Managing the pests of Ontario's strawberries

Overview

Results

The team

Related information

So what's the problem?

The tarnished plant bug, Lygus lineolaris, is one of the most important pests of strawberries in north-eastern North America and at present intensive use of insecticide is the only means for control. The high risk of Lygus populations developing resistance to insecticides, and concerns about the impact of insecticides on beneficial insects, pollinators and human health, require new control techniques for plant bugs with no or only limited use of conventional pesticides.

What is this project doing?

The objectives of the project are:

Implementation of a sustainable and cost-effective IPM approach for Lygus plant bugs in strawberry systems in southern Ontario, combining trap cropping, classical biological control and limited chemical control
Replacement of toxic broad spectrum pyrethroid insecticides (Cymbush, Ripcord, Decis) registered for Lygus in strawberries with biological alternatives
Prevention of Lygus developing tolerance/resistance to insecticides
Limitation of insecticide applications to border areas and not directly to fruit
Establishment of P. digoneutis in southern Ontario, which may also help to reduce yield losses in additional crops attacked by plant bugs

The field implementation of the IPM strategy in Ontario was started in 2007 and has continued in 2008. Together with participating farmers, augmentative field releases of European biological control agent Peristenus digoneutis were conducted at two sites in southwestern Ontario and one site in eastern Ontario. In total, 8,880 parasitoids were released directly into trap crops adjacent to strawberry fields. Monitoring for pest density, parasitism, and fruit damage was then conducted throughout the field season to assess the impact of the IPM strategy.

Results so far

After consecutive releases of P. digoneutis in strawberry growing areas of Ontario, the analysis of plant bug samples collected at various strawberry growing sites in 2007 and 2008 showed that that the parasitoid is now well established in eastern and partially in southern Ontario. Records show that P. digoneutis was present at strawberry sites other than where it was released, which suggests that P. digoneutis dispearsed and continues to spread naturally throughout parts of Ontario. It is however too early to state whether the biological control agent has reduced Lygus populations in Ontario yet, but it is hoped that a continuous growth of P. digoneutis populations will have a similar long-term effect in Ontario as it was observed in the eastern USA.

The field implementation of the IPM strategy in Ontario was started in 2007 and has continued in 2008. Together with participating farmers, augmentative field releases of European biological control agent Peristenus digoneutis were conducted at two sites in southwestern Ontario and one site in eastern Ontario. In total, 8,880 parasitoids were released directly into trap crops adjacent to strawberry fields. Monitoring for pest density, parasitism, and fruit damage was then conducted throughout the field season to assess the impact of the IPM strategy.

Project Manager