|Reding, Michael - Mike|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2009
Publication Date: 6/2/2009
Publication URL: hdl.handle.net/10113/29777
Citation: Reding, M.E., Persad, A. 2009. Systemic Insecticides for Control of Black Vine Weevil, (Coleoptera: Curculionidae), in Container- and Field-Grown Nursery Crops. Journal of Economic Entomology. 102:927-933. Interpretive Summary: The black vine weevil is a serious pest of ornamental nursery crops where it feeds on a wide variety of species. The larval stage causes the most damage because it feeds on the roots and often kills its hosts. Management is based primarily on control with insecticides. Growers target either the larval or adult stage with their treatments. Targeting adults requires several sprays each season and targeting larvae has been effective only in container production. There are very few effective materials available and this insect has a history of developing resistance to insecticides. We tested several new insecticides where we targeted larvae in container- and field-grown plants. In addition, these insecticides were systemic so we evaluated their influence on adult feeding. We found that single treatments of clothianidin, dinotefuran, or chlorantraniliprole provided season-long control of the larval stage in container-grown plants. We also found that clothianidin and dinotefuran reduced feeding by the adult stage. In field-grown Taxus surface drenches of clothianidin or imidacloprid reduced numbers of larvae for an entire season. These tested materials should provide growers with effective alternatives to the current standards, which should help reduce the potential for resistance to those standards. Furthermore, our data suggests that a single treatment of clothianidin or dinotefuran will reduce feeding by the adult stage, which may lead to starvation or at the very least reduced egg production.
Technical Abstract: Black vine weevils (BVW) are serious pests of container- and field-grown nursery crops. Management programs usually target the larval stage in container-grown plants and the adults in field-grown plants. The number of effective control materials is limited and development of additional control options would be beneficial to growers. We tested several new insecticides for efficacy against BVW in container-grown Sedum and field-grown Taxus. In 2006 and 2007, clothianidin, dinotefuran, and chlorantraniliprole were applied as surface drenches to containerized Sedum and suppression of larval numbers and adult feeding were evaluated. In addition, bioassays were used to further examine the influence of systemic insecticides on adult feeding. In 2006, pots were infested with adult BVW 1 day after treating, and in 2007 pots were infested 1 or 43 days after treating. All three materials significantly reduced the numbers of larvae in 2006, but not in 2007 due to low numbers of larvae in the control plants. Dinotefuran and clothianidin reduced feeding by adult BVW on whole plants resulting in more blossoms, fewer damaged leaves, and a lower percentage of leaves damaged compared to untreated plants. In bioassays with detached leaves, all three insecticides reduced feeding compared to untreated plants. Efficacy and timing of clothianidin, imidacloprid and acephate surface drenches and imidacloprid and acephate soil injections were evaluated for BVW management over a one year period in field-grown Taxus. All insecticide treatments significantly reduced the numbers of larvae in field-grown Taxus compared to untreated plants; and all but the spring acephate drench improved the appearance of the Taxus (foliar rating) compared to untreated plants. All of the tested insecticides showed potential for preventing infestations of BVW larvae and reducing feeding by the adults in ornamental plants.