Genomics Based Technology for Identification, Tracking, Insecticide Resistance Surveillance, and Pest Management of Vine Mealybug in Vineyards

Goals / Objectives
Mealybug pests are one of the serious pests of winegrapes listed as a priority for research by the CDFA PD/GWSS board. The goal of this project is to develop resources aimed at identification, tracking, and control of vine mealybugs in California wine grape production. The following objectives will use genomic technologies to characterize vine mealybug populations in California regarding pest movement and insecticide resistance and develop control methods based on genomic targets. 1. Develop genomic resources for vine mealybug (genome sequence, profile endosymbionts). 2. Develop genetic markers to track mealybug populations in California. 3. Characterize microbial symbionts associated with field collected vine mealybug populations in relation to insecticide resistance information. 4. Development of antisense oligos (ASOS) targeting bacterial symbionts of vine mealybug for pest management.

Project Methods
To generate a high-quality reference genome assembly for vine mealybug, DNA will be extracted from colony-raised insects and sequenced using next generation sequencing platforms available at UC Davis. Once a reference genome has been created, insects from 10-15 populations collected from different regions of California will be sequenced that represent as much as possible the genetic variation in vine mealybug in California grape production. In addition to the vine mealybug genome, high throughput sequencing of these DNA samples will allow analysis of insect-associated microbial populations. Some of these microbes are symbiotic bacteria that mealybugs depend on for survival. These essential symbiotic organisms will be sequenced fully from vine mealybug using a combination of long-read (Oxford Nanopore Technologies) and short-read (Illumina) sequencing technologies and used as targets for gene silencing. Based on genome sequences from different vine mealybug populations, molecular markers will be developed for identification and tracking of vine mealybug in California. DNA sequence information from the different vine mealybug populations will be combined with insecticide resistance information obtained in a separate study to evaluate prevalence of insecticide resistance in vine mealybug in California. If insecticide resistance is identified in specific populations, genetic markers will be developed to track spread of resistance between different areas. DNA sequence information for the primary microbial symbiont species found in vine mealybug from California will be used to develop custom antisense oligo molecules which target the symbiont species that are essential for insect survival. These antisense oligos will be tested for ability to disrupt mealybug symbiont species and consequently reduce insect fitness and survival.