Reduce the levels of the disease in a crop by using an integrated strategy involving varietal resistance, controlling the green bridge, drilling date and trash burial.
Target: pre-drilling, rotational strategies
Key aim: reduce the levels of the disease in a crop by using an integrated strategy involving varietal resistance, controlling the green bridge, drilling date and trash burial
Choosing to grow a wheat variety which has a better disease spectrum is the first and easiest tool you have to help manage disease in your crop. It is good agricultural practice to choose a variety which has inherent disease resistance, as it reduces your reliance on fungicides to control disease and may lead to greater overall output.
The HGCA Recommended List (RL) provides growers a 1-9 scale on varietal resistance including Septoria tritici, Septoria nodorum, yellow rust, brown rust, mildew, eyespot and fusarium ear blight. These are developed through a series of trials throughout the UK over a number of years. Bayer CropScience run a series of trials throughout the UK on the current RL list to quantify the benefits of disease ratings. At our Callow demonstration site you can clearly see the benefit of disease resistance in the untreated crops as you progress through the resistance ratings. What you can also see in this graph is that there are currently no varieties on this list which are fully resistant to Septoria tritici with the highest rating being seven.
The treated yields of more resistant varieties do not equal that of the more susceptible varieties but the untreated yield shows that yields will not fall in situations where disease control from fungicides is not effective.
- Controlling the green bridge:
Septoria tritici and yellow rust can both overwinter on volunteers and older leaves within the crop. Ensure that volunteers are sprayed off on overwintered stubbles to control the inoculum levels in following and nearby crops.
- Drilling date:
although planting crops earlier may increase the chance of maximising the yield it will significantly increase the risk of disease epidemics. If you are planning to drill early then consider offsetting the increased risk by choosing a variety with good resistance.
Septoria tritici is primarily a trash based disease so spores from previous crops get blown into new crop. If growing a crop adjacent to or after a previous wheat crop then consider burying the previous crop debris by ploughing.
Controlling disease as part of an integrated crop management approach, using both cultural and chemical control, will reduce the overall levels of disease infection and help maximise yields. The treated yields of more resistant varieties do not equal that of the more susceptible varieties but the untreated yield shows that yields will not fall in situations where disease control from fungicides is not effective.