Author
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Bruck, Denny |
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Submitted to: Journal of Environmental Horticulture
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/22/2005 Publication Date: 6/1/2006 Citation: Bruck, D.J. 2006. Effect of potting media components on the infectivity of Metarhizium anisopliae against the black vine weevil (Coleoptera: Curculionidae). Journal of Environmental Horticulture. 24(2):91-94. Interpretive Summary: The black vine weevil (BVW) is a serious pest of nursery crops, particularly in the Pacific Northwest. The insect killing-fungus, Metarhizium anisopliae (F52), has recently been registered by the US Environmental Protection Agency for BVW control. The objective of this study was to determine M. anisopliae persistence, measured as the ability of the fungus to kill BVW larvae, in five common soilless potting media components (coir, fir bark, hemlock bark, peat moss and perlite). Each media component was incorporated with ½ lb/yd3 of fungal granules at potting and fungal persistence determined for 133 days. Experiments were performed with and without plants to determine if the presence of a plant impacted fungal persistence. Overall, the fungus persisted well in all of the potting media components tested up to 133 days post application. Persistence was somewhat lower in the first run of the experiment, likely due to fluctuating media moisture. In the second run of the experiment with more stable media moisture levels, the percentage of larval infection did not drop below 88% in any media at 133 days post application. It is likely that M. anisopliae will persist well and provide high levels of BVW larval control in most of the commercial potting media used in containerized nursery production, particularly those comprised primarily of the media components tested in these studies. Technical Abstract: The black vine weevil (BVW), Otiorhynchus sulcatus (F.) is a serious pest of nursery crops, particularly in the Pacific Northwest. The fungus, Metarhizium anisopliae (F52), has recently been registered by the US Environmental Protection Agency for BVW control. The objective of this study was to determine M. anisopliae persistence, measured as pathogenicity against BVW larvae, in five common soilless potting media components (coir, fir bark, hemlock bark, peat moss and perlite). Each media component was incorporated with ½ lb/yd3 of fungal granules at potting and fungal persistence determined for 133 days. Experiments were performed with and without plants to determine if the presence of a plant impacted fungal persistence. Overall, the fungus persisted well in all of the potting media components tested up to 133 days post application. Persistence was somewhat lower in the first run of the experiment, likely due to fluctuating media moisture. In the second run of the experiment with more stable media moisture levels, the percentage of larval infection did not drop below 88% in any media at 133 days post application. It is likely that M. anisopliae will persist well and provide high levels of BVW larval control in most of the commercial potting media used in containerized nursery production, particularly those comprised primarily of the media components tested in these studies. |
