Shedding light on Light Leaf Spot
Light Leaf Spot ( LLS ) is becoming an increasing issue for farmers across the UK . We ensure you ’ re not left in the dark .
Oilseed rape growers across the country will have to be on the lookout for Light Leaf Spot this year .
Ms Julie Smith of ADAS said , “ The prediction models and the research say that the risk is widespread and will be high again this year .” Light leaf spot ( LLS ) is no longer a disease confined to the northern areas of the UK , it is now very widespread , and commonly found down south .
According to Ms Smith this is due to a combination of factors , “ More oilseed rape is grown now than a decade ago and rotations have got a lot tighter , with rotations of one in three years not uncommon . LLS relies on inoculum from the previous year to initiate infection and the majority of crops are now established using minimum tillage techniques so infected stubble is not buried . We have had severe epidemics recently so there is plenty inoculum around .”
Early control of Light Leaf Spot
“ Get on top of LLS early ,” is the key message from BASF Business Development Manager , Clare Tucker , “ Hopefully an autumn fungicide has been applied , but it is still important to monitor the crops from late winter onwards . It is very difficult to see LLS in the early stages , so collect plants and incubate the leaves .”
This involves placing leaves in a poly bag for three to four days at room temperature to exacerbate any symptoms . Ms Tucker added , “ Little white spore masses appear on the leaf and it just gives you a heads up that your crop is infected . Aim to treat the crop as soon as you see the symptoms either from the incubation test or in the field , this may well be in late January or February .”
" Aim to treat the crop as soon as you see the symptoms either from the incubation test or in the field ."
Ms Smith said , “ All of the products are much more effective if applied in a protectant rather than a curative situation . If you apply your fungicides in a timely manner , you are still able to achieve good control .
We have found that you can get good control of LLS if the first application is as soon as the disease is spotted in the autumn / winter and then another in spring before stem extension ; 0.75 t / ha yield responses under severe epidemic pressure , from two applications if they are well timed . However , fields can be too wet to travel over winter and often LLS is not spotted early enough .”
Ms Tucker said , “ It is crucial that growers start to get on top of LLS before stem extension begins because after this LLS starts to cause yield loss .
" It is crucial that growers start to get on top of LLS before stem extension begins because after this , LLS starts to cause yield loss ."