Leaf Rust in Barley 2011 Background, Aims and Method

Transcription

1 Lef Rust in Brley 211 Bckground, Aims nd Method Bckground Lef rust in rley (Puccini hordei) occurred t epidemic levels in 21 cross mny res of northern NSW nd southern Qld. This epidemic ws driven y comintion of: 1. Widespred susceptile host Grout ws dominnt vriety rted s very susceptile (VS) to lef rust 2. Lrge mounts of disese inoculum lef rust ws widespred in rley in the region the previous seson 3. Fvourle conditions for disese development 21 ws seson with ove verge to record levels of rinfll during August nd Septemer comined with record high minimum tempertures during Septemer Commercil experience from 21 indicted tht fungicides such s Tilt or Folicur (oth registered in rley ut without clims for lef rust control) provided very poor efficcy ginst this disese. Aims 1. To screen the rnge of currently ville fungicides for efficcy ginst lef rust in rley 2. To compre lef rust control etween single nd multiple pplictions 3. To quntify the overll level of yield, grin qulity nd economic cost 4. To improve our understnding of lef rust mngement in rley

2 Lef Rust in Brley 211 Bckground, Aims nd Method Method A progrm of six trils ws plnned in commercil rley crops from Gunnedh in the south to the Drling Downs. Five sites were selected in pddocks of Grout, the most susceptile vriety with rting of VS (very susceptile) with the sixth site in pddock of Commnder, rted S (susceptile). Lef rust did not develop, even in the vriety Grout, t either of the Gunnedh sites. Consequently these trils were not spryed. The sites t Mclister nd Allor, Qld nd North Str nd Yllroi, NSW were spryed when lef rust ws first detected in either the surrounding commercil crop or the pegged out tril re. Tretments Tretment Numer Product Rte (ml/h) Adjuvnt Appliction Timing Approximte product cost $/h 1 Untreted Trizole Pro High lel rte - 1 $6.5 3 Tilt Xtr 25-1 $9. 4 Tilt Xtr 25 Bonz.5% 1 $9. 5 Tilt Xtr 5-1 $18. 6 Tilt Xtr x & 2 $18. 7 Trizole Te High lel rte - 1 $4.5 8 Opus 5-1 $16. 9 Amistr Xtr 2 Adigor 2% 1 $1.5 1 Amistr Xtr 4 Adigor 2% 1 $ Oper 5-1 $ Prosro 3-1 $18. Tretments 2 nd 7 re common fungicides, registered for use in rley ut without lef rust control clim. These were included for enchmrking purposes. Appliction Timings Timing 1 = first sign of lef rust Timing 2 = ~21 dys fter timing 1 (two pplictions of Tilt Xtr 25 ml were pplied in Trt 6) Assessments The four spryed trils were ssessed for % lef re disesed due to either lef rust, or spot form net lotch (SFNB), on the top 2-3 leves. The trils t Mclister nd Allor on the Drling Downs oth developed moderte levels of lef rust with no SFNB present. The tril ner Yllroi developed low levels of oth lef rust nd SFNB. The tril ner North Str developed only low levels of SFNB, despite lef rust presence in the surrounding commercil crop. All sites were hrvested using smll plot heders with grin qulity lso ssessed.

3 Lef Rust in Brley 211 Results in Nutshell Results in Nutshell Disese level comments Despite the mjority of sites eing in pddocks of Grout (rted VS for lef rust), only moderte levels of lef rust developed in the two Qld trils nd very low levels t Yllroi Lef rust ppered to develop much more slowly thn in 21 nd did not increse rpidly until lte Septemer/erly Octoer Lef rust control It ppered tht the Timing 1 pplictions, mde on the first sign of lef rust, were up to month erlier thn when lef rust ecme most ctive The most effective control ws otined from two pplictions of fungicide (Tilt Xtr 25 ml) with the second timing much closer to the strt of more ctive disese development Amistr Xtr 4 ml provided the est efficcy from single ppliction At the highest disese pressure site, ll fungicides reduced lef rust levels y ~45-65% even when pplied t lest 4 weeks prior to rpid disese development Fungicides with lef rust clims provided more consistent lef rust suppression thn Trizole Te nd Trizole Pro, oth registered for use in rley, ut without lef rust lel clim Yield There ws no significnt difference in yield in ny of the trils At the highest disese pressure site (Mclister) there ws trend to yield enefit from ll fungicide tretments (men 9%, rnge 6-17%) Grin qulity Grin size ws significntly reduced t the highest disese site. Grin from the Untreted plots ws significntly lower in % retention nd higher in % screenings thn 8 of the 11 fungicide tretments. The mjor question - why ws lef rust much igger issue in 21? The concern fter 21 ws tht once lef rust ecme well estlished it ws nerly impossile to mnge. As result, the pproch tken in 211 ws to spry t first sign of lef rust presence in very susceptile or susceptile vriety.

4 1st Sep 3rd 5th 7th 9th 11th 13th 15th 17th 19th 21st 23rd 25th 27th 29th Diurnl Men Temperture o C Lef Rust in Brley 211 Results in Nutshell However despite hving very susceptile host nd the presence of inoculum in the crop, lef rust ws only minor disese issue in 211. Disese epidemics rely on hving susceptile host, plentiful inoculum nd conducive conditions for disese development. Susceptile host: the mjority of trils in 211 were in pddocks of Grout with the disese ctully present in the surrounding crop. Plentiful inoculum: very hrd to quntify ut ove verge rinfll ws recorded in summer 21/11. This should hve provided mple opportunity for volunteer rley plnts nd the oversummering of lef rust inoculum. In ddition lef rust inoculum ws present t most sites. Conducive conditions: ppers tht the conditions in Septemer 21 were much more suitle for lef rust development thn in 211 with the two most likely fctors eing rinfll nd temperture. Rinfll in mny res of southern Qld ws t record highs in 21 nd certinly much closer to verge in 211. However in northern NSW rinfll ws well ove verge during oth yers. Interntionl literture indictes tht for rpid disese development, lef rust requires tempertures ~6 o C wrmer thn for stripe rust in whet. Diurnl mens (dily verge of mximum nd minimum) of ~16-22 o C re often cited s idel for lef rust development with stripe rust preferring ~1-16 o C. Men minimum monthly tempertures were t record highs in mny prts of northern NSW nd southern Qld in Septemer 21. At Dly in Septemer 21, the men minimum temperture ws 12. o C compred to 6.9 o C in 211 nd long term men of 8.8 o C. In the first hlf of Septemer 21 the men minimum ws 11.4 o C compred to only 5.6 o C in 211. The grph elow shows the diurnl men tempertures t Dly in Septemer 21 nd 211. The shded rectngle indictes the idel temperture conditions for lef rust development Diurnl Men Tempertures (Dly Sept 21 nd 211)

5 Lef Rust in Brley 211 Results in Nutshell Low minimum tempertures my explin why lef rust hs only infrequently een mjor issue of rley in the north. In verge sesons, rley is lredy strting to mture or even senesce just s tempertures ecome more fvourle for rpid disese development. In contrst, in 21 lef rust strted to develop rpidly from erly Septemer comined with lter mturing nd high yielding crops driven y the record spring rinfll. Overll: 1. All fungicides provided useful levels of lef rust suppression, even when rpid disese development did not occur until ~3-5 weeks fter ppliction 2. Crops should e monitored for the presence of lef rust nd fungicides pplied in the erly stges of epidemic development 3. Lef rust mngement strtegies should focus on; selecting rley vrieties with incresed resistnce, reducing the green-ridge (rusts need live plnts to over-summer) nd the use of fungicides s erly s possile during ctive disese development 4. Lef rust in rley is likely to e igger thret in yers with ove verge diurnl men tempertures in spring, prticulrly when comined with lte mturing crops nd good moisture vilility Acknowledgment: Thnks to Greg Pltz (Principl Pthologist, DAFF Qld) for report review nd suggestions Vrieties displying this symol eside them re protected under the Plnt Breeders Rights Act 1994 Registered trdemrk

6 % lef re disesed (SFNB) Lef Rust in Brley 211 Tril: Loction: RH1114 Grigue, ~15 km south west of North Str, NSW Plnting dte: 22/5/211 Plot size: Tril design: Spry prmeters: 12 x 4m on 33cm row spcings Rndomised complete lock with four replictes AIXR1115 t 7 L/h (3 kp nd 1.3 km/hr) Vriety: Grout Crop stge Lef rust level SFNB Spry timing 1: 24/8/211 ~GS49 (wns visile) Nil Present Spry timing 2: 15/9/211 ~GS59-65 (heds fully emerged) Nil Present Lef rust comments: At Timing 1, lef rust could e found in the commercil pddock ut ws not detected in the tril re. There ws still no lef rust pprent on the 5 th of Septemer with disese levels lso unchnged in the commercil pddock. No lef rust ws found in this tril t ny ssessment. Spot form net lotch (Pyrenophor teres f sp mcult) ws the only disese found in this tril. The grph elow shows the level of SFNB disesed lef re on the 2 th of Septemer (27DAT1, 5DAT2) Flg Flg-1 Flg-2 cde c c cde cde cd e cde cde de Letters of comprison re for the men of the top 3 leves, p=.5.tretments shring the sme letter re not significntly different Key messges SFNB disese severity: SFNB levels were very low with significnt suppression from ll fungicides Amistr Xtr 2 ml nd Prosro 3 ml provided the most effective suppression of SFNB with lowest levels of ctivity from the unregistered Trizole Te t the high lel rte

7 Yield kg/h Lef Rust in Brley 211 Yield: 6, 5, 4, 3, 2, 1, NSD Hrvested 24 th of Octoer, cv 6% Grin qulity: Grin nlysis showed no significnt difference in test weight, protein, retention or screenings. Men test weight 65 kg/hl, men protein 9%, men retention 97%, screenings <1% Key messges yield nd grin qulity: There ws no significnt impct from ny fungicide tretment on yield There ws no significnt impct from ny fungicide tretment on grin qulity Conclusion: No lef rust dt ws generted in this tril despite low level eing pprent in the surrounding commercil pddock in lte August nd the VS (very susceptile) rting of the vriety Grout. Disese control dt ws generted on SFNB with the est performnce from Amistr Xtr 2 ml nd Prosro. Trizole Te does not hve SFNB lel clim nd t the high lel rte it ws the wekest fungicide on this disese. Considering the very low disese pressure, it ws not surprising tht there ws no impct on yield or grin qulity from ny fungicide. Acknowledgments: Thnks to Doug Mkim (tril co-opertor) nd Rchel Norton (NGA) for field ctivity

8 % lef re disesed (Lef rust) Lef Rust in Brley 211 Tril: Loction: RH1116 Gunnmtt, ~5 km est of Yllroi Hll, NSW Plnting dte: 18/5/211 Plot size: Tril design: Spry prmeters: 12 x 4m on 33cm row spcings Rndomised complete lock with four replictes AIXR1115 t 7 L/h (3 kp nd 1.3 km/hr) Vriety: Grout Crop stge Lef rust level SFNB Spry timing 1: 24/8/211 ~GS49 (wns visile) Nil Present Spry timing 2: 15/9/211 ~GS59-65 (heds fully emerged) <1% Present Lef rust comments: At Timing 1, lef rust could e found in the commercil pddock ut ws not detected in the tril re. Lef rust ws found in the Untreted t trce levels on the 5 th of Septemer. Disese levels incresed most rpidly in the Untreted t the end of Septemer with levels on Flg-1 incresing from ~1% on the 21 st of Septemer to ~2.7% on the 4 th of Octoer. The grph elow shows the level of lef rust disesed lef re on the 4 th of Octoer (41DAT1, 19DAT2). 5 Flg Flg Letters of comprison re for the men of the top 2 leves on the 4 th of Octoer, p=.5. Tretments shring the sme letter re not significntly different Key messges lef rust disese severity: Disese levels were very low nd slow to develop with good suppression from ll fungicides Timing 1 pplictions were mde ~3 weeks prior to more rpid disese uild-up The most effective tretment ws two pplictions of Tilt Xtr 25 ml with the second ppliction during the erly stges of disese uild-up

9 Yield kg/h % lef re disesed (SFNB) Lef Rust in Brley 211 Spot form net lotch (Pyrenophor teres f sp mcult) ws lso found t very low levels. The grph elow shows the level of SFNB disesed lef re on the 4 th of Octoer (41DAT1, 19DAT2). 5 Flg Flg Letters of comprison re for men of the top 2 leves, p=.5. Tretments shring the sme letter re not significntly different Key messges SFNB disese severity: SFNB levels very low with significnt suppression from ll fungicides All fungicides provided similr SFNB suppression on Flg-1 on the 4 th of Octoer Trizole Te t the high lel rte resulted in significntly poorer suppression of SFNB thn other fungicides on Flg-2 on the 21 st of Septemer (dt not presented) Yield: 8, 6, 4, 2, NSD Hrvested 24 th of Octoer, cv 12%

10 Lef Rust in Brley 211 Grin qulity: Grin nlysis showed no significnt difference in test weight, protein, retention or screenings. Men test weight 65 kg/hl, men protein 11%, men retention 92%, screenings 2% Key messges yield nd grin qulity: There ws no significnt impct from ny fungicide tretment on yield There ws no significnt impct from ny fungicide tretment on grin qulity Conclusion: Very low levels of lef rust occurred in this tril despite presence in the surrounding commercil pddock in lte August nd the VS rting of the vriety Grout. All fungicides provided useful suppression of oth lef rust nd SFNB under low disese pressure. The unregistered Trizole Te t the high lel rte ws the poorest fungicide on oth diseses t 28DAT1 on Flg-2. Considering the very low disese pressure, it ws not surprising tht there ws no impct on yield or grin qulity from ny fungicide. Acknowledgments: Thnks to Hmish Bckus ( tril co-opertor) nd Rchel Norton (NGA) for field ctivity

11 % lef re disesed (Lef rust) Lef Rust in Brley 211 Tril: Loction: RD1116 Peter s Frms, ~18 km west of Allor, Qld Plnting dte: 8/6/211 Plot size: Tril design: Spry prmeters: 1 x 4m on 25cm row spcings Rndomised complete lock with four replictes AIXR1115 t 7 L/h (3 kp nd 1.1 km/hr) Vriety: Commnder Crop stge Lef rust level Spry timing 1: 26/8/211 ~GS43 (erly oot) Trce Spry timing 2: 6/9/211 ~GS51 (erly hed emergence) Trce Lef rust comments: At Timing 1, lef rust ws found t trce levels only. There ws little progression of lef rust etween the two spry ppliction timings with levels < 1% on Flg-2 t timing 2. The grph elow shows the level of lef rust disesed lef re on the 3 rd of Octoer (38DAT1, 27DAT2). 2 Flg Flg-1 Flg c cde cd e cde cde de cd cd Letters of comprison re for the men of the top 3 leves, p=.5. Tretments shring the sme letter re not significntly different Key messges lef rust disese severity: Disese levels were low to moderte with significnt suppression from ll fungicides Timing 1 pplictions were mde ~2-3 weeks prior to more rpid disese uild-up Tilt Xtr 25 ml x 2 pplictions nd Amistr Xtr 4 ml provided the most effective lef rust control Trizole Te nd Trizole Pro (oth t the high lel rte) provided significntly lower levels of lef rust suppression thn ll fungicides other thn Tilt Xtr 25 ml

12 Yield kg/h Lef Rust in Brley 211 Yield: 4, 3, 2, 1, NSD Hrvested 1 th Novemer, cv 12% Grin qulity: Grin nlysis showed no significnt differences in test weight, protein, retention or screenings. Men test weight 6 kg/hl, men protein 1%, men retention 98%, screenings <2% Key messges yield nd grin qulity: There ws no significnt impct from ny fungicide tretment on yield There ws no significnt impct from ny fungicide tretment on grin qulity Conclusion: Cler differences were pprent etween fungicides in efficcy on lef rust. The most effective control ws chieved y two pplictions of Tilt Xtr 25 ml, 11 dys prt with the most effective single ppliction Amistr Xtr 4 ml. Lef rust t this site developed slowly during lte August nd erly Septemer ut ws widespred y erly Octoer. The sence of significnt yield enefit ws disppointing, however this site ws poorly mnged for wild ots. It is expected tht wild ots hd more impct on yield in this tril thn lef rust. Acknowledgments: Thnks to Shne Peters (tril co-opertor) nd Ro Duncn (NGA) for field ctivity

13 % lef re diseed (Lef rust) Lef Rust in Brley 211 Tril: Loction: RD1117 Wrong, ~3 km north est of Mclister, Qld Plnting dte: 9/6/211 Plot size: Tril design: Spry prmeters: 12 x 4m on 25cm row spcings Rndomised complete lock with four replictes AIXR1115 t 7 L/h (3 kp nd 1.1 km/hr) Vriety: Grout Crop stge Lef rust level Spry timing 1: 6/8/211 ~GS31 (first node) Trce Spry timing 2: 24/8/211 ~GS44-49 (mid oot to wn peep) Nil Lef rust comments: At Timing 1, lef rust ws found t trce levels only with no lef rust pprent t timing 2. Lef rust levels incresed most rpidly in the Untreted t the end of Septemer with levels on Flg-2 incresing from ~5% on the 23 rd of Septemer to ~18% on the 4 th of Octoer. The grph elow shows the level of lef rust disesed lef re on the 4 th of Octoer (59DAT1, 41DAT2). 2 Flg Flg-1 Flg c c Letters of comprison re for the men of the top 3 leves, p=.5. Tretments shring the sme letter re not significntly different Key messges lef rust disese severity: Disese levels were moderte with significnt levels of suppression from ll fungicides It would pper tht timing 1 pplictions were mde t lest 4 weeks prior to ctive disese development with most rpid lef rust uild-up from ~mid-septemer onwrds Two fungicide pplictions of Tilt Xtr 25 ml provided the highest level of control with the second ppliction still ~1-2 weeks prior to ctive disese development

14 % retention Yield kg/h Lef Rust in Brley 211 Amistr Xtr trended to provide the est control from single ppliction t timing 1 nd resulted in ~65% suppression on the top 3 leves Yield: 6, 5, 4, 3, 2, 1, NSD Hrvested 4 th Novemer, cv 6% Grin qulity: Grin nlysis showed no significnt difference in test weight (men 61 kg/hl) or protein (men 11%). However there were significnt differences in retention nd screening. Untreted retention ws ~87% nd significntly lower thn 9 of the 11 fungicide tretments. Untreted screenings were ~4% nd significntly higher thn 8 of the 11 fungicide tretments. The grph elow shows the tretment impct on % retention. 1 9 c c c

15 % screenings Lef Rust in Brley 211 The grph elow shows the tretment impct on % screenings de cde cd e c cd cde cde cde cde 1 Key messges yield nd grin qulity: There ws no significnt impct from ny fungicide tretment on yield. However the men yield of ll fungicide tretments ws 9% higher thn the Untreted with rnge from 6-17% higher. There were significnt differences in oth retention nd screenings. Tilt Xtr 25 ml (timing 1 only) nd Trizole Te provided the lest enefit nd were not significntly different from the Untreted for either ssessment. Conclusion: This tril ws spryed on first sign of lef rust ut under conditions where the disese did not develop rpidly until t lest 4 weeks lter. Under tht sitution, the performnce from ll single ppliction fungicide tretments in providing ~45-65% lef rust suppression ws encourging. The stndout disese control ws chieved from two pplictions of Tilt Xtr 25 ml with the second ppliction still pplied ~1-2 weeks efore ctive disese development. Of the single ppliction tretments, Amistr Xtr 4 ml provided the highest level of lef rust suppression (~65%) on the top 3 leves, more thn 8 weeks fter ppliction. This tril design unfortuntely did not include timing 2 ppliction lone. It is expected tht single fungicide ppliction t this timing lone would hve provided high level of control. Acknowledgments: Thnks to Json Schelerg (tril co-opertor) nd Ro Duncn (NGA) for field ctivity