Cause: (Puccinia triticina) Occurrence: mid-May - early July; September October. Circular to oval reddish-orange pustules on leaves; orange spore rub off onto fingers.
Plant varieties with at least a moderate level of resistance. Use variety complementation by selecting varieties that differ in parentage, maturity and disease reaction. Consult the Nebraska Seed Book, Fall Planted Crops published by the Nebraska Crop Improvement Association for current information on wheat varieties recommended for Nebraska.
Apply a fungicide based on the following criteria:
· Severity of rust in Oklahoma and Kansas in May (source of rust inoculum for Nebraska).
· Earliness or lateness of the winter wheat crop (late crops more at risk).
· Susceptibility of varieties grown.
· Current and 30-day weather forecasts for mid-May to mid-June (wet weather favors rust).
· Irrigated or dryland wheat (irrigated more at risk).
· Note when rust is first detected on lower leaves (early rust increases risk).
· Potential yield of crop should be at least 45 bu/a dryland and 75 bu/a irrigated.
Goal of a spray program is to keep the flag and flag-1 leaves free of infection since they contribute significantly to yield.
Product list for Leaf Rust:
Fungicide Trade Name |
Product per acre |
Application Frequency (days) |
Remarks |
|
Quadris (azoxystrobin) (Syngenta) |
6.2 - 10.8 fl oz |
Feekes 6 (immediately after jointing) to 10.5 (late head emergence) |
Apply sufficient spray solution to ensure good coverage of the leaf surface. Read and follow all label directions for mixing and application. |
|
Stratego (propiconazole + trifloxystrobin) (Bayer) |
10 oz |
Feekes 8 (emerging flag leaf) |
Apply sufficient spray solution to ensure good coverage of the leaf surface. Read and follow all label directions for mixing and application. |
|
Tilt (propionazole) (Syngenta) |
4 fl oz |
Feekes 8 (emerging flag leaf) |
Apply sufficient spray solution to ensure good coverage of the leaf surface. Read and follow all label directions for mixing and application. |
|
PropiMax EC (propiconazole) (Dow AgroSciences) |
4 fl oz |
Feekes 8 (emerging flag leaf) |
Apply sufficient spray solution to ensure good coverage of the leaf surface. Read and follow all label directions for mixing and application. |
|
Manzate 75DF (mancozeb) (Griffin L.L.C.) |
2 lb |
Feekes 10 (boot) and again at Feekes 10.5 (late head emergence) |
Apply sufficient spray solution to ensure good coverage of the leaf surface. Read and follow all label directions for mixing and application. |
|
Dithane DF F-45 M-45 (mancozeb) (Dow AgroSciences) |
2.1 lb 1.6 qts. 2 lb |
Feekes 10 (boot) and again at 10.5 (late head emergence) |
Apply sufficient spray solution to ensure good coverage of the leaf surface. Read and follow all label directions for mixing and application. |
|
Pencozeb 80WP 75DF (mancozeb) (Elf Atochem) |
1-2 lb 1-2 lb |
Feekes 10 (boot) and again at 10.5 (late head emergence) |
Apply sufficient spray solution to ensure good coverage of the leaf surface. Read and follow all label directions for mixing and application. |
The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality. |
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Categories: Small grains, Diseases, Leaf Rust
Date: 09/11/2004