Search
  • Philip

Asymptomatic

It was reported from a national survey that ran October 2020 to March 2021, in partnership with ADAS and the Association of Independent Crop Consultants that the majority of crop-growing counties across the UK recorded positive results for light leaf spot infection. By the end of March 2021 when the initiative closed, 644 samples had been assessed by ADAS.


The percentage of samples showing infection after incubation was 76% in December, 68% in January, and 92% in February.


In March, ADAS assessed 163 samples, with 97% showing positive signs of light leaf spot, despite the colder winter weather and many of these crops having received an autumn fungicide application.


Plant genetics are one of the best ways to reduce risk of yield robbing infections but varieties with a resistance score of seven or higher are few. (There are 7 out of 29 on the 21/22 AHDB list, of which 3 I would recommend as suitable for commercial farming.)


Drilling date: Early drilling to mitigate adult cabbage stem flea beetle grazing on emerging crops was a common practise in summer and autumn 2021. But early drilling will certainly lead to an increase in Light Leaf Spot infection RISK.


What next? Well, you could closely monitor for disease, perhaps send in samples to ADAS, to establish what is happening in your crop.


However, when it comes to protecting a crop against damaging infections it is worth remembering that fungicides like the triazoles have their “5 Star” ratings for protectant activity. If you require curative activity, even the best ones don’t cut the mustard!