UK: High Alternaria risk in potatoes demands urgent early intervention
Syngenta Field Technical Manager, Stephen Williams, warns the continuing warm and changeable weather has increased the risk of Alternaria (Early Blight) development. “Outbreaks of the disease have already been observed, from the west of England right across to Norfolk.
“The risk of attack increases where conditions are hot and dry, if the crop is under nutrient or drought stress, or where there is a history of Alternaria on the farm. In many instances all these risk could be conspiring together this season. Furthermore, a high proportion of current varieties have some level of susceptibility to the disease,” he advised.
Alternaria is best controlled with an Amphore Plus protectant programme, timed before the end of flowering. However, this season Mr Williams advocates growers may need to consider starting treatments earlier in high-risk situations.
“Amphore Plus can be applied three times per season, either as a block or alternating in the blight programme on a seven to 10 day interval, to see the crop safely through the high-risk conditions,” he said.
Mr Williams pointed out that in addition to proven Alternaria control, Amphore Plus also includes the highest level of blight protection, equivalent to a full-rate application of Revus. “With the large number of blight outbreaks already reported this season there is an inherently high potential of further spread, especially in irrigated crops.
“Reverting to seriously weaker blight fungicides that are perceived to have some effect on Alternaria, such as mancozeb, would expose crops to far greater risk of damaging disease infection,” he added. “The good news is that with Amphore Plus there is no need for growers to compromise on the all-important blight protection when looking to control Alternaria too.”
For more information:
Andrew Curtis
Syngenta
Tel: +44 (0)1223 883462
Email: andrew.curtis@syngenta.com