Sustainable management tools for the redheaded flea beetle in nurseries

Sustainable management tools for the redheaded flea beetle in nurseries

Summary

Redheaded flea beetle (Systena frontalis) has become a serious pest insect of woody and herbaceous ornamental plants over the last several years. Three growers, two student undergraduate research assistants and I focused on identifying when key life stages of the redheaded flea beetle were active and correlating these stages with growing degree day (GDD) data and plant phonological indicators (PPIs). Additional research projects used entomopathogenic nematodes as a biological control of soil-dwelling larvae and determined susceptible host plants in the nursery. Growing degree days (base 50 degrees F/10 degrees C) were determined for larval and adult activity and shared at three grower meetings, two meetings with colleagues and provided information for a webinar hosted by NC State University.

This webinar has received an additional 65 hits since the initial presentation as of 23 October 2012. A poster was also presented at one of the meetings with colleagues and a fact sheet is currently being written. The ‘hands-on’ grower workshop is being planned for the spring.

Objectives/Performance Targets

Growing degree days and Plant Phenological Indicators:

Daily temperatures were recorded throughout the growing season as proposed at the cooperator’s location. Additionally, we gained preliminary data from two other growers when they learned of the project. Plant phenological indicators were noted during the different life stages of the beetle when possible. Few woody ornamentals were in an easily distinguishable phenological stage when second generation larvae and adults were becoming active.

Outreach: Info included in presentations to growers and colleagues during the summer fall and winter. Also was included in a poster and is being compiled in a fact sheet.

Insect phenology:

Larval and adult flea beetle activity or emergence was noted throughout the year. Cages were not used for first generation emergence because very few plants were found with larval populations in the root balls in the early spring. The cooperator suspected the cause was due to many of the previous season’s plants that were damaged, where the eggs and thus this past spring’s larvae would have been, had been sold. Some potted plants were found with larvae and were observed for adult emergence by the cooperator.

Outreach: Info included in presentations to growers and colleagues during the summer fall and winter. Also was included in a poster and is being compiled in a fact sheet.

Entomopathogenic nematodes:

Entomopathogenic (epns) nematodes were trialed in a laboratory experiment prior to use in the field. Three species of epns were used in the lab trial and in two separate field trials (two different growers). The laboratory trial demonstrated potential for successful biological control. Data from field trials is being analyzed. Baiting to with wax worms to evaluate epn viability in the potting soil after the experiment found little nematode activity.

Outreach: Laboratory data was shared with others at the same time describe previously. Field data will be shared in the fact sheet, winter meetings and the grower workshop.

Accomplishments/Milestones

Accomplishments/Milestones

Time of Year
Activity
Participant

1 March 2012
Begin GDD accumulation Cooperator (thermometer recordings); B.A. Kunkel (compare with weather records)
GDD accumulation proceeded as planned

April 2012
Acquire EPNs for field test
B.A. Kunkel
EPNs acquired from supplier as planned

1 May 2012
Monitor for larvae
B.A. Kunkel and Cooperator
Monitoring for larvae progressed as planned throughout the summer. First generation was difficult to locate.
1 May – August 2012 Plant Phenological Indicators
B.A. Kunkel and Cooperator
Plant phenology was recorded as planned

May 2012

Treat with EPNs B.A. Kunkel, conduct trial with Cooperator
Cooperator provide plants and space for trial
Application of EPNs for field test was delayed until 2nd generation because we did not know when larvae were active in the spring. Field experiments were conducted as planned.

May 2012

Record Adult Emergence
Cooperator and B.A. Kunkel
Locating larvae from overwintering eggs was difficult because some of the previous year’s stock plants that had experienced damage had been sold. Areas with suitable susceptible weed species convenient for caging were difficult to locate and this work with continue this spring.

June – August 2012 Visits to track beetle population kluctuations
B.A. Kunkel
Repeated visits discovered there are probably at least two generations of S. frontalis in the mid-Atlantic and possibly three. Overlap of generations during the mid- to late-summer (e.g., August) made differentiating generations difficult. Cooperators needed to start increasing pesticide application frequency to protect plants for sale, so this was a challenge.

September 2012

Fact Sheet written
B.A. Kunkel
Fact sheet is still being compiled. A poster sharing much of this information was put together for a meeting in September. The poster includes some GDD50 information, PPI, and host plant information.

October 2012

Workshop
B.A. Kunkel
Workshop has been rescheduled to the spring to help growers locate populations early

The project progressed mostly as proposed with difficulty working with weeds on nurseries and finding the initial larval population in the spring. Entomopathogenic nematodes continue to demonstrate potential in the laboratory and so far appear to be less effective in the field. The experiment using wax worms to determine epn viability indicates few nematodes survived or were persistent in the soil-less mixture for the 10 d of the experiment. Since the epns did not appear to work as well as hoped we began some host plant feeding trials in late summer to see if the beetles preferred some plants over others. Preliminary trials indicate that the beetles do make choices. The video making has had difficulty and work on this, the final poster and the fact sheet will continue.

• ONE12-163 Kunkel poster

Impacts and Contributions/Outcomes

Results from this project provide growers with a timetable both with plant phenology and temperature related guidelines to better target pest management strategies against this pest.

Collaborators: