Location: Vegetable Crops Research2012 Annual Report
1a. Objectives (from AD-416):
Initiate an innovative and integrated research program to characterize current insect pest damage of cranberry crops, develop efficacious and economical insect Integrated Pest Management (IPM) strategies for cranberry production systems, and respond to emerging insect pests. Evaluate field performance under current commercial conditions as well as under enhanced production systems utilizing new cranberry varieties and new water management technologies. Develop baseline information on the arthropod communities associated with cranberries.
1b. Approach (from AD-416):
Three lines of inquiry will be initiated. First, a large-scale investigation of the biology and phenology of the major cranberry pests will be conducted, both in field and controlled-environment settings. There are three lepidopteran species (cranberry fruitworm, black-headed fireworm, and Sparganothis fruitworm) that are of particular concern to Wisconsin growers. Second, the arthropod communities associated with cultivated, wild, and feral cranberry populations will be collected and identified (cranberry populations will be assayed using next-generation genomic sequencing). This information will not only provide basic information on the diversity of arthropods associated with Wisconsin’s cranberry populations, but will also provide evidence of host-plant resistance. Such information will ultimately inform cranberry breeding trials. Third, the trophic structure of the arthropod communities will be mapped using a novel method of trophic level estimation (compound-specific stable isotope ratio analysis). This method is a powerful tool in food web ecology because the approach accounts for variability in the background concentration of 15N (a non-decaying, heavy isotope of nitrogen). A team of scientists, including a postdoctoral researcher, will oversee and conduct the trophic structure work.
3. Progress Report:
We continue to collect arthropods from wild and cultivated sites in central Wisconsin. To-date, we have extracted all plant, detritus, and arthropod biomass from field samples. Plant biomass has been identified, dried, and weighed. Samples have been prepared and submitted for isotopic ratio analyses, which will allow us to determine whether the background 15N signatures differ significantly among the sample-sites in central Wisconsin. We have also separated, curated, and identified all arthropod specimens. Thousands of arthropod specimens were found, largely represented by five ant species, a diversity of staphylinid beetles, and many arachnids. A moderate number of herbivore taxa were found, but notably, very few lepidopteran specimens. Most herbivores were sap-feeding hemipterans. A subset of the herbivores has been dried and will be submitted soon for isotopic analysis. Once these specimens have been analyzed, we will know which specimens can be targeted for subsequent compound-specific analysis. This research relates to initiating an innovative and integrated research program to characterize current insect pest damage of cranberry crops, develop efficacious and economical insect Integrated Pest Management (IPM) strategies for cranberry production systems, and respond to emerging insect pests and to develop baseline information on the arthropod communities associated with cranberries.