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.

Table 5.7.1

Table 5.7.1 Efficacy of fungicides for wheat disease control based on appropriate application timing*
Fungicides Powdery mildew Stagnospora leaf/glume blotch Septoria leaf blotch Tan spot Stripe rust Leaf rust Soybean rust Stem rust Fusarium head blight Harvest Restriction
Class Active ingredient Product Rate/A (fl oz)
Strobilurin Picoxystrobin 22.5% *§Aproach SC 4,5 6.0-12 G VG VG VG E1 VG VG NL Feekes 10.5
Pyraclostrobin 23.6% Headline SC5 6.0-9.0 G VG VG E E1 E G NL Feekes 10.5
Triazole metconazole 8.6% Caramba 0.75 SL 10.0-17.0 VG VG U VG E E E G 30 days
propiconazole 41.8% Tilt 3.6 EC Generics 4.0 VG VG VG VG VG VG VG P Feekes 10.5
prothioconazole 19% Proline 480 SC 4.3-5.72 U VG VG VG VG VG VG G 30 days
prothioconazole 19%
tebuconazole 19%
Prosaro 421 SC3 6.5-8.2 G VG VG VG E E E G 30 days
Mixed modes of action 5 tebuconazole 22.6%
trifloxystrobin 22.6%
Absolute 500 SC 3 5.0 G VG VG VG VG VG VG NL 35 days
cypraconazole 7.17%
picoxystrobin 17.94%
*§Aproach Prima SC 4,5 3.4-6.8 VG VG VG VG E VG U NR Grain: 45 days; hay: 21 days
propiconazole 11.7%
azoxystrobin 7.0%
Avaris 200 SC 7.0-14.0 VG VG VG VG E E VG NL Feekes 10.5.4
prothioconazole 16.0%
trifloystrobin 13.7 %
Delaro 325 SC 3 8.0 G VG VG VG VG VG VG NL Feekes 10.5 or 35 days
pydiflumetofen 13.7%
propiconazole 11.4%
Miravis Ace SE 13.7 VG VG VG VG VG VG VG G Feekes 10.54
fluapyroxad 2.8%
pyraclostrobin 18.7%
propiconazole 11.7%
Nexicor EC 4,5 7.0-13.0 G VG E E E E VG NL Feekes 10.5
fluxapyroxad 14.3% pyraclostrobin 28.6% Priaxor 3,5,7 4.0-8.0 G VG VG E VG VG G NL Feekes 10.5
azoxystrobin 13.5%
propiconazole 11.7%
Aframe Plus 2.2 SE
Quilt Xcel 2.2 SE
10.5-14.0 VG VG VG VG E E VG NL Feekes 10.54
prothioconazole 10.8% trifloxystrobin 32.3% Stratego YLD 3 4.0 G VG VG VG VG VG VG NL Feekes 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 3,5 7.0-9.0 G VG VG E E E VG NL Feekes 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.