The fungicide session at the annual AICC conference is always popular and this year was no different. Delegates packed the hall to listen to Julie Smith from ADAS Rosemaund on this year's approach to oilseed rape diseases, Dr Fiona Burnett tackled barley whilst Tom McCabe ran through septoria control.

Light leaf spot is all set to take off this season and we may be underestimating the problem. Julie Smith told delegates that she thought the current threshold of 25% is too high and that they should be looking at a 15% level as a guide for control. The disease can be difficult to spot in crops and agronomists should be incubating leaves for up to 48 hours to detect infections, she said. Also the disease is polycyclic which means that once in the crop it will continue to re-infect the crop over a long period. She urged the audience to adopt an early control strategy if the disease is found now. Stem extension sprays will be too late to control these early infections.

Sclerotinia is a disease which will be favoured by climate change. Timing is critical for control and more than one application of a fungicide may be required. Persistence of fungicides for control of Sclerotinia is only two to three weeks so if the crop has a protracted period of flowering and conditions are right, two sprays may be needed. Keep water volumes up says Julie as it is imperative to get the fungicide down onto the lower layers of the canopy. Infections from lower layers of the crop tend to be more severe as lower leaves are larger and form a bigger trap during petal fall.

Barley

Dr Fiona Burnett warned delegates that this season was looking like being a repeat of last year. Barley builds yield early in its development and as such responses to T1 fungicides can be greater than you would see with wheat. SDHI fungicides give good yield responses and are still giving good control of net-blotch, Rhynchosprium and ramularia in particular. Strobs are still effective against Rhynchosporium and can be more cost effective when applied in conjunction with triazoles. But SDHIs have the lead when controlling ramularia and are definitely valuable as a late season fungicide.