Controlling rusts in winter wheat
Posted 10 years ago
09/03/2016
Bayer Recommends at T0 for Septoria and Yellow Rust:
- CTL 500 g/ha + tebuconazole or rust active strob
- Avoid use of primary azoles i.e PTZ/EPX at T0, it could compromise Septoria efficacy at the later timings.
- Do not apply > 4 weeks prior to T1.
- Anything applied prior to T0 as a result of high pressure (eg. yellow rust) should be treated as a distinct application.
- In rust resistant varieties, CTL at 500 g/ha may be sufficient for Septoria suppression.
The problem
Given the right conditions rusts can become a serious threat to your crop. With newer rust races cycling quicker in the crop, it is important to keep on top of rusts from an early stage. Luckily, rusts are relatively easy to control and if the threat is recognised early can be controlled in the programme.
What to do
With the mild autumn and winter we have had, rust can be found in the bottom of crops. For those thinking of applying a pre T0, this is only economic if rust has established on the newly emerged leaf. Once spraying has started, you need to keep the spray gap to below 4 weeks. At this time the focus would only be rust control so a multisite does not need to be added. Check all product labels for earliest application dates.
T0 is the critical time to get on top on any rust which is in the crop coming out of winter. Not only is the T0 important for rust control but it is also the key time to start your programme for Septoria. T0 sprays with fast moving azoles such as tebuconazole or cyproconazole and/or rust active strobs are essential. This should be mixed with 500 g/ha of CTL as standard to protect final leaf 4 infection from Septoria.
A crop managed for Septoria at T1 and T2 will ensure yellow rust control. It is important to keep spray gaps < 4 weeks between T1 and T2 for any product. If you do have established yellow rust in your crop at T1 or T2 add in a rust active strob.
The key to rust control is to get on top of the disease early in the programme