Seed treatments guard valuable biotech seeds against diseases and insects.

Seed treatment is one area of the crop protection business that continues to grow.

The increased value of biotech seeds has increased farmers' interest in seed treatments. Seed treatments protect seed from early-season soilborne disease and insect pests and help assure good, uniform stands. In the next few years, seed treatments are expected to control an even broader range of pests.

Corn seed treatments. Adage, a new systemic insecticide seed treatment from Novartis Crop Protection, is expected to be registered for sorghum, canola, wheat, barley and cotton in late 1999 or early 2000 and for potatoes and corn in 2000. Adage controls soil insects and early-season sucking and chewing pests, such as chinch bugs, aphids, greenbugs, fireants, wireworm and seedcorn maggots. It also has some activity against corn rootworm. The highly systemic product moves into the growing plant's root and green tissue. This slurry-applied commercial treatment will be offered by seed companies.

According to product manager Mark Jirak, Adage will be used at significantly lower rates than Gaucho, a systemic insecticide seed treatment that's currently registered for sorghum and costs about $7 to $8/acre. Gaucho-treated seed is planted on about one-fourth of all sorghum acreage. Adage's lower rates have been shown to offer greater seed safety. It also has eight times the water solubility of Gaucho for more consistent performance in dry conditions, according to Jirak.

Novartis Seeds is evaluating another insecticidal seed coating for corn rootworm control. This unnamed product may be released within the next two years. The company also expects to offer hybrids with built-in rootworm protection by 2003.

Jirak believes that, rather than diminish the market for seed treatments, biotech corns with built-in resistance to corn rootworm may generate greater interest in seed treatments. "There are two possible scenarios," Jirak says. "If the genetically modified [GM] corn does not completely control corn rootworm, Adage may provide the extra level of protection they need. If the GM corn does completely control corn rootworm, farmers probably won't use an in-furrow insecticide so secondary pests like wireworm and seed corn maggot could become more of a concern. "

Currently, seed companies have access to a new, nonsystemic commercial seed corn treatment that protects the seed from corn wireworm and seed corn maggot. The product is called Assault. It adds $1.75 to $2/acre to the cost of seed. Circle 209. Its counterpart for on-farm hopperbox treatment is called Kernel Gard Supreme from Trace Chemical, Pekin, IL.

Soybean seed treatments. "More soybeans are being treated with fungicides because the value of biotech beans clearly justifies the value of seed treatment," notes Ray Knake, northern R & D manager forGustafson, Des Moines, IA. "As farmers plant larger acreage, they stretch the ideal planting window, and the chance of having a stand problem increases. The cost of replanting and the potential yield loss are too great for them not to protect the seed." He claims that sales of soybean seed treatments have been growing 25% per year for the last five years. Allegiance and Apron can be applied by seed companies or farmers to protect soybeans from soilborne diseases and pests.

Gustafson also offers a product to seed companies that prevents the spread of white mold via seed. The product, Rival, can add $1.50 to $3 to the cost of a bag of seed. It stops the fungus from growing and becoming a problem in fields that have not been exposed to white mold.

It's been found that soybean seed can carry the white mold fungus from infected fields to uninfected fields. Rival is also effective against seedborne pod and stem blight and soilborne Rhizoctonia.

ApronMaxx is a pre-pack of Apron XL and Maxim. It is the first complete seed treatment for soybeans, controlling all the major seedborne and seedling diseases of soybeans including pythium, early season Phytophthora, Rhizoctonia, Fusarium, phomopsis, seedborne Sclerotinia (white mold) and seed rots. Maxim was recently registered on soybeans and 200 crops.

Temperature-sensitive polymers. Intellicoat began field trials of seed coated with temperature-sensitive polymers in 1992. The coatings on the seed prevent it from germinating until a certain soil temperature or number of heat units is reached. Originally, the company focused on extending farmers' planting window, but wide variation in hybrid maturities and environmental conditions have made it a difficult task. Now the company is focusing on higher-value niche markets within field crops.

Ray Stewart, senior vice president for Intellicoat, says that the company expects to have a commercial product in 2000 for use in hybrid seed corn production. To create a hybrid, seed companies stagger the planting times of male and female inbreds to match pollen shed periods. Intellicoat is designing seed coatings that will eliminate the need for split plantings and increase the pollen shed window. The coatings will provide a specific "delay" of the required number of heat units. Some inbred combinations require a 50-heat-unit delay, others a 200-heat-unit delay. Several seed companies are testing the coatings. They say that they have the potential to work but that more testing is necessary. Intellicoat also envisions that its coatings will have the potential to extend the pollen shed window for the Top Cross High Oil corn production system.

The coating might be used to expand the geographic area for relay cropping soybeans and small grains. "In this scenario, a farmer in the northern Corn Belt plants winter wheat in the fall and then plants soybeans into the wheat prior to the wheat heading. The soybean seed would be dormant for 25 to 30 days, so during wheat harvest in July the soybean crop would only be 4 to 6 in. tall," Stewart explains.

Several universities are conducting relay cropping trials with Intellicoat to evaluate its potential.