4 June 1999

Gains in yield

look good with new strob

By Andrew Swallow

TRIFLOXYSTROBIN, the Novartis strobilurin, will take cereal yields higher than current strobilurin standards, says the company.

Branded as the next generation of strobilurins, a UK launch is expected for spring 2000. Disease control is both broader spectrum and more persistent, maintains European fungicides development manager, Steve West.

"It is absorbed on to the wax layer of the leaf, which gives us long-lasting disease control. That persistence is the really crucial part – trifloxystrobin has an advantage over other fungicides," he says.

In French wheat trials last year brown rust control was over 90%, even seven weeks after application. But no change in conventional spray timings is advised at this stage.

"We believe it is better on the flag leaf than on the ear, and see an early application as having a value, too."

Curative action is limited, so a partner product or co-formulation is essential. The mode of action is the same as other strobilurins, so FRAC guidelines should be followed, too.

Novartis describes trifloxystrobins activity as mesostemic rather than systemic. Applications to one side of a leaf pass through to protect the opposite side from infection, but not new growth.

The molecule is highly volatile, producing a vapour effect within the canopy that can pass some protection to unsprayed leaves. It is also rainfast in less time than other strobilurins, the firm claims.

UK trials using a two-spray strobilurin programme last harvest suggest it has an edge on both Amistar (azoxystrobin) and Landmark (kresoxim-methyl + expoxiconazole).

All straight strobilurins had a half-rate of epoxiconazole (Opus) added to eliminate the triazole factor. Three-quarter rate trifloxystrobin produced the highest yield at 11.8t/ha. At a 60% rate yield was still 11.75t/ha.

Amistar at equivalent rates of 0.75 litres/ha and 0.6 litres/ha yielded 11.75t/ha and 11.1t/ha. Landmark at full-rate weighed in at 11.2t/ha and only 10.8t/ha at half-rate.

"In the mid-range we have a very clear advantage," says Mr West.

Approval for three formulations has been applied for in the UK – a straight containing 125g/litre of trifloxystrobin with a recommended application rate of 2-litre/ha, and co-formulations with cyproconazole or propiconazole.

Winter wheat, winter barley and spring barley approvals have been applied for in the UK, but Irish growers will have an approval for use on oats, too.

Broad-spectrum preventative control, better than either current strobilurin, is demonstrated by Novartis glasshouse work (see table). "And we know from field trials we have very good activity on yellow rust, comparable to brown rust," says Mr West.

"It is quite clear trifloxystrobin is the next generation of strobilurin," he concludes

Disease spectrum

Wheat Tf Km Az

Mildew 4 4 2

Brown rust 3 2 4

Septoria nodorum 3 2 3

Septoria tritici 4 2 3

Eyespot 2 2 2

Fusarium 1 1 1

Barley

Mildew 4 4 2

Net Blotch 4 1 4

Rhynchosporium 3 4 2

Key: Tf – trifloxystrobin, Az – azoxystrobin, Km – kresoxim-methyl. Preventive activity in greenhouse tests: 4 excellent, 3 good, 2 moderate, 1 poor.

NOVARTIS STROB

&#8226 Active ingredient: Trifloxystrobin

&#8226 Approval applied for as straight, + propiconazole, or + cyproconazole formulations

&#8226 More persistent and broader spectrum than current strobs

&#8226 Same mode of action – FRAC guidelines apply

&#8226 Available spring 2000 in UK & Ireland.

NOVARTIS STROB

&#8226 Active ingredient: Trifloxystrobin

&#8226 Approval applied for as straight, + propiconazole, or + cyproconazole formulations

&#8226 More persistent and broader spectrum than current strobs

&#8226 Same mode of action – FRAC guidelines apply

&#8226 Available spring 2000 in the UK & Ireland.

Disease spectrum

Tf Km Az

Wheat

Mildew 4 4 2

Brown rust 3 2 4

Septoria nodorum 3 2 3

Septoria tritici 4 2 3

Eyespot 2 2 2

Fusarium 1 1 1

Barley

Mildew 4 4 2

Net Blotch 4 1 4

Rhynchosporium 3 4 2

Key: Tf – trifloxystrobin, Az – azoxystrobin, Km – kresoxim-methyl. Preventive activity in greenhouse tests: 4 excellent, 3 good, 2 moderate, 1 poor.