Assessing Nematode Diversity in Natural and Managed Blueberry Habitats

Assessing Nematode Diversity in Natural and Managed Blueberry Habitats

Summary

Highbush blueberry (Vaccinium corymbosum) is an economically and ecologically important plant species in southern New Jersey. V. corymbosum is cultivated throughout Atlantic and Burlington counties in southern New Jersey in 7,100 acres with production valued at $62.5 million (NASS, 2010). It also thrives naturally in the understory of the Pinelands National Reserve and is ubiquitous in similar woody areas adjacent to commercial blueberry fields. The oriental beetle (Coleoptera: Scarabaeidae: Anomala orientalis) is a key blueberry pest that feeds on blueberry bush roots, which weakens and sometimes, kills the plant. On conventional New Jersey commercial blueberry farms, this pest problem is managed solely through soil applications of imidacloprid due to the sensitivity of the pinelands ecosystem and high water table of the coastal plain. To reduce the dependence on this treatment, other options are needed. Biocontrol using entomopathogenic nematodes is a viable option for suppressing oriental beetle. To build the foundation for the development of an augmentative, or if applicable, conservation biocontrol program using EPNs, I will quantify endemic and established entomopathogenic nematode communities associated with wild and cultivated blueberry soil habitats.

Objectives/Performance Targets

The main objective of this project is to assess EPN nematode communities in wild and cultivated blueberry.

Last season, before acquiring this funding, we started the project described in the proposal. Five grower fields in Atlantic county New Jersey with bordering natural Vaccinun habitats were used for soil sample collections. Within each site, a 50×50 foot block was used to collect soil samples three times over the course of the blueberry season: early season (second week of May), mid-season at fruit set (second week of July), and post-harvest (second week of September). Within each block at each sampling time, ten different plants were randomly selected within the block and eight oakfield samples were taken from the radius of the plant’s root zone. In the lab, sub-samples (two 100g samples) of each sample will be baited with five waxworm larvae (Galleria mellonella). To identify EPN species, the collected progeny were used to produce new infections in wax worms. Sub-samples of each sample will also be sent to the Rutgers Plant Diagnostic Lab and Soils Lab to identify known plant parasitic nematodes and nutrient and texture differences between the soils of each habitat. All of the above in-lab processing has been completed for this first season.

EPN species can be identified to some extent based on waxworm cadaver coloration and the morphology of the infective juveniles and adults. All isolates will also be identified to species using standard molecular methods by a collaborator (Dr. S. Patricia Stock, University of Arizona). Dr. Stock will identify our samples over the course of the spring 2012 semester. We found four distinct cadaver colors and Dr. Stock will assist us in IDing these samples as well as any cryptic or new species in the samples. The diversity indicies can be calculated with information on number of species present and statistics used to produce the results from this first year of data before the new season.

Accomplishments/Milestones

Right now, the previous season’s data is being finalized for analysis and planning is underway for the coming season for which the SARE Graduate Student Grant funds will be used. We will be meeting with growers during March and April to confirm their involvement in the coming season. I will be presenting the results from the first season at blueberry grower meetings this summer.

Impacts and Contributions/Outcomes

The biggest impact my project has had thus far is in interacting with growers. By doing this study on site in grower’s fields, I am engaging growers and explaining my work in an informal setting. In many cases, this is an opportunity for growers to become more personally invested in the results of the study and may be more likely to support further on farm studies or eventually, use nematodes to manage belowground root feeders in blueberry. I will continue interacting with growers in the following season.

Collaborators: