Vegetable Seed Treatments

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» Seed treatments help protect vegetable seed and seedlings from soilborne and seedborne pathogens and insect pests.
» Seed treatments can improve stand establishment, survival, and product quality.
» A combination of chemicals are often used to manage a variety of pests and pathogens.

Seed treatments include chemicals and procedures that are used to protect seeds and seedlings from seed- and soil-borne pathogens and pests. Seed treatments can be especially helpful on seeds planted into cold, wet soil, as slow germination and growth can increase the susceptibility of seeds and seedlings to insects and pathogens. Seed treatment products are usually applied to the seed at very low rates, and they may be more cost-effective and result in lower amounts of active ingredients released into the environment as compared to post-emergent treatment methods.^1,2

Seed treatments include the application of chemicals including bactericides, fungicides, and insecticides. Some seed treatment products include combinations of chemicals to target a range of pathogens and insects (Table 1). A qualified commercial seed company or seed dealer can apply seed treatments that are intended to support improved seed germination, vigor and protection against pathogens.^1,2

Several fungicides are used for treating vegetable seed (Table 1). Some of the fungicides, such as captan and thiram, are broad spectrum and are used to protect against a wide range of fungal pathogens. Other fungicides have narrower spectra of activity and are used to protect against particular groups of pathogens. Many vegetable seed treatment products, such as the FarMore^® Seed Treatment Technology products, contain a combination of a broad-spectrum fungicide and a narrow spectrum fungicide to manage a specific pathogen group. For example, most of the broad-spectrum seed treatment
fungicides are not effective against the oomycete (water
mold) group of fungal-like organisms, including species of
Phytophthora and Pythium, and the downy mildew pathogens.
To protect against these pathogens, a fungicide specific for
that group, such as mefenoxam or metalaxyl, is included.
Products may also combine two broad-spectrum fungicides
with somewhat different ranges of pathogens against which
they are effective.

Most of the insecticides used for seed treatment are able to manage a wide range of insect pests. Currently, the neonicotinoid class of insecticides (or neonics) are commonly used to protect seeds and seedlings against a wide range of insect pests. The neonics are often less toxic to mammals and birds than are the organophosphate and carbamate classes of insecticides.³

However, the dust from treated seed may be a source of honey bee exposure to neonics, so care should be taken to minimize the release of this dust into the environment. The insecticide spinosad is a natural chemical derived from a soil bacterium, and it can be used as a seed treatment for onion maggot and seedcorn maggot on onion.

Seed sanitation procedures can be used to clean the seed, and may also eliminate some pathogens from the seed. These procedures include hot water treatments and soaking seed in dilute solutions of bleach or hydrochloric acid (HCL). These sanitation procedures are often used to eliminate seedborne bacterial pathogens.^1,2

The decision on whether or not to use a seed treatment, or which seed treatments to use will depend on the condition of the seed, the environmental conditions at the time of planting, and the pests and pathogens commonly present in the area or region. A seed treatment option that is very effective in California may not be appropriate for the conditions in the northeastern region of the U.S. Consult with an extension specialist, crop-consultant, or seed-dealer to determine the best seed treatment options for your region and conditions.

Table 1. Click to view PDF version.