Why Do We Treat Seed?
Seed Technology Workshop - Olds College
Updated November, 2004
A brief summary of cereal seed treating.
Why Do We Treat Seed?
- Seed treatment provides the least cost and lowest applied dosage method of pest control.
- Minimizes the dosage on the field - reducing residues or harm to non targeted organisms;
- Minimizes volume and cost of product;
- Eliminates application cost and timing concerns;
- Provides initial + advanced pest control to plant.
- Old reasons to treat
- Seedling blights, Smut, dwarf bunt control; inoculants.
- New reasons to treat
- Expanded chemical control options - scald, takeall, karnal bunt.
- Pulse diseases now chemically controllable - ascochyta, root rots.
- Long term insect protection.
- New tank mixes - fungicides + insecticides, or fungicides + inoculants provide more accurate, economic benefit delivery.
- To arrest seed based disease spread - fusarium, karnal bunt.
- Seed treating benefits come from 3 sources:
- Pest control in the crop;
- Limiting the spread of pests to new fields. (Fusarium, smut, bunt,);
- Adding yield potential to the crop via growth enhancers. (inoculants, Jumpstart, micros, etc.)
Requirements of an effective seed treating system (Seed Enhancement)
- Supply an accurate chemical rate to the seed.
Requires control of;
- Chemical flow rate;
- Seed flow rate. Both flows must be uniform and stable.
- Ratioing the chemical to seed volume .
- Apply an accurate, uniform dosage to each kernel.
Pest control field benefit is the sum of each plant's health. Accurate and uniform kernel dosage best provides this.
- Rapid throughput for "just in time" (JIT) spring delivery.
- Accuracy of +/- 5 % to deliver maximum potential benefits.
- Ease of operation and maintenance.
- Affordable cost.
How accurately are treatments applied?
Good chemicals poorly applied result in loss of almost all benefits.
Some seed treating applicators drip liquid product on the top of seed flows in augers. As the following chart, from the Olds College Seed Tech. Workshop shows, as a gravity dripper reservoir empties, the discharge flow changes dramatically. Adding this variable application rate very poor seed distribution uniformity makes drippers a poor method of application. Crop protection is almost all lost.
|Dripper Application Rate as Container Empties|
- Rate Accuracy
- Applied rate is erroneous by 25 to 50 %, even if initially correct rate can be established?
- All product is applied to the small portion of the seed initially contacted - 15%?, resulting in an primary applied rate of 100 / 15 = 6X (6 times recommended) on those seeds and 0X on most of the balance. For some products this will be toxic to the seed, inhibiting germination and vigor.
New Seed Treating Trends
- Trend to seed based pest control, rather than post emergent field applications.
- Lower applied product cost - reduces cost of crop protection.
- Targeted application - helps the crop; not the weeds
- Lower field chemical loading - fewer residual problems.
- No separate application need or timing concern.
- Time of treating changing to "just in time" to reduce hazards of:
- Prepaying seed / treatment costs that may not get seeded. - $$.
- Disposal of treated excess seed - $$
- Storing treated seed - bin contamination / seed quality droop?
- Degradation of treatment and seed with multiple handling.
- New pressures on plant health.
- Zero till, continuous cropping, and less genetic resistance to disease, all put added stress on seed health.
- Better chemical on seed safety
- Less seed damage at high application rates allow higher dosage levels for longer plant protection. This is most evident in the new series of insecticides.
- Multiple treating products with different characteristics vs. only 1.
- Color treating is not possible due to dye level differences in various products.
- Products will have variable local attraction, depending on the local pests.
- Seed and treating products are getting more productive and costly.
- Higher cost and yield potential of seed and chemical requires better application quality, to access the benefits.
- Producers benefit from enhanced seed treating because it's the least cost method of getting better field returns from their inputs.
Our Primary Focus
Maximize the seed treatment benefit to the crop in the field.
Make seed treating accurate, simple and safe.