Cooperative
Extension
Service


University of Illinois
at
Urbana-Champaign


No. 5/April 25, 1997

Wheat Fungicides

Because many fields in southern Illinois are at or approaching flag-leaf emergence (Growth Stage 8), this is the time to consider fungicide applications. Fungicides are available that are systemic or protectant, and producers need to be aware of which kind they are applying. Systemics provide some curative action if infestations are light to moderate. Materials such as Tilt (Novartis) provide broad-spectrum activity but may be limited in the number and timing of applications. Protectants such as mancozeb (numerous companies) must be applied prior to infection to prevent pathogen entry. They are usually less expensive than systemics but may not be as effective, particularly if rains occur shortly after application. Always use a spreader-sticker with wettable powders.

To control common wheat diseases, the following fungicides are suggested:

Common name
Trade name
Comments
benomylBenlateDo not use Benlate alone. Use only in combination with nonbenzimidazolefungicide. Combine with Bayleton or a mancozeb product, depending on diseasespresent. Time application to keep flag leaf free of diseases.
mancozeb

Manzate
Dithane
Penncozeb
mancozeb

Do not make more than three applications per season, and do not apply within26 days of harvest. Do not graze livestock in treated areas prior to harvest.Start applications at onset of disease and repeat at 7- to 10-day intervals.Add surfactant to improve performance.
triademefonBayletonLimited to 16 oz/acre/season and a 21-days-to-harvest restriction. Rotationalcrops cannot be planted for 35 days following last application. Do not allowlivestock to feed or graze on treated plant materials. Future status ofBayleton for wheat is changing. Bayer has announced it will not seek reregistrationon wheat for this product. Currently labelled materials can be applied throughoutthis season.
propicanazoleTiltOne application/acre /season is permitted at flag-leaf emergence (FeekesStage 8). Do not graze or feed livestock the treated forage or cut the greencrop for silage. After harvest, the straw may be used for bedding.

Walker Kirby, Department of Crop Sciences, (217)333-8414