Every time I’ve experienced a borer I see a lot of damage to the stem but I’ve never experienced them and sunflowers. I will have to take a look at that article I guess either way is it best to just re-plant? It would be a little late but if I did it now I would have time I have one row of Mammoth and four rows of one called Moonwalker. It may be coincidence but I haven’t noticed this problem with the row of mammoth Just the Moonwalker. But it could because there’s more