Wireworm damage is increasingly impacting potato crops across the UK, extending to eastern counties and up into the Scottish borders.

Historically linked with grassland rotations in southern and western regions, recent shifts in farming practices and climatic conditions have facilitated the spread of this soil-borne pest, according to Andy Cunningham, Syngenta Potato Technical Manager.

Wireworms, in their larval stage, bore into tubers, leading to crop downgrade and creating entry points for rot and disease pathogens. The presence of adult click beetle species in an area indicates the potential threat of wireworm infestation.

At Syngenta Potato Power meetings, Cunningham identified several factors contributing to higher wireworm populations: increased green cover in rotations, enhanced organic matter and soil moisture retention, reduced soil cultivations in min-till cereal establishment, and decreased use of insecticidal seed treatments in arable crops. Additionally, maize serves as a favored host for wireworms.

Risk factors for wireworm damage, although beneficial for arable rotation, pose challenges for Integrated Pest Management (IPM) strategies. Cunningham emphasizes the importance of routine risk assessments for click beetle and wireworm populations before potato cropping.

Monitoring techniques include pheromone traps, targeting the three primary Agrostis (click beetle) species, and bait traps using seed balls with a 50:50 wheat and maize mix. These methods help gauge click beetle presence and assess potential wireworm threats.

With the loss of Vydate and Mocap, Nemathorin remains the sole nematicide available to mitigate wireworm damage. Cunningham notes, "Trials have shown results can be very good, and equal to the nematicides previously used for the purpose." However, application techniques are crucial, requiring precise incorporation into the topsoil layer.

Syngenta's trials with a new research product based on tefluthrin show promising results, offering improved vapor activity in the soil profile. This product is under review for UK registration for wireworm control in potatoes and maize.

Source - https://www.freshplaza.com