Sowing wildflowers into potato crops could reduce aphid-carried viruses and offer an alternative to declining access to insecticides for growers, according to Scottish Agronomy. In Scotland, trials are being carried out to discover the effectiveness of growing flower strips in tramlines and headlands to promote natural predator populations to reduce pests as part of an Integrated Pest Management (IPM) strategy.
Eric Anderson, senior agronomist and potato specialist at Scottish Agronomy, is leading the trials with Scottish Agronomy potato member Jim Reid on Milton of Mathers Farm. Jim is the current AHDB Strategic Potato (SPoT) farm host and, with AHDB, Eric, and Colin Herron and Colin Ross from McCain Potatoes, is looking at different sustainable measures as part of the four-year SPoT farm project.
Jim, who grows 80 hectares of seed potatoes, said: “The trade for Scottish seed potatoes is reliant on an excellent reputation for virus health, and with the pressures of reduced access to insecticides, whether through regulation or greater resistance in aphids. It is more important than ever to look at how we can use biology and targeted chemistry to keep disease at a minimum.
“There is a lack of a holistic approach to IPM which integrates both the traditional and modern tools. Through these trials we are exploring the roles biology, ecology and evolution play and how we can rethink aphid and potyvirus control on a commercial scale.”
The virus incidence in 2019 seed potatoes crops hit a 20-year high and this season’s inspections give a similar impression for 2020. The main culprit is Potyvirus, PVY, principally the PVYN strain, but PLRV has also increased albeit from a very low base.
The effectiveness of the wildflower strips in boosting pest control strongly depends on their botanical composition. Often non-crop elements that are designed for bird or pollinator conservation do not simultaneously make resources available to biological control agents.
Research showed that of the three natural enemies, hoverflies increased the most in the strips compared to surrounding potatoes, while the populations of lacewings and ladybirds also rose significantly. Eric warns that there is a lag period until natural enemies have time to build numbers, therefore an IPM approach using both nature and chemicals such as mineral oils will be important.
Source: Scottish Agronomy. Read the full article here