave strains resulted in intermediate larval survival. In field experiments conducted over two consecutive years, S. riobrave (7-12) applications resulted in no observable control, and, although S. carpocapsae (Italian) provided some suppression, treatment effects were generally only detectable one day after treatment. Nematode strains possessing both high levels of virulence and a greater ability to withstand environmental conditions in the field need to be developed and tested.
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Database assignments for author(s): David I. Shapiro-Ilan, Ted E. Cottrell, Ian M. Brown

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.
	Curculio caryae
Steinernema carpocapsae/Xenorhabdus nematophila (entomopathogen)	Curculio caryae
Steinernema riobrave/Xenorhabdus cabanillasii (entomopathogen)	Curculio caryae