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The utilization of Oberea erythrocephala as an additional
bio-control agent on leafy spurge in the Little Missouri River basin

Denise Olson

Question 1: What major problem or issue is being resolved and how are you resolving it?

Leafy spurge root placement in the soil appears to limit the success of Aphthona spp. to only a particular range of environmental conditions, and leafy spurge inhabits a wide rang of different environmental habitats. The successful establishment of Oberea will support the efforts of managing leafy spurge with another bio-control agent in areas where Aphthona spp. have not been successful. Eight-hundred Oberea have been released at selected sites in the TEAM leafy spurge demonstration areas in the Little Missouri River basin to determine the suitability of this beetle as an additional bio-control agent where the success of Aphthona flea beetles had been less than satisfactory.

Question 2: How serious is the problem? Why does it matter?

Leafy spurge infest about 1.2 million acres in the four-state region of Montana, North Dakota, South Dakota and Wyoming. In many leafy spurge infested areas, where the success of Aphthona flea beetles is less than satisfactory, the terrain is not suitable for herbicide treatment or
cultural control methods. Thus, land managers and owners have limited tools for managing leafy spurge in these areas, and consequently they would incur an economic loss from reduced agricultural production on these lands.

Question 3: How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned?

The TEAM Leafy Spurge project is a part of the USDA/ARS Area-Wide Management Program. It is a component of Crop and Commodity Pest Biology, Control and Quarantine (304). TEAM Leafy Spurge complements efforts to develop new and improved pest control technologies and assess component technologies for integrated pest management (IPM) systems.

Question 4: What were the most significant accomplishments this past year?

Eight-hundred Oberea erythrocphala where released into each of four selected sites in the TEAM leafy spurge demonstration areas where the success of Aphthona flea beetles has been less than satisfactory. Based on the presence of oviposition, girdling and movement by Oberea observed during mid-august this past year, this cerambycid beetle has accepted the leafy spurge in the four release sites.

Question 5: Describe the major accomplishments over the life of the project, including their predicted or actual impact.

The duration of this project has been one year (1999). We successfully released 800 Oberea at each of four selected released sites in the TEAM Leafy Spurge demonstration areas in the Little Missouri River basin. We have also recorded that Oberea accepted the leafy spurge in each of these area, successfully using leafy spurge for reproduction. Observation taken during the spring of 2000 will provide us with information as to the actual impact of Oberea on the leafy spurge stands in each of the four release sites. I predict that Oberea will have a very low, but noticeable, impact on leafy spurge stands when observations are made during the spring of 2000. Oberea would appear to establish at a slow rate, gradually reducing the presence of leafy spurge over period of 3-4 years.

Question 6: What do you expect to accomplish, year by year, over the next 3 years?

We will release an additional 200 adult Oberea to supplement the 800 beetles released during1999 to obtain 1000 per site in the TEAM Leafy Spurge demonstration areas as proposed in the 1999 project. Additional beetles will be collected, as population size in established insectaries will allow, and be redistributed evenly among the release sits in the Little Missouri River basin during 2000. Data will collected on the impact of Oberea on leafy spurge stands at the release sites during next three years. Data also will be collected on Oberea oviposition and reproduction to determine level of establishment in each of the release sites during the next three years. At release sites where Oberea may appear to have a low establishment rate, additional beetles will be added to the site to help increase the level of establishment over the next three years.

Question 7: What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?

This project was initiated during the 1999 production year and sufficient data has not been obtained to date to transfer new technologies to industry, farmers, and other scientist. We will be reporting research data, collected over the next few years, to scientist and other technical groups at the Annual Leafy Spurge Symposium, Annual North Dakota Weed Association meetings and other pertinent scientific associations. We anticipate that this new technology would be available after three years of testing and data collection in the field. Like the Aphthona flea beetles, Oberea erythrocephala will not be successful under all environmental conditions inhabited by leaf spurge. Therefore, this new technology will not be adoptable in all leafy spurge habitats. Data collected on the biology and behavior of Oberea, at the four release sites in the TEAM leafy spurge demonstration areas will provide information as to the type of environment suitable for the success of this bio-control agent.

Question 8: List your most important publications in the popular press and presentations to non-scientific organizations and articles written about your work

None to date.

Question 9: Scientific Publications:
None to date.
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