By Clayton Plant Protection
Clayton Plant Protection offer a choice of new prothioconazole-based fungicides in high quality formulations for early season disease control, to ensure the best start for crops.
New for 2020, Clayton are marketing two new fungicide options developed and manufactured by Finchimica, these are:
EC formulation containing 125g prothioconazole and 125g tebuconazole
EC formulation containing 250g prothioconazole
Light leaf spot was historically only significant in the North but has now spread throughout the UK. Untreated it can lead to yield losses of 50%. Although symptoms do not usually appear until January, early action in the autumn is essential since fungicides work best as protectants. Triazoles are the only effective fungicide group against light leaf spot with prothioconazole and tebuconazole offering good protection.
Split applications work best with the first being applied in the autumn after GS 20 (usually late October to early December) and a follow up spray in the winter or early Spring. A minimum of 50% of the full label rate should be applied at each timing depending on the severity.
Phoma leaf spot / Stem canker is the most significant disease affecting OSR in England. Unchecked it can lead to yield losses in excess of 0.5tn/ha. Although identified in the autumn as circular lesions on the leaves it is stem cankers forming in the following spring that cause yield loss due to lodging or early maturing.
The threshold for treatment is when 10-20% of leaves are showing symptoms. Small, younger plants are more susceptible. A split treatment with a minimum 50% dose of an active triazole fungicide such as prothioconazole will give the best control.
Label recommendations guide for OSR
Rate: apply 1.0 l/ha in 100-400 L/ha water volume, with a maximum of 2 applications per crop (2 L/ha maximum dose).
Target diseases (Autumn): Light leaf spot (reduction), Phoma leaf spot/stem canker (control).
Use rate: apply 0.7 l/ha in 100-330 L/ha water volume, with a maximum number of 2 applications recommended.
Target diseases (Autumn): Light leaf spot (moderate control), Phoma leaf spot/stem canker (control).