PROJECT REPORT No. 237

Transcription

1 PROJECT REPORT No. 237 THE RESPONSE OF SPRING BARLEY VARIETIES TO STROBILURIN FUNGICIDES OCTOBER 2000 Price 6.00

2 PROJECT REPORT No. 237 THE RESPONSE OF SPRING BARLEY VARIETIES TO STROBILURIN FUNGICIDES by R A BAYLES NIAB, Huntingdon Road, Cambridge, Cambridgeshire CB3 0LE The response of spring barley varieties to strobilurin fungicides This Report is the final of a report project of an funded eight month jointly project by HGCA which (Project started in Ref. April 2180) The work was funded jointly and by HGCA Zeneca (project Ltd. no ,237) and Zeneca Ltd ( 4,500). The Home-Grown Cereals Authority (HGCA) has provided funding for this project but has not conducted the research or written this report. While the authors have worked on the best information available to them, neither HGCA nor the authors shall in any event be liable for any loss, damage or injury howsoever suffered directly or indirectly in relation to the report or the research on which it is based. Rosemary Bayles, NIAB Reference herein to trade names and proprietary products without stating that they are protected does not imply that they may regarded as unprotected and thus free for general use. No endorsement of named products is intended nor is any criticism implied of other alternative, but unnamed products.

3 CONTENTS Page Summary 1 Background 3 Objectives 4 Methods 4 Results 9 Discussion 13 Tables (yield) 15 Figures 24 Appendix 1. Site data 33 Appendix 2. Disease and agronomic data 40

4 SUMMARY The responses of spring barley varieties to conventional fungicides and to fungicide programmes based on Amistar (a.i. azoxystrobin) were compared in five trials in England and one in Scotland. Two of these trials were deliberately harvested late in order to examine possible effects of Amistar on ear loss. Amistar-based fungicide programmes gave an average yield benefit over a full conventional programme of 0.45 t/ha (+6.3%) in the three main trials and 0.53 t/ha (+8.8%) in the two late-harvested trials. In the trial in Scotland, the benefit of a full Amistar-based programme over a comprehensive conventional programme was 0.37 t/ha (5.7%). Spring barley varieties that gave a high response to conventional fungicide programmes also gave a high response to Amistar programmes (e.g. Century and Prisma in trials in England and Optic and Henni in the Scottish trial). Similarly, varieties that gave a lower response to conventional fungicides tended to give a lower response to Amistar programmes (e.g. Static Riviera and Chariot in trials in England and Century and Delibes in the Scottish trial). The advantage of the Amistar programmes varied only slightly between varieties, ranging from 0.34 t/ha (+5.1%) for Prisma to 0.57 t/ha (+7.7 t/ha) for Century in England and from 0.23 t/ha (+3.6%) in Chariot and Cooper to 0.5 t/ha (+8.0%) in Newgrange in Scotland. As a result, the relative yields of varieties remained virtually unaffected by the change from conventional to strobilurin chemistry. The general implication for variety evaluation is that the overall relative performance of varieties is unlikely to be significantly affected by the introduction of strobilurin fungicides into the standard programme for Recommended List trials, although there may be exceptions in individual situations. Different spray timings and total application of Amistar were compared in the trials in England. Reducing the total application of Amistar to half its level in the full Amistar programme and reducing the number of sprays from two to one, did not reduce the yield advantage of these programmes over the conventional programme and led to improved margins over fungicide cost. This indicates the scope for cost effective exploitation of lower input strobilurin-based programmes in spring barley. The advantage of Amistar could be attributed at least in part to increased green leaf area retention. All varieties showed some increase in green leaf area from around GS75 onwards, when the comparison was made between Amistar-based and conventional programmes. Improved green leaf area retention might be the result of a) improved control of major diseases that are easily identified and routinely assessed, b) improved control of minor diseases that are less easily identified and not routinely assessed or c) physiological effects. In all of these trials the major diseases were well controlled by all programmes, with only very slight differences in efficacy. It therefore seems likely that control of minor pathogens and/or physiological effects contributed to the enhancement of green leaf area retention by the Amistar programmes. 1

5 Cooper suffered less ear loss than the other varieties, with Optic and Prisma suffering particularly high losses. This was in line with the vulnerability of these varieties to brackling, which was relatively slight in Cooper and very severe in Optic. The effects of variety on both brackling and ear loss were far greater than effects of fungicide treatment. Ear losses were not significantly affected by fungicide treatment and there was no evidence to support the suggestion that late applications of Amistar might reduce ear loss. Similarly, although brackling was generally reduced by all fungicide treatments, there was no consistent difference between the conventional and Amistar programmes. This was despite the fact that Amistar treatments did appear to keep stems greener for longer. 2

6 BACKGROUND Until the introduction of the strobilurin fungicides in 1997, cereal disease control had been almost entirely dependent on fungicides in the DMI and morpholine groups. Although there had been a steady improvement in the efficacy of products in these groups since the early 1980s, no alternative modes of action had been available. With the advent of the strobilurin fungicides the options available to the farmer broadened. Strobilurins represent a completely new class of fungicide chemistry, combining a novel mode of action with new mechanisms of uptake and translocation within the plant. In addition there is evidence that some strobilurins have beneficial physiological effects which, added to their fungicidal properties, result in improved preservation of green leaf area. As with conventional fungicides, variety is likely to have a major influence on the response of a crop to strobilurin fungicides. Variety responses to conventional fungicides have been thoroughly investigated in a range of projects, including the HGCA-funded Recommended List Trials and the Appropriate Fungicide Dose projects. It is now vital to generate comparable information on varietal responses to strobilurin fungicides, so that farmers can adapt their disease control strategies and utilise the new chemistry to best advantage. Varietal responses to strobilurins were investigated during 1998 for winter wheat and winter barley in an HGCA funded project at NIAB. The project demonstrated clearly the potential benefits of the new chemistry for a wide range of varieties of both these two crops. In general, varieties that gave low responses to conventional fungicides also gave relatively low responses to strobilurins, while varieties that gave high responses to conventionals also give high responses to strobilurins. Within this overall pattern certain varieties appeared to benefit more or less than might have been expected from their response to conventional fungicides. However, a second year s results indicated that many of these apparent interactions were inconsistent. The 1998 trials did not cover spring barley. This is the major barley crop in many regions of the UK and the acreage of spring barley nationally was approximately equivalent to that of winter barley in Spring barley is grown with lower fungicide inputs than winter barley and the size and range of variety responses to strobilurins is likely to be quite different. Ear loss can be a major problem in spring barley varieties, especially when harvest is delayed due to adverse weather conditions. In the south and south west there has been recent concern over disappointing yields due to ear loss. The two popular malting varieties Optic and Chariot, which between them occupy over 50% of the spring barley acreage, are both prone to this problem, having ratings for resistance to ear loss of only 6 (on a 1-9 scale). There is circumstantial evidence that the use of strobilurin fungicides may help to reduce ear loss. The mechanism for this is not clear, but could well be related delayed straw ripening. Greener straw would be expected to be less brittle and less liable to snap below the ear. Spring barley Recommended List variety trials were conducted with a strobilurin-based fungicide programme for the first time in It is clearly important to establish whether the relative performance of varieties is likely to change significantly as a result of the introduction of the new chemistry. 3

7 OBJECTIVES The objective of the project was to compare the responses of a range of spring barley varieties to fungicide programmes based on the strobilurin fungicide Amistar with their responses to programmes based on conventional products only. The project included an investigation of the effect of Amistar on ear loss in a range of spring barley varieties. METHODS There were two sets of trials. The first set (main trials) was designed to compare the response of varieties to conventional fungicides and to fungicide programmes based on Amistar (a.i. azoxystrobin) in terms of disease control, green leaf area maintenance and yield. The second set (delayed harvest trials) was aimed specifically at the problem of ear loss and the possible ameliorating effects of Amistar. These trials were harvested up to four weeks after the optimum date to increase the risk of ear loss. Main trials were sited at: Morley, Norfolk Seale-Hayne, Devon Wye, Kent Delayed harvest trials were sited at: Seale-Hayne, Devon Cockle Park, Northumberland The trial in Scotland was sited at Earlston, Berwickshire The varieties included both currently popular and newer varieties and represented a range of disease resistance and susceptibility to ear loss. There were seven varieties in the main trials, five in the delayed harvest trials and eight in the Scottish trial (Table 1). Table 1. Varieties included in spring barley variety x fungicide interaction trials, Main trials Delayed harvest trials Scottish trial Century Cooper Cooper Chariot Chariot Century Delibes Optic Chariot Optic Prisma Delibes Prisma Static Henni Riviera Static Newgrange Optic Prisma 4

8 Fungicide treatments Main trials There were six fungicide treatments in the main trials (Table 2). These comprised an untreated control (1), a high input standard treatment based on conventional chemistry (2), a comparable high input treatment based on Amistar Pro (3) and three treatments exploiting lower inputs of Amistar or Amistar Pro (4-6). The standard treatments 2 and 3 were similar to those used in NIAB spring barley variety trials with the aim being to limit disease to less than 5% infection in the most susceptible varieties under high disease pressure. Delayed harvest trials There were four fungicide treatments in the delayed harvest trials (Table 3), comprising an untreated control (1), a programme based on conventional chemistry (2) and two programmes based on Amistar Pro (3,4). Scottish trial There were three treatments (Table 4) comprising an untreated control (1), a programme based on conventional triazole and morpholine chemistry (2) and a strobilurin programme based on Amistar Pro (3). 5

9 Table 2. Fungicide programmes for main trials. Treatment Number 1 GS25/30 GS30/31 GS33* GS39-49** GS45-59*** Untreated Punch C (0.625 l/ha) Opus Team (1.5 l/ha) Tilt (0.5 l/ha) Corbel (0.75 l/ha) Patrol (0.5 l/ha) Amistar Pro (2.0 l/ha) Amistar Pro (2.0 l/ha) Unix (0.67 kg/ha) Bravocarb (1.0 l/ha) Amistar (0.8 l/ha) Fortress (0.15 l/ha) 5 6 Amistar (0.6 l/ha) Amistar (0.6 l/ha) Fortress (0.15 l/ha) Unix (0.4 kg/ha) Amistar Pro (2.0 l/ha) Unix (0.67 kg/ha) * - some flexibility depending on disease pressure ** - at latest when tips of awns just showing in earliest variety *** - awns emerged on latest variety Optional treatment shown in italics was applied at Seale-Hayne only, in response to late disease pressure. 6

10 Table 3. Fungicide programmes for delayed harvest trials. Treatment Number GS30/31 GS45 1 Untreated Punch C (0.625 l/ha) Opus Team (1.5 l/ha) Corbel (0.75 l/ha) 3 Amistar Pro (2.0 l/ha) Amistar Pro (2.0 l/ha) Unix (0.4 kg/ha) 4 Amistar Pro (2.0 l/ha) Amistar Pro (1.0 l/ha) Unix (0.4 kg/ha) Table 4. Fungicide programmes for Scottish trial Treatment Number GS GS Untreated Untreated 2 Punch C l/ha Corbel 0.75 l/ha 3 Amistar Pro 2.0 l/ha Unix 0.67 l/ha Opus Team 1.5 l/ha Tilt 0.5 l/ha Torch 1.0 l/ha Amistar Pro 2.0 l/ha Trial design The main and delayed-harvest trials were designed as randomised split plots with three replicates. Fungicide treatments were allocated to main plots and varieties to sub-plots. The Scottish trial was a randomised block with four replicates. Plot size varied between trials, within the range 12m x 2m to 20m x 2m. General husbandry was in accordance with local good farm practice. 7

11 Assessment of disease and green leaf area Main trials Foliar diseases were assessed in untreated plots just before each spray and in all plots at GS70/75. Assessments made before GS70 were carried out using the NIAB whole plot assessment key (i.e. a single assessment based on an average of all leaf layers). Assessments at GS70/75 were made on individual leaf layers (i.e. flag, leaf 2, leaf 3 and leaf 4 separately). Ear diseases were assessed at GS The percentage of leaf area remaining green was assessed once, at around GS75, for each leaf layer individually. Delayed harvest trials Foliar diseases were assessed in untreated plots just before each spray and in all plots at GS70/75. All assessments GS70 were made using the NIAB whole plot assessment key (i.e. a single assessment based on an average of all leaf layers). Ear diseases were assessed at GS Scottish trial Foliar disease and percentage green leaf area were assessed seven times, at GS30, GS32-39, GS61-64, GS61-68, GS67-75, GS77-80 and GS The first three assessments were made on a whole plot basis and the final four assessments by leaf layer. Other assessments Main trials Lodging, brackling and necking were assessed at GS75 and at harvest. Plots were combine harvested for yield determination and grain samples taken for dry matter determination by oven drying. Delayed harvest trials Lodging, brackling and necking were assessed at GS75 and at harvest. Stem greeness was assessed visually at GS75 and GS85. Ear loss was assessed visually on the standing plot prior to combining and by quadrat counts of ears lying on the ground after combining. Plots were combine harvested for yield determination and grain samples taken for dry matter determination by oven drying. Scottish trial Leaning, lodging, brackling and necking were assessed at GS Stem greeness was assessed twice, at GS75 and at GS85. Site and chemical application details are given for each trial in Appendix 1. 8

12 RESULTS Assessments of disease and green leaf area are tabulated in Appendix 2. Disease incidence and severity Table 5 indicates the disease severity in untreated plots of susceptible varieties in each trial. The dominant foliar disease in the East (Morley and Wye) was brown rust, with rhynchosporium dominant in the north (Cockle Park, Earlston). Mildew was present at variable levels at all sites except Seale-Hayne. Net blotch was found at moderate to severe levels at Seale-Hayne and slight levels at Earlston. Table 5. Severity of disease in spring barley trials (blank = absent / trace * = slight ** = moderate *** = severe **** = very severe) Main trials Delayed harvest Scotland Morley Seale- Hayne Wye Cockle Park Seale- Hayne Earlston Mildew ** * **** ** Brown rust ** *** Rhynchosporium * *** **** ** **** Net blotch *** ** * Disease control Mildew Main trials: Morley was the only trial in which mildew was still present at low levels in Prisma at GS75. All fungicide treatments reduced mildew to much the same degree, but with an indication that 4 was slightly less effective than the other programmes. Delayed harvest: At Cockle Park mildew was very severe in untreated plots of Prisma and all fungicide programmes gave good control. Earlston: Mildew at the GS32-39 stage was well controlled by the first fungicide application in both treatments 2 and 3. Later in the season mildew largely disappeared from untreated plots. Brown rust Main trials: At Wye, all treatments gave complete conrol of brown rust. At Morley control was almost complete, with an indication that treatment 4 may have been slightly less effective than other treatments. Rhynchosporium Main trials: At Seale-Hayne, all treatments gave almost complete control of Rhynchosporium. At Morley, levels of the disease were lower, but control was less complete on leaves 2 and 3, with an indication that treatments 4 and 5 may have been slightly less effective than other treatments. Delayed harvest: All treatments gave good control of Rhynchosporium in both trials, 9

13 Earlston: Both fungicide programmes gave a very high degree of control of Rhynchosporium on all leaf layers, under severe disease pressure. Net blotch Main trials: All treatments gave equally good control of net blotch at Seale Hayne Delayed harvest: All treatments appeared to give equally good control of net blotch in the Seale-Hayne trial. Earlston: Levels of net blotch infection were too low to judge whether there was any differential effect of fungicide treatment. Green Leaf Area Main trials Assessments of green leaf area during grain ripening (GS75-80) indicated that all fungicide programmes substantially increased green leaf area retention in all leaf layers when compared with the untreated control (Fig.1). Amistar-based programmes (3-6) generally had a slight advantage in this respect. The conventional fungicide programme increased green leaf area at by an average of 28%, with the comparable figure for the mean of the Amistar programmes being 36%, an improvement of 8%. This advantage was similar in all top 3 leaf layers. There was a range of varietal responses (Fig. 2), with Chariot showing the lowest improvement with both conventional and Amistar programmes (18% and 29% respectively) and Century the greatest improvement (41% and 50%). The benefit of Amistar programmes compared with the conventional programme was least in Riviera (2.5%) and greatest in Optic (13.3%). Delayed harvest trials Fungicide application greatly increased the percentage of the leaf remaining green at GS75-80 (Fig. 3), but there was no clear difference between the conventional programme (1) and the two Amistar programmes (3,4). Scottish trial Both the conventional (2) and Amistar programme (3) increased green leaf area retention at GS 75/80 in all leaf layers when compared with the untreated control (1) (Fig. 4). The Amistar-based programme generally had an overall advantage in this respect. The conventional fungicide programme increased green leaf area by an average of 40%, with the comparable figure for the Amistar programme being 51%, an improvement of 11%. The advantage of the Amistar programme varied between leaf layers, being greatest on the flag leaf (mean increase =26%) and relatively slight on leaf 2 (mean increase = 9%). No advantage of the Amistar programme (3) was seen on leaf 3. There was a range of varietal responses (Fig. 5). Optic and Henni gave the largest green leaf responses to both fungicide programmes, whilst Newgrange gave the least response to the conventional programme and Delibes to the Amistar programme. The benefit of the Amistar programme compared with the conventional programme was least in Delibes (15%) and greatest in Newgrange (46%). 10

14 Lodging Main trials There was moderate to severe lodging in the Morley trial. This was most severe in Optic, Prisma and Riviera and least severe in Century and Delibes. Lodging was most severe with the conventional treatment 2 and the Amistar treatment 4 and least severe in untreated plots. Delayed harvest trials There was no lodging in either trial. Scottish trial There was no lodging in this trial. Stem greeness Delayed harvest trials In the Cockle Park trial, all fungicide treatments increased stem greeness. Although there was little difference between the conventional and Amistar treatments at GS75, by GS85 stems were generally greener with the two Amistar treatments. In the Seale-Hayne trial, all treatments increased stem greeness at GS85, with an indication that 3, the treatment with the higher rate of Amistar Pro at GS45, resulted in slightly greener stems than the other two treatments, 2 and 4. Scottish trial Both fungicide programmes increased stem greeness. There was no overall difference between the conventional and Amistar programmes at GS75/80, but by GS 85 a difference had emerged, with stems remaining slightly greener with the Amistar programme. Brackling Main trials Only the trial at Wye was affected by brackling. This was most severe in Optic and least severe in Riviera and Static. Brackling was most severe in untreated plots and those receiving the Amistar treatment 6 (no fungicide after GS33) and least severe in the conventional treatment 2 and the Amistar treatment 5. Delayed harvest trials There was little or no brackling in either trial when first assessed in mid July early August. However, when assessed immediately before the delayed harvest in mid September, brackling was severe in both trials (Fig. 7). All fungicide programmes reduced brackling, but there was no consistent difference between the conventional and Amistar programmes. There were clear differences between varieties, with Optic being the most severely, and Cooper the least severely, brackled. Scottish trial There was no brackling. 11

15 Ear loss Delayed harvest trials Ear losses, whether estimated visually before harvest or by counting ears on the ground after harvest, were unaffected by fungicide treatment in either trial (Figs 8 and 9). There were significant differences between varieties in both trials. Cooper had consistently low ear losses and Optic and Prisma high ear losses. Yield Main trials (Mean over trials: Table 5.1. Individual sites: Tables ) The conventional control treatment 2 gave an average yield increase of 1.08 t/ha (+19.1%) over untreated. This response varied from 0.58 t/ha (+7.9%) in Static to 1.70 t/ha (+30.0%) in Century (Fig.6). There were no significant differences in yield between the four Amistarbased treatments (3-6), which gave an average increase over the conventional treatment of 0.45 t/ha (+6.3%). The advantage of the Amistar treatments varied only slightly between varieties, ranging from 0.34 t/ha (+5.1%) in Prisma to 0.57 t/ha (+7.7%) in Century. Delayed harvest trials (Tables ) The effects of fungicide treatment on yield were not statistically significant in either of the two trials, probably due to increased variability within the trial resulting from late harvesting. However, there was a clear trend for the Amistar treatments 3 and 4 to improve yield compared with the conventional treatment 2. The mean advantage of the Amistar treatments was 0.53 t/ha (+8.8%), similar to that in the main trials. Scottish trial (Table 5.7) The conventional programme gave an average yield increase of 1.17 t/ha (+22%) over the untreated. The Amistar-based programme gave an additional increase over the conventional programme of 0.37 t/ha (5.7%). The advantage of the Amistar programme varied from 0.23 t/ha (+3.6%) in Chariot and Cooper to 0.5 t/ha (+8.0%) in Newgrange. Economic analysis Tables 6.1 to 6.4 give estimates of margins over fungicide cost for the main and scottish trials. In the main trials, treatment (4), the lowest cost programme, was the most cost effective over all, giving a substantially higher margin over fungicide costs than the full strobilurin control treatment (3). Treatment (3) was more cost effective than the full conventional programme (2), by a margin of around 10/ha-16/ha. In the Scottish trial, the full strobilurin treatment (3) was more cost effective than the full conventional treatment (2) by a similar margin. In all trials, the high input programmes (2) and (3) gave little or no advantage over the untreated (1), particularly at feed grain prices. 12

16 DISCUSSION Previous HGCA-funded and commercial trials at NIAB have demonstrated the yield advantages of strobilurin fungicides across a wide range of varieties of winter wheat and winter barley. In a series of five variety trials in 1998, strobilurin-based fungicide programmes were compared with programmes using conventional chemistry only. The advantage of the strobilurin programmes averaged 1.20 t/ha (+13.6%) for winter wheat and 0.44 t/ha (6.7%) for winter barley. In a similar series of trials in 1999, the corresponding figure for winter wheat was considerably lower, at 0.35 t/ha (+3.7%), while the figure for winter barley was slightly higher, at 0.55 t/ha (+10.4%). This project has now demonstrated the benefits of strobilurin fungicides for spring barley varieties. In a series of three trials in England, four fungicide programmes based on the strobilurin azoxystrobin (Amistar) gave an average yield benefit over a full conventional programme of 0.45 t/ha (+6.3%). In two further trials, one in the south west and one in the north of England, two Amistar-based treatments gave benefits averaging 0.53 t/ha (+8.8%). In a similar trial in Scotland, the benefit of a full Amistar-based programme over a comprehensive conventional programme was 0.37 t/ha (5.7%). The evidence therefore indicates that the potential benefits for the spring barley crop are on the same scale as for winter barley. Spring barley varieties that gave a high response to conventional fungicide programmes also gave a high response to Amistar programmes (e.g. Century and Prisma in trials in England and Optic and Henni in the Scottish trial). Similarly, varieties that gave a lower response to conventional fungicides tended to give a lower response to Amistar programmes (e.g. Static Riviera and Chariot in trials in England and Century and Delibes in the Scottish trial). The advantage of the Amistar programmes varied only slightly between varieties, ranging from 0.34 t/ha (+5.1%) for Prisma to 0.57 t/ha (+7.7 t/ha) for Century in England and from 0.23 t/ha (+3.6%) in Chariot and Cooper to 0.5 t/ha (+8.0%) in Newgrange in Scotland. As a result, the relative yields of varieties remained virtually unaffected by the change from conventional to strobilurin chemistry. The only apparent exception to this was the performance of Newgrange in the Scottish trial. This variety, which gave a relatively low response to conventional fungicides and high response to Amistar, improved its performance relative to other varieties with the Amistar-based programme. However, this result from a single trial should be interpreted with caution. From the point of view of variety evaluation, the general indication is that the overall relative performance of varieties is unlikely to be significantly affected by the introduction of strobilurin fungicides into the standard programme for Recommended List trials, although there may be exceptions in individual situations. Different spray timings and total application of Amistar were compared in the trials in England. Reducing the total application of Amistar to half its level in the full Amistar programme and reducing the number of sprays from two to one, did not reduce the yield advantage of these programmes over the conventional programme and led to improved margins over fungicide cost. This indicates the scope for cost effective exploitation of lower input strobilurin-based programmes in spring barley. The advantage of Amistar could be attributed at least in part to increased green leaf area retention. All varieties showed some increase in green leaf area from around GS75 onwards, when the comparison was made between Amistar-based and conventional programmes. Improved green leaf area retention might be the result of a) improved control of major diseases that are easily identified and routinely assessed, b) improved control of minor 13

17 diseases that are less easily identified and not routinely assessed or c) physiological effects. In all of these trials the major diseases were well controlled by all programmes, with only very slight differences in efficacy. It therefore seems likely that control of minor pathogens and / or physiological effects contributed to the enhancement of green leaf area retention by the Amistar programmes. Ear loss can be an important factor in reducing yields in spring barley varieties, especially when harvest is delayed due to adverse weather conditions. Ears may snap off in the standing crop before harvest, or be lost during combining, the latter being referred to as cutter bar losses. In two of these trials the risk of ear loss was increased by purposely delaying harvest. Two estimates of ear loss were made. The first was a visual estimate made before harvest of the percentage of tillers that had lost their ears. The second was a count of ears lying on the ground after harvest, which would include both pre-harvest losses and additional losses during combining. It was clear from both estimates that the variety Cooper suffered less from ear loss than the other varieties and that Optic and Prisma suffered particularly high losses. This was in line with the vulnerability of these varieties to brackling, which was relatively slight in Cooper and very severe in Optic. The effects of variety on both brackling and ear loss were far greater than effects of fungicide treatment. Ear losses were not significantly affected by fungicide treatment and there was certainly no evidence to support the suggestion that late applications of Amistar might reduce ear loss. Similarly, although brackling was generally reduced by all fungicide treatments, there was no consistent difference between the conventional and Amistar programmes. This was despite the fact that Amistar treatments did appear to keep stems greener, and therefore presumably less brittle, for longer. It appears that any possible benefit of this was lost before the very delayed harvest. 14

18 Table 5.1. Main trials. Yield (t/ha). Mean over 3 trials. Treatment Century Chariot Delibes Optic Prisma Riviera Static Mean Mean Significance: Treatment effect *** Variety effect *** Site effect *** Treatment x Variety interaction *** Treatment x Site interaction *** Variety x Site interaction *** lsd treatment means = lsd variety means = lsd variety means within treatment = lsd treatment means within variety = NS = non significant * = significant at P = 0.05 ** = significant at P = 0.01 *** = significant at P =

19 Table 5.2 Main trials. Yield (t/ha) Morley Treatment Century Chariot Delibes Optic Prisma Riviera Static Mean Mean Significance: Treatment effect *** Variety effect *** Treatment x Variety interaction *** lsd treatment means = lsd variety means = lsd variety means within treatment = lsd treatment means within variety = NS = non significant * = significant at P = 0.05 ** = significant at P = 0.01 *** = significant at P =

20 Table 5.3 Main trials. Yield (t/ha) Seale-Hayne Treatment Century Chariot Delibes Optic Prisma Riviera Static Mean Mean Significance: Treatment effect *** Variety effect *** Treatment x Variety interaction NS lsd treatment means = lsd variety means = lsd variety means within treatment = lsd treatment means within variety = NS = non significant * = significant at P = 0.05 ** = significant at P = 0.01 *** = significant at P =

21 Table 5.4 Main trials. Yield (t/ha) Seale-Hayne Treatment Century Chariot Delibes Optic Prisma Riviera Static Mean Mean Significance: Treatment effect NS Variety effect *** Treatment x Variety interaction ** lsd treatment means = lsd variety means = lsd variety means within treatment = lsd treatment means within variety = NS = non significant * = significant at P = 0.05 ** = significant at P = 0.01 *** = significant at P =

22 Table 5.5 Delayed harvest trials. Yield (t/ha) Cockle Park Treatment Chariot Cooper Optic Prisma Static Mean Mean Significance: Treatment effect NS Variety effect NS Treatment x Variety interaction NS lsd treatment means = lsd variety means = lsd variety means within treatment = lsd treatment means within variety = NS = non significant * = significant at P = 0.05 ** = significant at P = 0.01 *** = significant at P =

23 Table 5.6 Delayed harvest trials. Yield (t/ha) Morley Treatment Chariot Cooper Optic Prisma Static Mean Mean Significance: Treatment effect NS Variety effect *** Treatment x Variety interaction ** lsd treatment means = lsd variety means = lsd variety means within treatment = lsd treatment means within variety = NS = non significant * = significant at P = 0.05 ** = significant at P = 0.01 *** = significant at P =

24 Table 5.7 Scottish Trial (Earlston) Yield t/ha Treatment Prisma Optic Chariot Cooper Century Newgrange Delibes Henni Mean Mean Significance: Treatment effect *** Variety effect * Treatment x Variety effect NS lsd treatment means = lsd variety means = 1.43 lsd variety means within treatment = lsd treatment means within variety =

25 Table 6.1. Main trials: Margin over fungicide cost ( /ha). Feed grain price ( 62 / tonne). Century Chariot Delibes Optic T T T T T T Prisma Riviera Static Mean Mean Table 6.2: Main trials: Margin over fungicide cost ( /ha). Malting grain price ( 72 / tonne). Century Chariot Delibes Optic T T T T T T Prisma Riviera Static Mean Mean

26 Table 6.3 Scottish trial: Margin over fungicide cost ( /ha). Feed grain price ( 62 / tonne). Treatment Century Chariot Cooper Delibes Henni Newgrange Optic Prisma Mean Mean Table 6.4: Scottish trial: Margin over fungicide cost ( /ha). Malting grain price ( 72 / tonne). Treatment Century Chariot Cooper Delibes Henni Newgrange Optic Prisma Mean Mean

27 Fig. 1 Main trials. Percentage leaf area remaining green at GS75-80 (mean of 7 varieties) flag leaf 2 leaf 3 leaf 4 Morley Seale-Hayne % GLA % GLA Fungicide programme Fungicide programme Wye 80 % GLA Fungicide programme 24

28 Fig. 2 Main trials. Effect of variety and fungicide programme on Green Leaf Area, GS75 (mean of top 3/4 leaves; 3 trials) Green Leaf % mean CHARIOT DELIBES STATIC OPTIC RIVIERA PRISMA CENTURY 25

29 Fig. 3 Delayed-harvest trials. Percentage leaf area remaining green at GS75-80 (mean of 5 varieties) whole plant Cockle Park % GLA Fungicide programme Seale-Hayne % GLA Fungicide programme 26

30 Fig. 4 Earlston. Percentage leaf area remaining green during grain filling (mean of 7 varieties) fla leaf leaf 100 GS 67/75 GS 77/80 GS 80/85 80 % GLA Fungicide programme 27

31 Fig. 5 Earlston. Effect of variety and fungicide programme on Green Leaf Area, GS (mean of top 3 leaves; 3 assessments) Green Leaf % Newgrange Prisma Delibes Chariot Century Cooper Optic Henni 28

32 Fig. 6 Main trials. Effect of variety and fungicide programme on yield (mean of 3 trials) 8 Yield t/ha mean STATIC RIVIERA CHARIOT DELIBES OPTIC PRISMA CENTURY 29

33 Fig. 7 Delayed Harvest trials. Effect of variety and fungicide programme on Brackling. 100 Cockle Park Brackling % CHARIOT COOPER OPTIC PRISMA STATIC Seale-Hayne Brackling % CHARIOT COOPER OPTIC PRISMA STATIC 30

34 Fig. 8 Delayed Harvest trials. Effect of variety and fungicide programme on ear loss % 4 Cockle Park Ear loss % CHARIOT COOPER OPTIC PRISMA STATIC Seale-Hayne 7 6 Ear loss % CHARIOT COOPER OPTIC PRISMA STATIC 31

35 Fig. 7 Delayed harvest trials Effect of variety and fungicide programme on ear loss per m 2 15 Cockle Park Ear loss per m CHARIOT COOPER OPTIC PRISMA STATIC 80 Seale-Hayne 60 Ear loss per sq m CHARIOT COOPER OPTIC PRISMA STATIC 32

36 APPENDIX 1. Site and chemical application data. SOIL TYPES TEXTURAL GROUP SYMBOL SOIL TEXTURE Sands CS coarse sand S sand FS fine sand LCS loamy coarse sand Very Light Soils LS loamy sand LFS loamy fine sand CSL coarse sandy loam Light Soils SL sandy loam FSL fine sandy loam SZL sandy silt loam ZL silt loam Medium Soils SCL sandy clay loam CL clay loam ZCL silty clay loam Heavy Soils SC sandy clay C clay ZC silty clay Based on 'Soil Texture System', published by MAFF/ADAS pamphlet SOIL DRAINAGE TYPE Free Imperfect Poor SYMBOL F I P PREVIOUS CROP CROP SYMBOL CROP SYMBOL W WHEAT WW S BEET SBT W BARLEY WB WO RAPE WOR S BARLEY SB GRAIN PEAS GPS W OATS WO FORAGE PEAS FPS S OATS SO LINSEED LIN W BEAN WBN POTATOES POT S BEAN SBN GRASS G 33

37 APPENDIX 1 SPRING BARLEY Site Name MORLEY Trial ID SB9EE31T Grid Ref TM Eastings 990 Northings 57 Altitude 50 Previous Cropping SBT WBN WW WW SBT Soil texture SCL Drainage F Sowing date 23-Feb-99 Applications: Date GS Product Rate Fertiliser 09-Apr N TOP DRESSING KG/HA 12-Apr Mg 2 KG/HA Herbicide 01-May ALLY 01-May DUPLOSAN Insecticide PGR Fungicide T1 * * * * T2 19-May CORBEL 0.75 L/HA 19-May PUNCH C L/HA 09-Jun OPUS TEAM 1.5 L/HA T3 19-May AMISTAR PRO 2 L/HA 19-May UNIX 0.67 KG/HA 15-Jun AMISTAR PRO 2 L/HA T4 30-Apr BRAVOCARB 1 L/HA 30-Apr FORTRESS 0.15 L/HA 09-Jun AMISTAR 0.8 L/HA T5 19-May AMISTAR 0.6 L/HA 19-May FORTRESS 0.15 L/HA 15-Jun AMISTAR 0.6 L/HA 15-Jun UNIX 0.4 KG/HA T6 28-May AMISTAR PRO 2 L/HA 28-May UNIX 0.67 KG/HA 34

38 APPENDIX 1 SPRING BARLEY Site Name SEALE-HAYNE Trial ID SB9SW33T Grid Ref SX Eastings 767 Northings 629 Altitude 50 Previous Cropping SBN SB WB G Soil texture SCL Drainage F Sowing date 26-Mar-99 Applications: Date GS Product Rate Fertiliser 23-Apr N TOP DRESSING 1 88 KG/HA 29-Apr P2O5 63 KG/HA 29-Apr K2O 94 KG/HA Herbicide 26-May JUBILEE 26-May QUANTUM Insecticide PGR 08-Jun TERPAL Fungicide T1 * * * * T2 01-Jun CORBEL 0.75 L/HA 01-Jun PUNCH C L/HA 14-Jun OPUS TEAM 1.5 L/HA 21-Jun PATROL 0.5 L/HA 21-Jun TILT 0.5 L/HA T3 01-Jun AMISTAR PRO 2 L/HA 01-Jun UNIX 0.67 KG/HA 21-Jun AMISTAR PRO 2 L/HA T4 27-May BRAVOCARB 1 L/HA 27-May FORTRESS 0.15 L/HA 14-Jun AMISTAR 0.8 L/HA T5 01-Jun AMISTAR 0.6 L/HA 01-Jun FORTRESS 0.15 L/HA 21-Jun AMISTAR 0.6 L/HA 21-Jun UNIX 0.4 KG/HA T6 06-Jun AMISTAR PRO 2 L/HA 06-Jun UNIX 0.67 KG/HA 35

39 APPENDIX 1 SPRING BARLEY Site Name WYE Trial ID SB9S32T Grid Ref TR Eastings 215 Northings 594 Altitude 15 Previous Cropping WW POT SB WW Soil texture ZL Drainage I Sowing date 17-Mar-99 Applications: Date GS Product Rate Fertiliser 11-Feb-99 0 N BASAL 50 KG/HA 19-Apr N TOP DRESSING 1 32 KG/HA 11-Feb-99 0 P2O5 25 KG/HA 11-Feb-99 0 K2O 25 KG/HA Herbicide 08-May ALLY 08-May CMPP 08-May HBN Insecticide 08-May CYPERMETHRIN PGR Fungicide T1 * * * * T2 10-May CORBEL 0.75 L/HA 10-May PUNCH C L/HA 01-Jun OPUS TEAM 1.5 L/HA T3 10-May AMISTAR PRO 2 L/HA 10-May UNIX 0.67 KG/HA 08-Jun AMISTAR PRO 2 L/HA T4 04-May BRAVOCARB 1 L/HA 04-May FORTRESS 0.15 L/HA 01-Jun AMISTAR 0.8 L/HA T5 10-May AMISTAR 0.6 L/HA 10-May FORTRESS 0.15 L/HA 08-Jun AMISTAR 0.6 L/HA 08-Jun UNIX 0.4 KG/HA T6 28-May AMISTAR PRO 2 L/HA 28-May UNIX 0.67 KG/HA 36

40 APPENDIX 1 SPRING BARLEY Site Name COCKLE PARK (DELAYED HARVEST) Trial ID SB9N36T Grid Ref NZ Eastings 203 Northings 912 Altitude 99 Previous Cropping WB SO WB WW WW Soil texture SCL Drainage I Sowing date 19-Mar-99 Harvest date 14-Sep-99 Applications: Date GS Product Rate Fertiliser 08-Apr N TOP DRESSING 1 85 KG/HA 10-Sep-98 P2O5 75 KG/HA 10-Sep-98 K2O 75 KG/HA Herbicide 19-May ALLY Insecticide PGR Fungicide T1 * * * * T2 20-May CORBEL 0.75 L/HA 20-May PUNCH C L/HA 21-Jun OPUS TEAM 1.5 L/HA T3 20-May AMISTAR PRO 2 L/HA 20-May UNIX 0.4 KG/HA 21-Jun AMISTAR PRO 2 L/HA T4 20-May AMISTAR PRO 2 L/HA 20-May UNIX 0.4 KG/HA 21-Jun AMISTAR PRO 1 L/HA 37

41 APPENDIX 1 SPRING BARLEY Site Name SEALE-HAYNE (DELAYED HARVEST) Trial ID SB9SW35T Grid Ref SX Eastings 767 Northings 628 Altitude 60 Previous Cropping SBN SB WB G G Soil texture SCL Drainage F Sowing date 19-Mar-99 Harvest date 10-Sep-99 Applications: Date GS Product Rate Fertiliser 08-Apr N TOP DRESSING 1 85 KG/HA 10-Sep-98 P2O5 75 KG/HA 10-Sep-98 K2O 75 KG/HA Herbicide 19-May ALLY Insecticide PGR Fungicide T1 * * * * T2 01-Jun CORBEL 0.75 L/HA 01-Jun PUNCH C L/HA 21-Jun OPUS TEAM 1.5 L/HA T3 01-Jun AMISTAR PRO 2 L/HA 01-Jun UNIX 0.4 KG/HA 21-Jun AMISTAR PRO 2 L/HA T4 01-Jun AMISTAR PRO 2 L/HA 01-Jun UNIX 0.4 KG/HA 21-Jun AMISTAR PRO 1 L/HA 38

42 APPENDIX 1 Site: Fans Farm, Earlston, Berwickshire Grid Ref: NT Elevation: 185 m Soil Series: Hobkirk Soil Type: Sandy Loam Previous Cropping: 1998 Spring Barley 1997 Winter Wheat 1996 Potatoes 1995 Winter Wheat Soil Analysis: ph 6.3 P High K Moderate Mg Moderate S Low Mn Moderate Sowing Date: 19 March, 1999 Seed Rate: 425 seeds/m 2 Varieties: Cooper, Newgrange, Optic, Century, Henni, Chariot, Prisma, Delibes Trial Design: Randomised block (4 blocks) Plot Size: 16m x 2m Fertiliser: (22 March, 1999) 58 kg/ha N (19 April. 1999) Herbicide: 3.5 l/ha Swipe (4th May, 1999) Fungicide Treatments: GS (Applied 10th June, 1999) 2 PunchC l/ha + Corbel 0.75 l/ha 3 Amistar pro 2.0 l/ha + Unix 0.67 l/ha GS (Applied 25 June,1999) 2 Opus Team 1.5 l/ha 3 Amistar pro