Disease Management

Selection of Disease Resistant or Disease Tolerant Varieties

Cereal varieties should be selected with resistance or tolerance to diseases important in your area. Keep in mind that even a moderate level of resistance may be adequate to avoid significant losses to certain diseases. It is particularly important to select varieties with resistance to Fusarium head blight, soilborne viruses, leaf rust, and powdery mildew. Resistance to diseases such as rusts and smuts may be specific against certain pathogen races, so make sure that the variety you select is resistant to all fungus races known to occur in your area.

Seed Treatment

Treating cereal grain seeds with fungicides is sound insurance against a number of diseases that impair stands, reduce yields, and lower grain quality. Certified seed is treated with fungicide(s) by the seed supplier. Certain products are also available for wheat producers to apply as a slurry or seedbox application to nontreated seed. Contact your farm supply dealer for information on specific products. Seed fungicides are essential for control of smut and bunt diseases. Seed fungicides also kill fungi that cause seed decay and seedling blights. Only certain fungicides (mefenoxam and metalaxyl) are strongly active against oomycete pathogens such as Pythium, so seed treatment products often include combinations of fungicides. A few systemic fungicides also have seedling foliar activity that reduces fall rust and mildew infections. Some new seed treatment products include biological ingredients with efficacy against plant parasitic nematodes.

Foliar Fungicides

Foliar and head diseases induced by fungi can reduce the yield of small grains in New York State. Experiments with fungicides in non-maximum-yield situations, however, have sometimes shown reduction in disease with little resulting yield benefit. Fungicides, therefore, should be used as one part of a total management system. Factors such as variety selection, planting date, weed and insect control, and fertility should be optimized before fungicide use is considered. Powdery mildew, leaf rust, and fungal leaf and glume spots are among the diseases most frequently encountered. Because disease occurrence varies between fields and between seasons, fungicides are most effectively used in conjunction with a scouting program. One of the major aims of a foliar fungicide program is to keep the flag leaves free from disease because flag leaf function is important for filling the grain. Early-season diseases can also adversely affect yield, however.

Tables

Table 5.7.1 Efficacy of fungicides for wheat disease control based on appropriate application timing*
FungicidesPowdery mildewStagnospora leaf/glume blotchSeptoria leaf blotchTan spotStripe rustLeaf rustSoybean rustStem rustFusarium head blightHarvest Restriction
ClassActive ingredientProductRate/A (fl oz)
StrobilurinPicoxystrobin 22.5%*§Aproach SC 4,56.0-12GVGVGVGE1VGVGNLFeekes 10.5 
Pyraclostrobin 23.6%Headline SC56.0-9.0GVGVGEE1EGNLFeekes 10.5 
Triazolemetconazole 8.6%Caramba 0.75 SL10.0-17.0VGVGUVGEEEG30 days 
propiconazole 41.8%Tilt 3.6 EC Generics4.0VGVGVGVGVGVGVGPFeekes 10.5 
prothioconazole 19%Proline 480 SC4.3-5.72UVGVGVGVGVGVGG30 days 
prothioconazole 19%
tebuconazole 19%
Prosaro 421 SC36.5-8.2GVGVGVGEEEG30 days 
Mixed modes of action 5tebuconazole 22.6%
trifloxystrobin 22.6%
Absolute 500 SC 35.0GVGVGVGVGVGVGNL35 days 
cypraconazole 7.17%
picoxystrobin 17.94%
*§Aproach Prima SC 4,53.4-6.8VGVGVGVGEVGUNRGrain: 45 days; hay: 21 days 
propiconazole 11.7%
azoxystrobin 7.0%
Avaris 200 SC7.0-14.0VGVGVGVGEEVGNLFeekes 10.5.4 
prothioconazole 16.0%
trifloystrobin 13.7 %
Delaro 325 SC 38.0GVGVGVGVGVGVGNLFeekes 10.5 or 35 days 
pydiflumetofen 13.7%
propiconazole 11.4%
Miravis Ace SE13.7VGVGVGVGVGVGVGGFeekes 10.54 
fluapyroxad 2.8%
pyraclostrobin 18.7%
propiconazole 11.7%
Nexicor EC 4,57.0-13.0GVGEEEEVGNLFeekes 10.5 
fluxapyroxad 14.3% pyraclostrobin 28.6%Priaxor 3,5,74.0-8.0GVGVGEVGVGGNLFeekes 10.5 
azoxystrobin 13.5%
propiconazole 11.7%
Aframe Plus 2.2 SE
Quilt Xcel 2.2 SE
10.5-14.0VGVGVGVGEEVGNLFeekes 10.54 
prothioconazole 10.8% trifloxystrobin 32.3%Stratego YLD 34.0GVGVGVGVGVGVGNLFeekes 10.5 or 3.5 days 
benzovindiflupyr 2.9%
azoxystrobin 10.5%
propiconazole 11.9%
flutriafol 18.63%
azoxystrobin 25.3%
Trivapro 2.21 SE3
TopGuard EQ4
9.4-13.7
4.0-7.0
VG
VG
VG
NL
VG
VG
VG
VG
E
E
E
E
VG
VG
NL
NL
Feekes 10.54
Feekes 10.54; 30 days
 
metconazole 7.4%
pyraclostrobin 12%
TwinLine 1.75 EC 3,57.0-9.0GVGVGEEEVGNLFeekes 10.5 
*Adapted for New York from information developed by the USDA-NIFA Committee on Management of Small Grain Cereal Diseases (NCERA-184). Efficacy ratings for each fungicide listed in the table were determined by field-testing the materials over multiple years and locations by the members of the committee. Efficacy ratings are based upon level of disease control achieved by product, and are not necessarily reflective of yield increases obtained from product application. Efficacy depends upon proper application timing, rate, and application method to achieve optimum effectiveness of the fungicide as determined by labeled instructions and overall level of disease in the field at the time of applications. Difference in efficacy among fungicide products were determined by direct comparisons among products in field tests and are based on a single application of the labeled rate as listed in the table. Table includes systemic fungicides available that have been tested over multiple years and locations. This table is not intended to be a list of all labeled products. This information is provided only as a guide. It is the responsibility of the pesticide applicator by law to read and follow all current label directions. No endorsement is intended for products listed, nor is criticism meant for products not listed. Members or participants in the NCERS-184 committee assume no liability resulting from the use of these products. Efficacy categories: NR=Not Recommended; P=Poor; F=Fair; G=Good; VG=Very Good; E=Excellent; NL=Not Labeled for use against this disease; U=Unknown.
1 Efficacy may be significantly reduced if solo strobilurin products are applied after stripe rust infection has occurred.
2 Rates of 5.0 to 5.7 fl oz are labeled only for applications at flowering to suppress Fusarium head blight; Lower rates of 4.3-5.0 fl oz are labeled for applications to control foliar and stem diseases.
3Aerial application is not allowed in New York.
4 This product is not for sale, distribution, or application in Nassau or Suffolk Counties.
5Aerial application of this product is not allowed within 100 feet of aquatic habitats.
6Application of this product is not allowed within 100 feet of coastal marsh.
7Labeled for suppression of eyespot (Tapesia) with 6-8 fl oz.
Table 5.7.2. Scouting-based criteria for deciding on foliar fungicide applications to winter wheat.
Wheat StageWhenScouting ObservationsDecision 
Stem elongationearly MayAdequate stand, vigorous plants(NO)
(YES)
Discontinue monitoring
Continue monitoring
Before flag leaf emergencemid-MayDisease on any of top three leaves of at least 50% of main tillers(NO)
(YES)
Don’t spray now; continue monitoring
Spray with efficacious fungicide from Table 5.7.1; continue monitoring
Head emergencelate MayDisease on either of top two leaves of at least 50% of main tillers; forecast of wet weather in next week(NO)
(YES)
Don’t spray
Spray only with efficacious triazole or triazole & SDHI product
Initiation of floweringlate May to early JuneAdequate stand, vigorous plants(NO)
(YES)
Don’t spray
Spray only with efficacious triazole or triazole & SDHI product
Table 5.7.3. Influence of grain price and yield on the relative profit of a single foliar fungicide application.1
 Yield Increase(Bu/A)
Wheat Price ($/Bu)051015
 Relative Profit ($/A)
3.00-30-15015
3.50-30-12.5522.5
4.00-30-101030
4.50-30-7.51537.5
5.00-30-52045
5.50-30-2.52552.5
6.00-3003060
6.50-302.553567.5
1Assumes additional input of $30 per acre based on costs of fungicides and application. Actual costs can be expected to vary.
Table 5.7.4. Fungicides registered for control of important barley diseases in New Yorka
Fungicide(s)Powdery mildewStagonospora blotchNet blotchSpot blotchScaldRusts (Puccinia spp.)Fusarium head blight1Harvest restriction
ClassActive ingredientProductRate/A (fl. oz)
Strobilurinpicoxystrobin 22.5%*†Aproach SC36.0 - 12XXXXXXNLFeekes 10.5
fluoxystrobin 40.3%*†Evito 480 SC42.0-4.0XXXXXXNLFeekes 10.5
pyraclostrobin 23.6%Headline SC36.0-9.0XXXXXXNLFeekes 10.3
Triazolemetconazole 8.6%Caramba 0.75 SL10.0-17.0
(13.5-17.0 for FHB)
XXXXXXX Good30 days
propiconazole 41.8%Tilt 3.6 EC Generics4.0XXXXXXX PoorFeekes 10.5.4
prothioconazole 41%Proline 480 SC2.8-4.3
(5-5.7 for FHB2)
XNLXXXXX Good32 days
prothioconazole 19%
tebuconazole 19%
Prosaro 421 SC26.5-8.2XNLXXXXX Good30 days
Mixed modes of actiontebuconazole 22.6%
trifloxystrobin 22.6%
Absolute 500 SC23.3XXXXXXNL40 days
propiconazole 11.7%
azoxystrobin 7.0%
Avaris 200 SC7.0-14.0XXXXXXNLFeekes 10.5.4
prothioconazole 16.0%
trifloystrobin13.7%
Delaro 325 SC28.0XXXXXXNLFeekes 8 or 40 days
pydiflumetofen 13.7%
propiconazole 11.4%
*Miravis Ace SE13.7XXXXXNLX GoodFeekes 10.5.4
Mixed modes of actionfluapyroxad 2.8%
pyraclostrobin 18.7%
propiconazole 11.7%
*†Nexicor EC27.0-13.0XXXXXXNLFeekes 10.3
fluxapyroxad 14.3%
pyraclostrobin 28.6 %
*†Priaxor34.0 – 8.0XXXXXXNLFeekes 10.3
propiconazole 11.7%
azoxystrobin 13.5%
Quilt Xcel 2.2 SE
Aframe Plus 2.2 SE
10.5-14.0XXXXXXNLFeekes 10.5.4
prothioconazole 10.8%
trifloxystrobin 32.3%
Stratego YLD22.3XXXXXXNLFeekes 8 (flag leaf ligule emergence) or 30 days
benzovindiflupyr 2.9%
azoxystrobin 10.5%
propiconazole 11.9%
*Trivapro 2.21 SE29.4-13.7XXNLXNLXNLFeekes 10.5.4
metconazole 7.4%
pyraclostrobin 12%
TwinLine 1.75 EC37.0-9.0XXXXXXNLFeekes 10.5
a This information is provided as a guide for the convenience of barley producers in New York. Registrations are granted and withdrawn and labels are changed continuously. No endorsement is intended for products listed, nor is criticism meant for products not listed. It is the responsibility of the pesticide applicator by law to read and follow all current label directions and restrictions. An X indicates that control of a disease is included on the product label whereas NL indicates it is not a labeled use.
* Restricted-use pesticide
† Not for sale or use in Nassau and Suffolk Counties.
1 Statements of relative efficacy for suppression of Fusarium head blight severity and reduction of contamination of grain by the mycotoxin, deoxynivalenol, are based on consensus research observations by members of the USDA-NIFA Committee on Management of Small Grain Cereals (NCERA-184); members of NCERA-184 assume no liability resulting from use of these products.
2Aerial application not allowed in New York.
3Aerial application not allowed within 100 feet of aquatic habitats.
4Application of this product is not allowed within 100 feet of coastal marsh.