Wheat Fungicide Selection and Timing Rolling with the Season and Variety. Dr. Madeleine Smith

Transcription

1 Wheat Fungicide Selection and Timing Rolling with the Season and Variety Dr. Madeleine Smith

2 Talk Outline Introduction Considerations before Planting Considerations in Season Take home messages

3 Introduction There are a huge number of factors which can influence the selection of fungicide and the timing of application Balancing these successfully directly influences the level of disease control you achieve

4 Factors Varietal selection Disease Present Growth Stage Weather-risk Application method Chemistry Labelling cost

5 PRE-PLANTING DECISIONS

6 Field History

7 Often over-looked Has their been a particular disease problem in previous years? What was the previous crop and residue? Field History

8 Varietal Selection

9 Varietal Selection Varietal selections are made based on many factors Yield Protein Seed availability and cost Other agronomic traits Disease resistance

10 Varietal Selection Correct varietal selection for your conditions can help minimize inputs and maximize control Consult variety trials bulletins in your state for the latest varietal information on disease resistance U of M Spring wheat- (meas.umn.edu) NDSU-

11 Varietal Selection Rating scales generally done on a 0-9 scale 1 = most resistant 9 = most susceptible

12 Varietal Selection You will also see categories, S, MS, MR, R. As a rough guide: S= Susceptible (7-9) MS= moderately susceptible (5-6) MR= moderately resistant (3-4) R= Resistant (1-2)

13 Varietal Selection-Leaf Rust Variety Rating Bolles 1 Elgin-ND 2 Forefront 2 Knudsen 2 LCS Albany 2 Norden 2 Prevail 2 SY-Soren 2 Focus 3 LCS Breakaway 3 WB-Mayville 3

14 Varietal Selection-BLS Variety Rating SY-Rowyn 2 Prevail 2 Focus 3 Forefront 3 LCS Breakaway 3 SY Ingmar 3

15 Variety Forefront 3 Glenn 3 Rollag 3 Bolles 4 Faller 4 LCS Albany 4 LCS Iguacu 4 Norden 4 Prevail 4 RB07 4 SY Rowyn 4 Varietal Selection-FHB Rating

16 Seed Treatments

17 Should you use them? yes IF: You are planting scabby seed Your are planting seed that may be infected with loose smut You have a history of problems with root and crown rots in a field Seed Treatments

18 IN-SEASON

19 Scouting

20 For wheat diseases, scouting is integral to achieving the best control Scouting Know what diseases are in your fields Spot them early Track their progression

21 Scouting When scouting walk in to the field, make sure you are past the headland Walk a large W pattern Examine plants at each point in the W Look at: severity-what % of leaf is covered by disease Incidence-how many plants have the disease Where is the disease in the canopy? Growth stage of crop

22 Disease Identification

23 Disease Identification Disease guides available at U of M booth and from MN Association of Wheat Growers U of M Extension Website currently being redone

24 Polycyclic vs. Monocyclic Diseases

25 Polycyclic vs. Monocyclic Diseases Monocyclic one round of reproduction e.g. FHB Polycyclic- multiple rounds of reproduction and infection e.g. rusts, tan spot Knowing growth stage, risk of disease development important for polycyclic diseases

26 Growth Staging

27 Growth Staging It is important to know what growth stage the majority of the field is at, this helps us know whether we need to spray given the relative advancement of the disease

28 Growth Staging Feekes-most commonly used Zadocks much more detailed than other GS systems Haun- tiller and grain development not described

29 Assessment of Risk

30 Assessment of Risk If you don t have disease in your field, but there is in your area, what is the risk that you will also get the disease and to spray? Depends on : Weather Growth stage

31 Risk Forecasting Tools General diseases: FHB

32 Before next season, sign up for scab alerts by and text message:

33 Fungicide Selection

34 Fungicide Selection Not all fungicides control diseases equally well The active ingredients make a difference!

35 Strobilurin Triazole Fungicide Selection- NCERA 184 table Fungicide(s) Class Active ingredient Product Picoxystrobin Aproach 22.5% SC Fluoxastrobin Evito % SC Pyraclostrobin Headline 23.6% SC Metconazole Caramba 8.6% 0.75 SL Propiconazole Tilt % EC 4 Prothioconazole Proline 41% 480 SC Tebuconazole Folicur 38.7% 3.6 F 4 Prothioconazole1 9% Prosaro Tebuconazole 421 SC 19% Mixed modes of action 5 Metconazole 7.4% Pyraclostrobin 12% Fluxapyroxad 14.3% Pyraclostrobin 28.6% Propiconazole 11.7% Azoxystrobin 13.5% Prothioconazole 10.8% Trifloxystrobin 32.3% Cyproconazole 7.17% Picoxystrobin 17.94% TwinLine 1.75 EC Rate/A (fl. oz) Powdery mildew Stagonosp ora leaf/glume blotch Septoria leaf blotch Tan spot Stripe rust Leaf rust Stem rust Head scab Harvest Restriction G 1 -- VG 2 VG E 3 VG VG NL Feekes G VG -- VG -- NL Feekes 10.5 and 40 days G VG 2 VG 2 E E 3 E G NL Feekes VG VG -- VG E E E G 30 days 4.0 VG VG VG VG VG VG VG P Feekes VG VG VG VG VG VG G 30 days 4.0 NL NL NL NL E E E F 30 days G VG VG VG E E E G 30 days G VG VG E E E VG NL Feekes 10.5 Priaxor G VG VG E VG VG G NL Feekes 10.5 Quilt Xcel 2.2 SE 4 Stratego YLD Aproach Prima SC VG VG VG VG E E VG NL Feekes G VG VG VG VG VG VG NL Feekes days VG -- VG VG E VG -- NR 45 days

36 Fungicide Timing Where is the disease in the canopy? What is the growth stage? Is the disease polycyclic? What is my risk of disease development?

37 Fungicide Timing Early Season: Scout. If no disease present, DON T spray Why- fungicide resistance, not as good insurance as you think! If there is disease, consider options..

38 Fungicide Timing Early Season Save big guns (Prosaro, Caramba) for later in the season for FHB Propiconazole (Tilt) is good for most diseases at this stage Half rates used- at 3-5 leaf,amount of biomass is lower so effectively A.I. for amount of tissue is the same

39 Fungicide Timing Later season leaf disease, can treat if flag leaf looks to be at risk Watch total applications of A.I. in a season- check labels!

40 Labelling Restrictions ALWAYS read the labeling restrictions for the fungicide you are going to use For up to date information on labeling to: Labels should have any state exemptions, but you can search the MDA website for licensing

41 Fungicide Timing-FHB Early flowering Feekes % of tillers flowering Can push to 5-7 post anthesis Fungicides applied at this time will take care of late season leaf disease

42 FHB- Management Best management practice = resistant variety + fungicide Fungicides: High risk year = Caramba or Prosaro Low risk year = Tebuconazole

43 Take Home Messages Good disease management starts-pre season Varietal selection Seed treatments Field history

44 Take Home Messages Scout early and as often as you can! Use risk forecasting tools to help decision making Select the most appropriate fungicide for the disease(s) present Always follow labelling-application volumes, rates, seasonal max s

45 Take Home Messages Remember some diseases are polycyclic- Tan spot, Rusts-higher risk Disease such as FHB require very specific application methods, timing and chemistry Don t provide additional selection pressure for fungicide resistance

46 Questions? Please contact me at: