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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT OF BIOLOGICALLY-BASED STRATEGIES FOR MANAGING INSECT PESTS OF HORTICULTURAL CROPS

Location: Horticultural Crops Research

Title: Evaluation of Application Technologies of Entomopathogenic Nematodes for Control of the Black Vine Weevil, Otiorhynchus Sulcatus

Authors
item Bruck, Denny
item SHAPIRO ILAN, DAVID
item Lewis, Edwin - UC DAVIS

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 14, 2005
Publication Date: November 1, 2005
Citation: Bruck, D.J., Shapiro Ilan, D.I., Lewis, E.E. 2005. Evaluation of application technologies of entomopathogenic nematodes for control of the black vine weevil, Otiorhynchus sulcatus. Journal of Economic Entomology. 98(6):1884-1889.

Interpretive Summary: These studies were conducted to determine the efficacy of three species of insect killing nematodes (Heterorhabditis marelatus, H. bacteriophora and Steinernema riobrave) applied in infected host insects or as liquid applications for black vine weevil larval control. Experiments were conducted in the greenhouse and outdoors. Application of three infected hosts or 40 infective juvenile nematodes (IJs)/cm2 were made to infested Impatiens wallerana 5-7 days after larval infestation. Efficacy was assessed at 14 days in the greenhouse and at 14 and 28 days after nematode application in outdoor trials. In the greenhouse, all treatments with the exception the S. riobrave (host and liquid applications) provided nearly 100% efficacies after 14 days. The S. riobrave applications, while significantly better than the control, only provided 40 - 70% control and were not included in the outdoor trials. Nematode efficacy was slowed in the outdoor trials particularly in the infectd host applications. In the initial outdoor trial (soil temperatures <12 ºC) there were no significant differences between any treatment and the control after 14 days, efficacy after 28 days was improved from the 14 day evaluation, but not to the level seen in the second trial. In the second outdoor trial, in which soil temperatures were higher (> 12º C), the liquid application of H. marelatus and H. bacteriophora provided nearly complete control after 14 days. The infected host applications also performed extremely well in the second outdoor trial after 28 days.

Technical Abstract: These studies were conducted to determine the efficacy of three species of entomopathogenic nematodes (Heterorhabditis marelatus, H. bacteriophora and Steinernema riobrave) applied in infected host cadavers or as aqueous applications for black vine weevil larval control. Experiments were conducted in the greenhouse and outdoors. Application of three infected host cadavers or 40 infective juvenile nematodes (IJs)/cm2 were made to infested Impatiens wallerana 5-7 days after larval infestation. Efficacy was assessed at 14 days in the greenhouse and at 14 and 28 days after nematode application in outdoor trials. In the greenhouse, all treatments with the exception the S. riobrave (cadaver and aqueous applications) provided nearly 100% efficacies after 14 days. The S. riobrave applications, while significantly better than the control, only provided 40 - 70% control and were not included in the outdoor trials. Nematode efficacy was slowed in the outdoor trials particularly in the cadaver applications. In the initial outdoor trial (soil temperatures <12 ºC) there were no significant differences between any nematode treatment and the control after 14 days, efficacy after 28 days was improved from the 14 day evaluation, but not to the level seen in the second trial. In the second outdoor trial, in which soil temperatures were higher (> 12 ºC), the aqueous applications of H. marelatus and H. bacteriophora provided nearly complete control after 14 days. The cadaver applications also performed extremely well in the second outdoor trial after 28 days. Even though the potential total number of IJs estimated per pot was higher in the cadaver applied treatments, cool soil temperatures apparently delayed or reduced IJ emergence from cadavers resulting in delayed control.

Last Modified: 9/10/2014