Key Points
- In 2006, unlike the 2004 & 2005 seasons, yield response to fungicides in the more susceptible variety Savannah was similar in both dryland and irrigated crops (1.35 -1.74 t/ha irrigated and 1.49 - 2.01 t/ha dryland).
- In a trial with low levels of stripe rust (Puccinia striiformis) and a later leaf rust (Puccinia recondita) infection, there was no significant difference in yield between fungicide programmes tested.
- With a dry September and then a very cool summer, there was no advantage to applying strobilurin fungicide at either GS32 or GS39 in either dryland or irrigated crops.
- The most cost effective programme under both dryland and irrigated scenarios was Opus 0.5 l/ha applied at GS32 and GS39 followed by 0.25 l/ha of Amistar mixed with Opus.
- In south Canterbury, dryland Consort gave a maximum 1.86 t/ha yield response to fungicide as a result of a low level leaf rust infection and a long grain fill period.
- The traditional 3 spray programmes containing 3 strobilurins produced the highest yields, but high costs meant that 2 spray straddle approaches (applied at GS33 and GS55) gave equal margin over chemical costs.
- In both trials there was little difference in yield and disease control between Proline and Opus based programmes. However the slightly higher costs of the programmes containing Proline and Fandango resulted in slightly superior margins or Opus and Opus mixed with Comet in mid Canterbury.
- In south Canterbury, over the last 2 seasons, Proline at GS32 and GS39 alone followed by Amistar/Opus has given the best margin.