A new approval for Syngenta’s Nemathorin gives potato growers the chance to reduce the costly tuber damaging effects of spraing caused by the tobacco rattle virus. The new label recommendation for the reduction of spraing enables growers to opt for an overall incorporation, or a new in-furrow application.

Spraing damage seriously reduces the value of potato crops, with very low tolerances for many fresh and processed markets. Yields, tuber shape and quality of crops grown from spraing infected seed can also be severely affected.

Nemathorin has been shown to reduce the incidence of spraing - by killing or paralysing the virus transmitting nematodes and consequently preventing infection by preventing them from feeding on tubers. It also limits the effects of nematode feeding damage, which will reduce yields.

Syngenta potato technical manager, Jon Ogborn, highlights the persistent activity of Nemathorin gives good protection through the crucial tuber formation phase and adds the relatively low water solubility of Nemathorin further increases its effectiveness, particularly in a wet spring and irrigated crops. “Dry soils reduce the risk of spraing, since the nematodes need soil moisture to move and attack newly forming tubers. However growers on light loam and sandy soils, where the incidence of spraing is highest, will almost certainly be irrigating at this stage to encourage tuber numbers.”

Spraing effects are the key problem with soil pests on Nottinghamshire potato grower Peter Savill’s farm, with potato cyst nematode PCN also present in some fields. “We test soils regularly and apply nematicide where we see there is a risk of damage; the effects of spraing and PCN can seriously reduce yield and, most importantly, affect quality of skin finish and cause internal damage to tubers,” he added.

Since he also grows high-value carrot crops in the rotation, where nematicides are used routinely, Savill is conscious that using carbamate products too frequently could give rise to enhanced degradation that would compromise the efficacy of all carbamates for nematode control. Following the approval for Nemathorin use on spraing in potato crops this season, he now has the opportunity to use a nematicide with a different mode of action, and possibly protect the value of carbamates for use in the carrot crop.

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