| Highlights from the 2003/2004 Winter Barley survey |
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- Total foliar disease levels were lower than 2003 and the second lowest during the last ten years.
- For the seventh successive year, Rhynchosporium leaf blotch was the most severe foliar disease, followed by mildew and net blotch respectively.
- Eyespot severity was low, although higher than in 2003 it was still below the 10-year mean.
- For the third successive survey, Pearl was the most common cultivar encountered (51% of crops).
- Sixty seven per cent of crops surveyed were sown in September with 42% of these sown before 24 September.
- Eyespot severity was lower in crops sown after 14 October, as indicated in all but one of the previous surveys.
- Ninety seven per cent of crops were treated with a fungicide, more than recorded in any previous survey.
- Each crop received on average 1.73 sprays, the second highest recorded.
- The DMI fungicides were most popular group used. Almost 90% of treated crops received at least one application. This follows two successive surveys when the strobilurin group of fungicides were most popular.
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| National and regional severity of diseases |
| The incidence of powdery mildew and levels on leaf 2 were higher in this survey than in any other since 1999, net blotch on leaf 2 was the highest for 4 years. Levels of Rhynchosporium
have decreased since 2000, this survey indicated the lowest levels on leaf 2 since 1995. |
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| Fig. 1 National foliar disease levels (mean % area leaf 2 affected) |
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| The highest levels of Rhynchosporium were recorded in the west midlands region. However, the disease was recorded more often in samples from the north east region. Only the
four major diseases were recorded in every region. Mildew severity was highest in the yorkshire and humber region and net blotch and brown rust in the south west. Of the minor diseases, where national levels were
at trace amounts, the incidence of Septoria nodorum was greatest in the south east region. Once again Selenophoma leaf spot was recorded only in samples from the south west. Yellow rust was not encountered in this survey. |
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| Fig. 2 Regional incidence and severity of Rhynchosporium |
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| Eyespot severity increased slightly compared to levels in 2003. However, since the high severity year of 2000, mean levels of damaging eyespot (moderate + severe), have been less than half
of the mean figure for the five years prior to 2000. |
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| Fig. 3 National incidence (% crops) and levels of eyespot (mean % stems affected) |
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| The lowest levels of damaging eyespot were recorded in the east and the highest levels in samples from the north west, north east and east midlands regions. Severe eyespot was recorded in samples from all regions. |
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| Fig. 4 Regional eyespot levels (mean % stems affected) |
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| Cultivar use |
| Pearl dominated the sample accounting for 51% of the crops surveyed, followed by Carat with only 14%. Of the seven most popular cultivars, the highest average level of Rhynchosporium was recorded on Heligan with 3.6% of leaf 2
affected and the lowest on Siberia with 0.1%. Levels of net blotch and powdery mildew were also highest on Heligan. Since 2001 participants in the survey have been asked whether disease resistance was a factor when selecting the variety and 36% per cent of respondents
gave a positive reply, a figure consistent with previous surveys. |
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| Fig. 5 Foliar diseases on main cultivars (mean % area leaf 2) |
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| Fungicide use |
| The DMIs proved to be the most popular fungicide group applied to crops, replacing, after two successive years, the strobilurin group. No crop received more than two applications of a strobilurin and 94% of strobilurin applications contained a partner DMI
either as part of a commercial product or as a tank mix. Over 61% of crops received a two-spray programme compared with 56% in 2003. Then mean number of sprays applied was 1.7, the second highest recorded to date. Eighty eight per cent of crops received a spray aimed at GS 31 with 70% of
these crops receiving a subsequent application at GS 37 onwards. |
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| Fig. 6 Fungicide use: per cent of treated crops receiving applications from the major fungicide groups post emergence. |
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| Fig. 7 Fungicide applications during the growing season |
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| Sowing dates |
| The majority of crops were sown before 1 October. The highest proportion of crops were sown during the last week of September reversing the trend seen in the previous two seasons.
Nineteen per cent of crops were grown from farm saved seed a slight decrease when compared with recent surveys. Once again eyespot less damaging in the later-sown crops. |
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| Fig. 8 Sowing dates of survey crops (%)
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