Last May, I had to dig deep for an answer to the cause of a farmer’s poor wheat stand. Tom, who farms 5,500 acres of canola, barley and wheat south of Carseland, Alta., called me after he found some bare patches and missing rows of wheat in his field. “It may have been a plugged run in my drill,” he told me. But I wasn’t so sure, and I felt it needed to be investigated.
Tom’s 300-acre wheat field looked healthy enough, with a good stand and no signs of disease, but the east side had bare patches with few or no plants, and some whole rows were missing.
I found no evidence of any problems related to Tom’s seeding equipment or the drill speed at the time of seed application. There was nothing out of the ordinary with his fertilizer rates or seed treatments, and his depth settings and seeding rate were correct, his machinery was in good working order as well.
Tom and I also eliminated seed lot quality, herbicide carryover and environmental conditions as possible causes of the damage. Seed germination was fine because the rest of his stand was healthy and coming in well. He’d also taken the measure of buying certified seed with an excellent germination and vigour analysis. When I checked the seed rows in one of the thinner areas, I found the seeds had germinated and were forming roots.
Herbicide carryover was not the problem either. Tom hadn’t used any herbicides that would leave a harmful chemical residue in the soil for a long period of time.
The temperature had been cooler than average that spring, but in general, nothing out of the ordinary had happened concerning the weather. No frost had been reported after crop emergence, so it looked like environmental conditions were not to blame for the missing rows of wheat.
Something must be eating Tom’s crop, I thought. There were no signs of a gopher population in the area, but it could be insects.
Because wireworms had been reported in the surrounding area the previous spring, Tom and I had set traps earlier in the season, but we found nothing. Tom felt sure we weren’t dealing with wireworms, but I thought it was worth investigating. We’d had a cooler than average spring, so it was possible the wireworms were late, and that was why we didn’t find any in our traps earlier that season.
I went back to the seed rows where the plants were completely missing and after some searching I found seeds that had germinated and formed roots but were broken off at the soil surface. I dug a little deeper and found what I was looking for — wireworms!
These inch-long, segmented, yellowish to coppery worms are becoming a big problem. Bait balls aren’t always foolproof.
Once a producer knows he has wireworms in his soil, the implementation of management tools that will reduce the effect these pests have on the crop’s development is essential. Good seed bed preparation, careful consideration of all aspects of seeding, such as date, rate and depth as well as proper seed treatment will give your crop its best chance of getting well established.
Now that Tom knows he has wireworms present in his soil, implementing a good management plan will ensure healthy crops in the future. We couldn’t do anything to stop the wireworms that season, but most of Tom’s crop still filled out. At harvest time he found he’d only suffered a 20–25 per cent reduction in his yield.