Farmer Focus: I won a battle with wireworm for once

We finished harvesting our potato crop in record time this year. Yields and quality were not wonderful, but we did have one very successful result.

An 8ha field in which I found a very active community of wireworm last June was harvested with little or no damage to the tubers. This is a first for me, and I did not think it was possible.

See also: Cambs grower quits sugar beet as no longer worth the gamble

About the author

Peadar Whyte

Peadar Whyte farms 1,600ha of arable land across County Dublin, Meath, Kildare and Louth in north-east Ireland, as part of a multi-generational family farm, Whyte Brothers. The farm was established by Peader’s grandfather, Peter Whyte, and later expanded in partnership with Peter’s seven sons – including Peadar’s father, Eddie – and seven of their sons (Peadar’s cousins). Peadar grows wheat, barley, oats, oilseed rape, beans, potatoes and a variety of forage and cover crops. The wider farm operation also finishes 500 beef cattle annually.

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I treated the crop twice with entomopathogenic nematodes. The principle is that they move through the soil profile and enter openings in a wireworm’s body, releasing bacteria which multiply and kill the host.

In turn, they reproduce inside the dead wireworm and move on to look for more victims.

This could be a more environmentally friendly option that is better for soil health compared with traditional methods using strong insecticides, which kill almost everything in the soil.

The difficulty seems to be getting consistent results. I believe I was quite fortunate with the timing and conditions when I discovered the problem. Other farmers have had less success using nematodes.

I discovered the problem in June during the only period of high rainfall in the growing season. After talking to an agronomist, we decided to try a treatment straight away.

The key factors to success were high soil moisture and waiting until late evening to apply the nematodes, as they suffer from photodegradation if applied on the surface in sunshine.

The wireworm was easy to find close to the soil surface with mild conditions and the crop was not yet at full canopy.

I had a good chance of getting the nematodes close to the wireworm. A high water rate was also important when applying the nematodes with the sprayer.

The financial benefit from this biological control was substantial even though the product was expensive. Speaking to others, it seems this is not a reliable control method but my first time worked well.

It is encouraging to win a battle with wireworm for once, although my preference is still to avoid planting fields which have had wireworm problems.