Fungicide programmes for oats, triticale and rye

Focused on the main spray timings, use this information to design fungicide programmes to optimise control and manage fungicide resistance risks in oats, triticale and rye.

Oats

Crown rust and mildew are the target foliar diseases in oats. Other diseases are either infrequent or not hugely damaging. Virus diseases, such as BYDV and OMV, can result in yield losses. Varietal disease resistance of oats to crown rust and mildew is published in the AHDB Recommended Lists.

Winter oats

T0: GS25–29

This timing is required for mildew control, where this disease is a risk.

T1: GS30–31

This is the most important time for disease control in oats. T1 usually consists of an azole for mildew control and a strobilurin for crown rust. If mildew is highly active at T1, it will not be controlled by azoles alone.

T2: GS39–55

A T2 is usually required for late-season foliar disease control. Later applications can also give control of fusarium head blight. If crown rust infection is seen, then consider an azole or, in high-pressure situations, an azole with strobilurin. For resistance management, do not use strobilurins alone for mildew control.

Spring oats

The spray programme for spring oats is the same as for winter oats, except a T0 is only required for mildew control in susceptible varieties in high-pressure situations.

Triticale

Yellow rust is the main disease of triticale, but septoria tritici, mildew, rhynchosporium, brown rust and fusarium are also important. Although triticale does not suffer as much as wheat from take-all, it is not considered a take-all break crop.

To protect against yellow rust, a three-spray programme is usually required: T0, T1 (GS32) and T2 (GS39). Use rust active azoles, with or without strobilurins, at T1/T2. Even in severe yellow rust situations, a spray before GS30 is unlikely to be economic. Septoria tritici levels are not usually as high as in wheat and SDHIs are not usually needed for disease control. Consider mildew and include protectants for mildew, as necessary.

Although there are differences in disease resistance between triticale varieties, these are not published in the Recommended List.

Rye

The main diseases of rye are brown rust, mildew and ergot. However, rhynchosporium, fusarium, eyespot, take-all, and septoria nodorum are also important. The strains of brown rust and mildew that infect rye are not the same ones that cross-infect with wheat or barley. Mildew can cause high yield losses (up to 25%), but is relatively easy to control. Rye undergoes rapid stem elongation and is tall, meaning it can grow away from rhynchosporium infection on the lower leaves, so this is less likely to spread up the canopy than in barley. Ergot tolerance is much higher in hybrid rye than in conventional rye. Rye does not suffer badly from septoria tritici.

To protect against brown rust and mildew, a three-spray programme may be required: T1 (GS29–30), T2 (GS39–47) and T3 (GS51–59). Use a combination of azoles, strobilurins and SDHIs. The T2 timing is the most important: protecting against brown rust late in the season ensures yield and quality is maximised. On biomass crops, the T3 timing is too close to forage harvesting to be economic.