5. Do You Need a Seed Treatment?

By Randy Weisz and Eric Stromberg

Seed treatments can be divided into two general categories: standard fungicidal seed treatments, and specialty seed treatments. Standard seed treatments are inexpensive, averaging $1.25 per 50 pounds of seed, and are effective against a broad spectrum of problems including seed decay, seedling diseases that reduce plant stand, and loose smut. These seed treatments may also be highly effective against problems that are most likely to occur in cold wet soils, and that are also more problematic in no-till. Specialty seed treatments, which cost $3.50 or more per 50 pounds of seed, include fungicides or insecticides that are targeted at specific pest problems, such as powdery mildew, Hessian fly, or barley yellow dwarf virus.

Tables 5-1 and 5-2 show the effectiveness of seed treatments against some of the more familiar disease and insect pests of wheat and barley. Of these more familiar pests, wheat seed treatments are highly effective only against powdery mildew, loose smut, barley yellow dwarf, and Hessian fly.

1=highly effective; 2=moderately effective; 3=slightly effective; —=no effect in reducing disease

1=highly effective; 2=moderately effective; 3=slightly effective; —=no effect in reducing disease

Figure 5-1. Risk zones for powdery mildew and leaf rust

WHICH SEED TREATMENT TO USE?

The need for seed treatments depends in part on where the small grain is being produced. Growers in counties with a low risk of powdery mildew and leaf rust risk (Figure 5-1, above), generally will not benefit from a specialty treatment for powdery mildew. Growers in the low-risk zone, especially no-till producers, who are planting into cold wet soils, may benefit from using a low-cost standard seed treatment to protect against seed and seedling rots. Producers in a low-risk zone growing small grains for seed may want to use a standard seed treatment to help keep seedborne pathogens like bunt, septoria, and loose smut out of resulting seed stocks.

Growers in or adjacent to counties in a high powdery mildew and leaf rust risk zone are much more likely to have serious problems with powdery mildew, septoria, rust, and most other diseases. Small grain producers in the high-risk zone, who are not using varieties with good powdery mildew resistance should consider Baytan seed treatment. They should consider a combination of specialty seed treatments targeted at powdery mildew and barley yellow dwarf virus if they are planting earlier than recommended. Standard seed treatments may also help control loose smut and help with stand establishment in cold wet soils, especially for no-till. High-risk-zone producers growing small grains for seed should consider a standard seed treatment to help keep out seedborne pathogens, such as bunt, septoria, and loose smut.

Producers sometimes have problems with barley yellow dwarf or Hessian fly, especially when small grains are planted early. Growers who are planting early and who have a history of problems with either of these two pests may benefit from a specialty insecticidal seed treatment.

Table 5-3 lists standard and specialty seed treatments commonly used in North Carolina.

* Disease and insect pests for which the seed treatment only provides a limited control or suppression, are not listed.

** Always use seed treatments according to label instructions.

This file is a chapter from Small Grains Production Guide, 2004-05. Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the NC Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your county Cooperative Extension Center.

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North Carolina Cooperative Extension Service

Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age, or disability. In addition, the two Universities welcome all persons without regard to sexual orientation. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.

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Last Revised Sept. 2004