Reduced risk management of lygus plant bugs in Ontario strawberry

Project Code: PRR06-880

Project Lead

P. G. Mason and A. B. Broadbent - Agriculture and Agri-Food Canada

Objective

To deliver farmer participatory training and investigate trap cropping, classical biological control and low risk pesticide applications for an integrated approach for the control plant bugs in strawberries

Summary of Results

Context

Tarnished Plant Bug (TPB), Lygus lineolaris, is a key pest of strawberries in Canada. TPB feeding causes deformed berries which are unmarketable, posing a serious threat to this crop. Current controls for TPB primarily involve pesticides. Biological control of TPB with parasitoids is a potential reduced risk solution.

A tiny parasitic wasp (2-3mm), Peristenus digoneutis has been released in the United States for control of TPB on alfalfa and has shown some success. The wasp lays eggs inside the body of immature TPBs. The eggs hatch and immature wasp larvae feed within the body of the TPB, killing it before it can complete its life cycle and thereby reducing the population. This parasitoid, when used in combination with trap cropping (planting other susceptible crops nearby to which TPB controls may be applied) has the potential to significantly lower TPB numbers.

Approach

A multidisciplinary team consisting of scientists from Agriculture and Agri-Food Canada (AAFC) and CABI Europe- Switzerland and extension specialists from the Ontario Ministry of Agriculture, Foods and Rural Affairs (OMAFRA) was formed to develop and coordinate a project which would examine the efficacy of the wasp and trap cropping, used in combination, while facilitating grower adoption. A grower participatory approach was taken, allowing growers to make the decisions about the management strategies used on their farms.

In 2007 and 2008, P. digoneutis was released at several locations in eastern and southern Ontario and trap crops were planted in strategic locations on farms after consultation with growers.

Through training sessions, on site visits and round table discussions, growers were encouraged to take part in defining management strategies, based on biological control, most appropriate for their operation. Individual reports for each operation were developed, with the data demonstrating the impact of grower decisions on TPB. Follow-up meetings with each grower provided a forum for answering questions and deciding on modifications that might be needed to improve the management of TPB. The mutual exchange of information between researchers and growers helped refine the protocol to address issues at specific operations.

Results

Collections indicate the wasp is now well established in eastern Ontario and parts of southern Ontario. Records also suggest the wasp had naturally dispersed from earlier introductions. Though the wasp introductions will take some time to effect a substantial decrease in TPB populations, preliminary results are promising.

Managing a pervasive pest like TPB is a challenge for growers. To effectively make use of integrated pest management (IPM) strategies to reduce the chemical burden, knowledge of the underlying scientific principles is essential. Grower participatory projects like this are valuable as they educate growers, while helping scientists understand the day to day realities of the working Ontario strawberry farm. By building capacity to deal with these pests, growers can make decisions about how their crop might be best managed using biological control. As growers understand the economic and environmental benefits, these reduced risk approaches can be implemented to the benefit of both the grower and the consumer. This participatory approach, endorsed by the growers, can be an effective means of future research and development of reduced risk solutions on the Canadian farm.

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