Bayer’s SpotCheck is a free resource which provides farmers and agronomists with a definitive analysis on the presence of light leaf spot, Phoma, powdery mildew and downy mildew.
Take part in SpotCheck here.
To support farmers in identifying light leaf spot we have created a definitive guide below. Remember, for a conclusive diagnosis of light leaf spot and other diseases’ prevalence in oilseed rape crops, you can utilise Bayer’s free SpotCheck initiative.
Light leaf spot can be found in the crop as early as October, and so it is vital to familiarise yourself with symptoms from the very start of the growing season.
As a polycyclic disease, light leaf spot continuously releases spores and can spread at an alarming rate, making early identification vital, but notoriously difficult.
Early symptoms appear as white sugar-like spores, forming in a circular pattern, on either the top or underside of the leaf. This early white ‘sporulation’ is almost microscopic, so a hand lens is useful to help inspect each leaf one-by-one.
Incubating leaves can also act as an early warning system, drawing out symptoms sometimes weeks before they appear in the field.
Generally, the optimum temperature range for light leaf spot is around 16°C, but the disease can still develop between 4 and 20°C. A period of rainfall will also cause infection to spread more readily.
Later in the season (spring/summer), the disease spreads to stems and lateral branches. Look for small brown/purple lesions, often accompanied by black speckling. As the stem extends, the lesions expand and can become several centimetres wide.
In extreme scenarios, stems have been reported to split vertically along the lesion and even break.
In wet weather, spore droplets can be found on flower buds. Again, rain fall during flowering will cause the infection to spread more readily.
Severe cases of light leaf spot can cause infection to spread to the pods, causing twisting, distortion, browning and ultimately seed shedding.
The SpotCheck initiative is back to support growers and agronomists in the identification of the notoriously difficult to identify light leaf spot (LLS), as well as other oilseed rape diseases.
We know that growing oilseed rape can be challenging so we have gathered together everything you need to know about oilseed rape here.
Nearly 300 people completed our OSR: Big Picture Quiz in autumn 2018. By cross-analysing the findings we’ve been able to pull out some of the differences between those growers averaging over 4.0t/ha compared with those averaging under 4.0t/ha.