1a.Objectives (from AD-416):
We will evaluate the performance of selective insecticides against vine mealybug and determine compatibility with natural enemies. We will measure the relative toxicities of the new generation of reduced-risk insecticides and establish a baseline as part of a resistance management program.
1b.Approach (from AD-416):
We will evaluate the impact of various reduced-risk insecticides on vine mealybug infestations and on its natural enemies. Both field and laboratory work will be involved to determine insecticide efficacies and management potential of various treatment regimens. Documents Reimbursable with UC Riverside (CDFA). Log 39849.Formerly 5347-22620-020-02R(11/10).
This is the final report for project 5347-22620-021-02R. This Reimbursable Agreement is in support of Objective 5– Refine insecticide-based management strategies; characterize factors influencing resistance to chemical insecticides and insecticidal proteins in transgenic crops; evaluate insecticide selectivity; support post-eradication pink bollworm resistance monitoring in Bt cotton, of the approved in-house project. Infestations of the vine mealybug, Planococcus ficus, have spread throughout table, raisin and wine grape growing regions of California, representing one of the biggest challenges to grape production in the state. The vine mealybug is cryptic, spending much of its time feeding beneath the heavy bark of grapevines. This feeding habit increases the difficulty of control efforts using conventional spray insecticides. If available selective insecticides can penetrate bark through volatilization, or are transported systemically within grapevines, they may offer chemical control options against vine mealybug that are less disruptive to beneficial insects than conventional insecticides. The efficacy of selected reduced-risk insecticides against vine mealybug was examined in five field trials in table grapes in Kern County, CA. A commercially-available formulation of spirotetramat proved most effective at reducing vine mealybug infestations below economic levels, requiring only a single treatment. Other evaluated materials provided lower levels of control even when used as components of a season-long regimen with other insecticides. Two of the materials evaluated (imidacloprid and thiamethoxam) were in the neonicotinoid class, which are widely-used systemic insecticides. Their concentration in grapevine tissues was monitored throughout the season. Recovery of these materials was highly variable among trials, possibly because of different soil types at each study site. These results will be used by producers and consultants to select and implement effective controls for this important pest of grapes.