Japanese beetle (JB) (Coleoptera: Scarabaeidae) is an invasive generalist insect, feeding on over 300 plant species. JB are pests in a variety of field and fruit crops including corn, soybean, and grapes. Grape is a highly suitable host for adult JB, and turfgrass, a highly suitable oviposition site for JB, is commonly used in vineyards as groundcover between grape rows. JB adults found in a vineyard may have overwintered there as larvae or may have migrated in from surrounding landscapes. In this project, we will study how the composition of surrounding landscapes affects JB migration and infestation levels within vineyards over time. We have assessed landscape composition of the surrounding landscapes of Wisconsin vineyards using classifications derived from the NASS USDA 2016 Cropland Data Layer, and have classified vineyards with surrounding landscapes that are either high or low cropland. We plan to collect weekly samples of adult JB, and perform a weekly assessment of leaf damage at 10 high cropland and 10 low cropland vineyards during a 13-week period from mid-June to early September. Adult and larva of JB will be subsampled, and nitrogen isotopic analysis will be used to determine their origin as either migrant or resident to the respective vineyards that they were collected at. The outcomes of this project will include growers having a better understanding of how surrounding landscape impacts phenology, abundance and migration of JB within vineyards. The outcomes of this project will be relevant to growers as knowledge of JB population dynamics and landscape risk assessments are essential in developing effective management plans.
Project objectives from proposal:
The learning outcomes of this project are as followed: (1) Growers will have increased knowledge on how surrounding landscape influences JB migration into vineyards, (2) Growers will have increased knowledge on the phenology of JB and their spatial distribution within vineyards, and how these are affected by surrounding landscape (3) Growers will have increased knowledge concerning JB larvae overwintering in vineyards.
The action outcome of this project is as followed: Growers will make decisions on ground cover used between rows of grape plants, informed by our research on JB population dynamics.