Spot form net blotch management

Transcription

1 Spot form net blotch management Background Spot form net blotch SFNB (Pyrenophora teres f maculata) is a key disease of barley in the northern region. It is a stubble-borne disease that has been favoured by the increasing level of stubble retention practised throughout the area combined with a lack of varieties with adequate resistance. Although it is generally regarded as a disease of wet seasons, agronomists in northern areas have noticed concerning levels of disease development, even in recent drier years. Plant breeding represents the most effective method of long term disease management together with an increase in rotation interval between barley crops. However, fungicides are an important tool that will enable disease management in varieties without effective SFNB resistance but possessing other desirable agronomic attributes. Current industry guidelines for fungicide timing are to delay application until close to flag leaf emergence. However many experienced advisers have been concerned that these recommendations may need review given recent application timing experiences for stripe rust management and the generally early onset of SFNB infection. Although this project was focused on SFNB management, an opportunity arose in 2008 to evaluate the same treatments on the closely related net form net blotch NFNB (Pyrenophora teres f teres). Only one trial has been conducted on this disease but the information included because of the similarity to SFNB. Grower Needs First 1

2 Project aims In 2007: 1. Identify the impact from spot form of net blotch on yield and grain quality of commercial varieties under regional conditions 2. Evaluate whether there is any benefit in fungicide application prior to flag leaf emergence for this disease 3. Provide additional data to support commercial management practices In 2008: 1. Further evaluate the impact of application timing on disease management and economic return 2. Compare the efficacy and economic benefits of single and multiple application 3. Investigate the potential of a new fungicide for SFNB management Spot form net blotch symptoms at harvest, variety Skiff, North Star 2007 Grower Needs First 2

3 Contents Background... 1 Project aims... 2 Results in a nutshell... 4 Trial design... 5 Assessments... 5 Multi-trial summary... 7 Disease levels... 7 Yield impact... 8 Quality impact... 9 Economic impact Individual trial results Individual trial results Tilt and Amistar Xtra are registered trademarks of a Syngenta Group Company Prosaro is a registered trademark of Bayer Hasten is a registered trademark of Victorian Chemicals Grower Needs First 3

4 Results in a nutshell Disease control: Single timing: in these trials the most effective SFNB (and NFNB) suppression was from application during early stem elongation (~GS30-32). Optimal timing may vary when high levels of late season rain are experienced Multiple application timing: more effective SFNB (and NFNB) suppression than single application. Most effective generally ~GS31-32 followed by later spray No consistent rate response to Tilt and no clear benefit from alternative chemistry Yield impact: Variable SFNB yield response: Good benefits in both trials in 2007 (mean kg/ha) but no yield benefit in two trials in NFNB trial had mean 338 kg/ha benefit Grain quality impact: Clear trend to reduced quality due to SFNB in all trials SFNB increased average screenings by ~10 to 15% at 3 of 4 sites SFNB reduced average retention by ~6 to 20% across all sites SFNB reduced test weight by ~2 to 4 kg/hl across all sites Overall: Correct identification of SFNB is a major issue with many similar non disease blotches occurring in barley Fungicide application during early stem elongation provided the most consistent disease suppression Economic impact of SFNB was variable with average net benefits of ~$60 to $100/ha in 2007 but net losses of ~$6 to $20/ha in 2008 SFNB resulted in reduced grain quality in all trials Grower Needs First 4

5 Trial design 2007: Two replicated small plot trials were established in commercial barley crops in the North Star and Bellata districts. Trials were conducted on the varieties Skiff (North Star) and Kaputar (Bellata) which are both rated as susceptible to SFNB. Both crops were planted into 2006 barley stubble with SFNB naturally present before first application. Individual plot size was 4m x 10m with an untreated buffer area of 2m width between plots. Eleven different fungicide programs were evaluated over three replicates. Plots were sprayed with an ATV mounted 4m boom. DG nozzles were used at 230 kpa, 12.3 km/hr and a volume of 50 L/ha. The droplet size produced at these parameters is rated as Fine/ Medium (ASAE standard S-572). Multiple applications received the indicated product rate at each designated timing. Fungicide Program Product Product rate Timing Tilt Single application 250 ml/ha T2 and T3 500 ml/ha T1, T2 and T3 Amistar Xtra 400 ml/ha T2 and T3 250 ml/ha x 2 T1+T2 and T2+T3 Multiple Tilt 250 ml/ha x 3 T1+T2+T3 application 500 ml/ha x 2 T2+T3 T1 = Timing 1 etc Assessments 1. SFNB severity: severity visual rating of % leaf area diseased on top 3 leaves in 10 random main tillers/plot (incidence - % leaves with any SFNB presence also assessed but not presented) 2. Yield and grain quality: all plots were harvested by small plot header with grain quality analysis conducted by the QDPI&F grain quality laboratory Grower Needs First 5

6 Disease assessment was made on the uppermost fully emerged 2 or 3 leaves on 10 random main tillers in each plot at approximately 2 week intervals from first spray timing for a minimum of 7 weeks. 2008: Four replicated small plot trials were established in commercial barley crops in the Crooble and Liverpool Plains districts. Three trials were conducted on SFNB in the varieties Gairdner (Crooble and Spring Ridge) and Fitzroy (Caroona). The remaining trial was conducted on the closely related disease, net form net blotch (NFNB) in the variety Grimmett near Curlewis. All trial sites other than Crooble had been planted into 2007 barley stubble. Crooble was planted to chickpeas in 2007 and wheat in All sites had SFNB or NFNB naturally present before first application timing. Fungicide Program Product Product rate Timing 250 ml/ha T2, T3 and T4 Tilt Single application 500 ml/ha T1, T2, T3 and T4 Prosaro + Hasten 1% 150 ml/ha T3 Multiple 250 ml/ha x 2 T2+T3 and T3+T4 Tilt application 250 ml/ha x 3 T2+T3+T4 T1 = Timing 1, T2 = Timing, T3 = Timing 3, T4 = Timing 4 NB Timing 1 was expected to be too early with only a single treatment evaluated SFNB disease ratings, grain yield and quality were assessed as in Despite generally soft growing conditions in 2008, SFNB in many barley crops failed to develop to concerning levels. No results are presented for the SFNB trial at Spring Ridge. The trial area was affected, firstly by glyphosate drift and then suffered severe crop effects as a result of a post emergent grass herbicide. This herbicide damage produced symptoms similar to SFNB. Variability in visual disease ratings and the general poor growing conditions resulted in extremely uneven and erratic yields. Grower Needs First 6

7 Multi-trial summary Disease levels Due to large site differences in disease levels and treatment performance, no multi trial summaries for disease severity have been presented for 2007 or Disease graphs are located in the individual trial results. Key messages SFNB severity 2007 Disease well established at both sites before T1 T1 application at ~GS30 (jointing) in both trials, T2-14 days later at ~GS31-33, T3 another days later at ~GS39-45 Surprising level of disease suppression from T1 application No clear difference in disease control between individual timings No clear rate response to Tilt observed No clear difference in efficacy evident between Tilt and Amistar Xtra All treatments suppressed SFNB, none fully controlled it Key messages SFNB severity 2008 Disease well established at all sites before T1 T1 application at ~GS14-15/23-26 (expected to be too early for prolonged disease management), T2 at ~GS31, T3 at ~GS32-33, T4 varied between ~GS39-57 Most consistent disease suppression from single applications at Timing 2 and 3 and multiple applications No consistent rate response to Tilt observed No clear difference in efficacy evident between Tilt and Prosaro All treatments suppressed SFNB, none fully controlled it Grower Needs First 7

8 Yield impact Grain yield 2007 mean % of Untreated yield Columns show the mean yield as a % of Untreated. Range bars show the actual results Untreated yield: North Star 1217 kg/ha, Bellata 2969 kg/ha Key messages Yield 2007 No significant difference in yield at either site However all 11 fungicide treatments recorded higher yield than the Untreated at North Star and 10 of 11 fungicide treatments recorded higher yield at Bellata No clear difference in yield between individual application timings No clear difference between multiple application timings or between single and multiple application No clear difference between products or rates applied Key messages Yield 2008 As yield responses varied dramatically by site, no multi trial graph is presented. Actual yield graphs are located in the individual trial results. Grower Needs First 8

9 Quality impact Key messages Screenings 2007 No significant difference in screenings at either site Untreated screenings were 31% at North Star and 34% at Bellata Single application reduced screenings to ~17% at North Star and ~28% at Bellata 20 of 22 treatments reduced screenings across the two sites No clear difference in screenings between individual application timings Multiple applications trended to lower screenings than single applications No clear difference between products or rates applied Key messages Screenings 2008 Significant differences only at Caroona SFNB site Untreated screenings were 4% at Caroona, 23% at Crooble and 7% at Curlewis Single application reduced screenings to ~3% at Caroona, ~19% at Crooble and ~6% at Curlewis 33 of 33 treatments reduced screenings across the three sites No clear difference in screenings between individual application timings Multiple applications trended to lower screenings than single applications No clear difference between products or rates applied Grower Needs First 9

10 Key messages Retention 2007 Retention is a measure of barley grain size. It is the % of grain weight that is retained above a 2.5 mm screen. High % retention is important for malt classification. No significant difference in retention at either site Untreated retention was 32% at North Star and 7% at Bellata Single application increased retention to ~48% at North Star and ~11% at Bellata 21 of 22 treatments increased retention across the two sites No clear difference in retention between individual application timings No clear difference between multiple application timings or between single and multiple application No clear difference between products or rates applied Key messages Retention 2008 Significant differences only at Curlewis NFNB site Untreated retention was 77% at Caroona, 23% at Crooble and 44% at Curlewis Single application increased retention to ~81% at Caroona, ~27% at Crooble and ~53% at Curlewis 32 of 33 treatments increased retention across the three sites No clear difference in retention between individual application timings Multiple applications trended to increased % retention compared to single applications No clear difference between products or rates applied Grower Needs First 10

11 Key messages Test weight 2007 No significant difference in test weight at either site Untreated test weight was 62 kg/hl at North Star and 60 kg/hl at Bellata Single application increased test weight to ~66 kg/hl at North Star and ~61 kg/hl at Bellata 22 of 22 treatments increased test weight across the two sites No clear difference in test weight between individual application timings No clear difference between multiple application timings or between single and multiple application No clear difference between products or rates applied Key messages Test weight 2008 No significant difference in test weight at any site Untreated test weight was 56 kg/hl at Caroona, 58 kg/hl at Crooble and 62 kg/hl at Curlewis No impact on test weight at Caroona or Curlewis, with single application increasing test weight to ~59 kg/hl at Crooble Grower Needs First 11

12 Economic impact Economic impact 2007 net benefit compared to Untreated Assuming Tilt $25/L, foliar application $8/ha, Feed 3 grain price $325/t, Feed 2 $340/t and Feed 1 $355/t Key messages net benefit Trials conducted in a year with very low rainfall after June On 2007 grain prices, mean fungicide treatment benefit was $102/ha No clear difference between application timing, product or Tilt rate Encouraging level of benefit obtained from application at Timing 1 or 2 in both trials Similar net benefit from multiple application but with apparently lower variability in these two trials Net economic benefit 2008 No multi trial summary due to site variability. Comments included in individual trials. Grower Needs First 12

13 Individual trial results 2007 Trial number: Site: Co-operator: NGA0720 Wilby North Star Michael McIntosh Crop stage (GS) SFNB leaf area diseased Timing 1: 02/07/ % on Flag-4 and -5 Timing 2: 17/07/ % on Flag-3 and -4 Timing 3: 09/08/ % on Flag-1 and -2 Rainfall: ~50 mm, 9-11 days after T3 Leaf area affected by SFNB at 56 DAA1/ 41 DAA2/ 18 DAA3 T 250 = Tilt 250 ml, T 500 = Tilt 500 ml, Am 400 = Amistar Xtra 400 ml DAA1 = Days after application Timing 1 etc, variety Skiff Assessment 18 days later revealed very high levels of SFNB in the Untreated (50% of Flag area diseased, 70% of Flag-1, 92% of Flag-2). There was no significant difference in disease level between any fungicide program and the Untreated although all fungicide treatments recorded lower disease levels than the Untreated on Flag-1 and Flag-2. Grower Needs First 13

14 Key messages disease severity All treatments only provided very low levels of suppression of SFNB High levels of infection were still seen even after three applications of Tilt 250 ml or two applications of Tilt 500 ml Disease progress was very rapid after mid August rain event Little apparent difference between application timings, products or product rate Yield impact T 250 = Tilt 250 ml, T 500 = Tilt 500 ml, Am 400 = Amistar Xtra 400 ml Untreated yield 1217 kg/ha, no significant difference between any treatment and Untreated Key messages yield and quality Low yielding, moisture stressed site with high SFNB incidence and severity Clear trend to increased yield from fungicide treatment with little apparent difference between application timings, products or product rate Mean treatment yield benefit 352 kg/ha or 29% (range kg/ha) Mean treatment test weight benefit 4 kg/hl (range 2-5 kg/hl) unpresented Screenings: Untreated 31%, treatment mean 17% (range 12-24%) - unpresented All fungicide treatments eligible for Feed 1 or 2, Untreated only Feed 3 Mean net benefit at 2007 grain price: $113/ha (range $6 to $194/ha) Grower Needs First 14

15 Trial number: Site: Co-operator: NGA0721 Mayfield South Bellata Ian MacCue Crop stage (GS) SFNB leaf area diseased Timing 1: 27/07/ % on Flag-5 and -6 Timing 2: 10/08/ % on Flag-3 and -4 Timing 3: 24/08/ % on Flag-2 and -3 Rainfall: ~39 mm 7-10 days after T2 Leaf area affected by SFNB at 48 DAA1/ 34 DAA2/ 20 DAA3 T 250 = Tilt 250 ml, T 500 = Tilt 500 ml, Am 400 = Amistar Xtra 400 ml DAA1 = Days after application Timing 1 etc, variety Kaputar Key messages disease severity All treatments provided good levels of SFNB suppression in a low disease site Disease progress was rapid after mid August rain event Little apparent difference between application timings or Tilt product rate Grower Needs First 15

16 Amistar Xtra trended to improved disease suppression compared to Tilt Multiple application trended to improved suppression compared to single application Yield impact Untreated yield 2969 kg/ha, no significant difference between any treatment and Untreated Key messages yield and quality Trial under low SFNB severity with crop suffering from a dry and very quick finish Trend to increased yield from fungicide treatment with little apparent difference between application timings, products or product rate Mean treatment yield benefit 221 kg/ha or 7% (range -104 to 407 kg/ha) Test weight: Untreated benefit 1 kg/hl (range 0-2 kg/hl) - unpresented Screenings: Untreated 34%, treatment mean 24% (range 21-37%) - unpresented Five fungicide treatments eligible for Feed 2, Untreated and remaining treatments only Feed 3 Mean net benefit at 2007 grain price: $64/ha (range $-49 to $170/ha) Grower Needs First 16

17 Individual Trial Results 2008 Individual trial results 2008 Trial number: Site: Co-operator: NGA0814 Rossmar Park Caroona Angus Duddy Crop stage (GS) SFNB leaf area diseased Timing 1: 18/08/ / % on 3 rd top leaf Timing 2: 29/08/ % on 3 rd top leaf Timing 3: 18/09/ % on 3 rd top leaf Timing 4: 13/10/ % on Flag-1 and -2 Rainfall: 10 mm T1 to T2, 52 mm T2 to T3, 80 mm T2 to T3 Leaf area affected by SFNB at 72 DAA1/ 61 DAA2/ 41 DAA3/ 16 DAA4 T 250 = Tilt 250 ml, T 500 = Tilt 500 ml, P 150 = Prosaro 150 ml + Hasten 1% DAA1 = Days after application Timing 1 etc. variety Fitzroy Low SFNB severity until ~ Timing 3 but then built up to moderate final levels in October Grower Needs First 17

18 Individual Trial Results 2008 Key messages disease severity Most consistent SFNB suppression came from application at Timing 3 or the multiple application treatments However the most effective treatment only averaged 50-60% SFNB suppression No clear difference between Tilt and Prosaro at Timing 3 No apparent benefit from Timing 1 or 2 application at DAA Non significant dose response trend to Tilt at Timing 3 and 4 Yield impact T 250 = Tilt 250 ml, T 500 = Tilt 500 ml, P 150 = Prosaro 150 ml + Hasten 1% Untreated yield 2830 kg/ha, no significant difference between any treatment and Untreated Key messages yield and quality Trend to reduced yield from Timing 1, 2 or 4 application - unexplained Trend to minor yield benefit (5-7%) from Timing 3 alone or multiple application at T3 & T4 or T2 & T3 & T4. Minor benefits in % screenings and retention recorded by all treatments, however very low test weight (55-57 kg/hl) resulted in Feed 3 quality for all samples No economic benefit from any treatment at $130/t grain price Grower Needs First 18

19 Individual Trial Results 2008 Site: Trial number: Co-operator: NGA0815 Kanimbla Crooble Bill McDonald Crop stage (GS) SFNB leaf area diseased Timing 1: 23/07/ / % on 2 nd and 3 rd top leaf Timing 2: 08/08/ % on 2 nd and 3 rd top leaf Timing 3: 20/08/ % on 2 nd and 3 rd top leaf Timing 4: 11/09/ % on Flag-1 and -2 Rainfall: 27 mm August, 41 mm September Leaf area affected by SFNB at 63 DAA1/ 47 DAA2/ 35 DAA3/ 13 DAA4 T 250 = Tilt 250 ml, T 500 = Tilt 500 ml, P 150 = Prosaro 150 ml + Hasten 1% DAA1 = Days after application Timing 1 etc, variety Gairdner Very low SFNB severity until after Timing 4 which then built up to low final levels in late September Grower Needs First 19

20 Individual Trial Results 2008 Key messages disease severity Most consistent SFNB suppression (60-80%) came from multiple application treatments The most effective single timings were Timing 2 and 3 Timing 4 was poorest of single application timings Timing 1 still resulted in significant SFNB suppression on the top 3 leaves Prosaro at Timing 3 only provided similar SFNB suppression to Tilt 250 ml Yield impact T 250 = Tilt 250 ml, T 500 = Tilt 500 ml, P 150 = Prosaro 150 ml + Hasten 1% Untreated yield 4129 kg/ha, no significant difference between any treatment and Untreated Key messages yield and quality No clear yield response from any treatment under late and low disease pressure Screenings: Untreated 23%, treatment mean 18% (range 14-22%) - unpresented Minor benefits in test weight recorded by all treatments, however very low test weight (58-60 kg/hl) would have resulted in borderline Feed 2 or 3 quality for all samples No consistent economic benefit from fungicide treatment in this situation Grower Needs First 20

21 Net Form Net Blotch Management Individual Trial Results 2008 Trial number: Site: Co-operator: NGA0813 Kalimna Curlewis Ellis Watters Crop stage (GS) NFNB leaf area diseased Timing 1: 14/07/ / % on 2 nd and 3 rd top leaf Timing 2: 30/07/ % on 2 nd and 3 rd top leaf Timing 3: 13/08/ % on 2 nd and 3 rd top leaf Timing 4: 03/09/ % on Flag-1 and -2 Rainfall: 20 mm T1 to T2, 51 mm T3 to T4, 35 mm after T4 Leaf area affected by NFNB at 67 DAA1/ 51 DAA2/ 37 DAA3/ 16 DAA4 T 250 = Tilt 250 ml, T 500 = Tilt 500 ml, P 150 = Prosaro 150 ml + Hasten 1% DAA1 = Days after application Timing 1 etc, variety Grimmett Only low to moderate NFNB severity throughout trial Grower Needs First 21

22 Net Form Net Blotch Management Individual Trial Results 2008 Key messages disease severity Most effective NFNB suppression (~90%) came from three application treatment The most effective single applications were at Timing 2 Timing 1 was the poorest of single applications but still reduced NFNB levels on the top 3 leaves There was no benefit from Prosaro compared to Tilt for NFNB suppression Yield impact T 250 = Tilt 250 ml, T 500 = Tilt 500 ml, P 150 = Prosaro 150 ml + Hasten 1% Untreated yield 3688 kg/ha, no significant difference between any treatment and Untreated Key messages yield and quality Clear trend to increased yield from fungicide treatment, mean 338 kg/ha (range kg/ha) Most consistent apparent benefit from single application was at Timing 2 and 3, multiple application at Timings 3 and 4 or the three application treatment Little benefit evident from Prosaro in either NFNB suppression or yield Screenings: Untreated 7%, treatment mean 5% (range 4-6%) unpresented Retention: Untreated 44%, treatment mean 56% (range 50-62%) unpresented Mean net benefit at $130/t grain price: $24/ha (range $-5 to $50/ha) Grower Needs First 22