Answering disease management questions is a focus for Bayer

August 2017

Every year Bayer receives questions around the use of arable fungicides. Not questions specifically about Bayer fungicides such as, “What dose rate should I use?”, but questions around best use practice.

Sometimes it is possible to answer some of these from the normal fungicide trials Bayer conducts in New Zealand. But it isn’t ideal as these trials are designed to generate data to support the registration of new products. It needs a special type of trial. Therefore, in spring 2015 Bayer invested significant resource into a five year programme of trials designed specifically to explore aspects around best use practice for its fungicide portfolio.

These replicated trials are conducted on both islands and cover both wheat and barley. They are a valuable resource for the training of Bayer’s own sales team as well as for merchant agronomists. Bayer makes the results available to farmers via merchant agronomists, Bayer Territory Managers, the Bayer website and in communications directly sent out by Bayer.

After two seasons what does the data show?

There couldn’t have two more contrasting seasons for conducting wheat fungicide trials.

Spring 2015 was characterised by crops with very low levels of disease. In fact disease levels were so low it was often hard to find enough disease to assess.

Spring 2016 was very different. On the lower North Island the pressure from Septoria leaf blotch (SLB) was so intense the untreated plots in the trial were dead before Christmas. On the South Island crops started clean but then disease developed aggressively through December and early January.

As you would expect in a series of trials covering such different situations the yield response showed considerable variation but the key finding was that a robust fungicide programme, based on a traditional three spray programme, was always profitable. The yield increase recorded was never less than 2 t/ha (2015 season) and in some cases it was 6 t/ha (2016 season).

The barley trials showed less variation over the two seasons.

Challenging levels of both scald and Ramularia leaf spot (RLS) developed with RLS being particularly difficult to control in 2016. In one trial leaf rust also developed aggressively.

The key finding was that applying a three fungicide programme, starting at GS30 and following up with a GS32 and GS39 application was very profitable.

The importance of the GS30 application was demonstrated very clearly in these trials. Not surprising as the lower leaves and stem of barley are very important for yield production.

In terms of additional RLS control a GS55 application of Aviator Xpro did provide additional control but in terms of profitable the increase was marginal.

What will 2018 trials show?

At this stage it is too early to know but what is clear is that these trials will yield another set of interesting results that will allow Bayer Territory Managers and Bayer merchant agronomists to provide the best possible advice for you.