Invest more in fungicides, reap higher profits. It is an easy message for manufacturers and distributors to suggest. But it’s equally easy to think “they would say that, wouldn’t they?”.
But dig a little deeper and the argument appears to stack up. Plenty of trials data suggest higher inputs mean higher yields. And when you consider that an extra £10/ha invested in fungicides only needs to add 0.08t/ha to pay for itself at a wheat price of £120/t, it doesn’t sound a bad idea.
Bayer CropScience trials last year compared what it termed a basic programme costing £46/ha and a premium one at £77/ha [insert box close to this text] across 12 varieties at four locations. That extra £31/ha always paid for itself, the firm’s Tim Nicholson says. Responses ranged from £9/ha to over £200/ha, depending on variety, based on a wheat value of £120/t.
Basic Programme Premium programme T1: Proline (0.4 litres/ha) + Bravo (1.0 litres/ha) T1: Proline (0.6 litres/ha + Bravo (1.0 litres/ha) T2: Prosaro (0.6 litres/ha) T2: Firefly (1.5 litres/ha) T3: Folicur (0.5 litres/ha) T3: Fandango (0.75 litres/ha)
But deciding how much more fungicide to use and, as importantly, where and when, is not straightforward, says Masstock’s Clare Bend (pictured). “It is not as simple as saying ‘spend an extra tenner’ it really depends on where you are starting from. If growers have underinvested in the past, they will need to invest more to move up.”The average yield response to fungicides is about 3t/ha, she says, based on five years of Masstock variety trials. Break that response down into component parts and each can be manipulated to make a more robust, reliable programme.
The base programme is a triazole at T1 and T2 – typically half-rate Opus followed by a three-quarter dose, she says. This costs about £40/ha, but only delivers half the average fungicide response, about 1.5t/ha.
T0s are fundamental this season, Ms Bend says. “The average response is 0.25-0.5t/ha. A straight chlorothalonil will give you the lower end of that response, whereas upgrading by £5/ha and adding in a fast-moving triazole should deliver another 0.25t/ha.”
At £120/t that is worth an extra £30/ha, she says. “It also buys you flexibility to time the T1 correctly, rather than panicking, zooming in too early and risking a big interval to the flag-leaf spray. It allows you to manage disease better, rather than the disease managing you.”
Use a T0
- Approximate cost: £10-12/ha*
- Reliability of response: 4/5 where septoria and rusts a threat
The obvious first addition to the base azole at T1 is to add chlorothalonil for septoria protection. That will produce a further 0.25t/ha on average.
Another upgrade worth considering is moving to a T1 with eyespot activity, such as prothioconazole or Tracker/Deuce. That could add a further 0.15-0.3t/ha in yield over Opus + chlorothalonil, she suggests.
As well as eyespot activity, prothioconazole helps suppress fusarium and has the advantage for septoria protection, but may need support on brown rust. “In rust situations we’ve found Helix – a co-formulation with spiroxamine – gives about 0.2-0.3t/ha more than Proline.”
It’s at least as good as Tracker at T1, she says, particularly if mixed with an adjuvant. “In trials adding an adjuvant to certain triazoles, including prothioconazole, has added about 0.35t/ha. It seems to help get the triazole into the leaf, as well as aiding spreading and wetting.”
Add chlorothalonil to base azole
- Approximate cost: £5-8/ha*
- Reliability: 3/5 – 5/5 depending on partner products
Switch to eyespot-active triazole
- Approximate extra cost: £2-6/ha*
- Reliability: 5/5 (drillings up to mid-Oct) 3/5 (later drillings)
FLAG LEAF SPRAYS
The best place for boscalid in the programme is in the flag leaf spray, Ms Bend believes.
“Deuce gave an extra 0.25t/ha over an Opus plus chlorothalonil flag-leaf spray.
“It is better on rusts than Opus, although not as good as strobilurins.”
On average, strobilurins have given an extra 0.35t/ha yield, but last season that response doubled to 0.7t/ha thanks to their rust control. “On some varieties it was well over 1t/ha.”
Putting both together, with epoxiconazole, would cover all the bases for varieties with a rust and septoria problem. Adding both boscalid and strobilurin, such as pyraclostrobin, makes most sense where there is high yield potential, she notes.
Add boscalid to base azole
- Approximate extra cost: £5-8/ha
- Reliability: 4/5 where septoria is issue
Add strobilurin to base azole
- Approximate extra cost: £10-12/ha
- Reliability: 5/5 where rust is an issue 3/5 if septoria
Typically, ear sprays will add 0.25-0.75t/ha. “The most reliable responses come from the more robust products.”
Growers need also to consider quality, Ms Bend says.
“Mycotoxins were a big issue last season, so it would be wise to use the best product to help reduce fusarium – and that’s prothioconazole.”
Use a robust T3 (prothioconazole-based)
- Approximate cost: £20/ha*
- Reliability: 5/5 if wet at flowering or late season foliar disease 2/5 if dry and low disease