A dry year like 2012 is the perfect year to test any new products being released to control soybean cyst nematode (SCN), according to industry experts. Luckily, two new nematicidal products are being tested this year that currently show promise in protecting roots from early-season SCN root feeding.
“The newest development in SCN management is seed treatments,” says Greg Tylka, Iowa State University Extension plant pathologist. “There are two that will be available in 2013: Avicta (sold as Avicta Complete), from Syngenta, and Votivo (sold as Poncho/Votivo), from Bayer CropScience. Both products are positioned to protect root systems from nematode feeding early in the season.”
Despite an upsurge in SCN reproduction on resistant soybean varieties in recent years, most farmers have yet to see huge yield losses on those beans, Tylka notes. “However, that increase in reproduction on resistant soybean varieties, combined with very dry soil conditions, may cause more damage to both resistant and susceptible soybean varieties in 2012 than ever before,” he adds.
“In a drought year, if there is any SCN feeding on roots, the plant will readily show it,” Tylka explains. “Root stunting causes more damage in a drought year than in a year with plentiful rainfall. Also, there seems to be greater reproduction of SCN in dry soils, although that hasn’t been proven experimentally.”
Soybean growers may be unaware that SCN has been the cause of yield loss in their fields in previous growing seasons and may be surprised to see more observable damage this year, Tylka notes. “Farmers have been losing yield to SCN all these years, but it’s not been very noticeable in terms of stunted and yellow beans, because rainfall has been sufficient or even excess,” he says. “This year, yield loss from SCN is going to be much more dramatic and obvious.”
Avicta Complete Beans
Plot comparisons this summer between Syngenta’s Avicta Complete Beans and untreated fields highlight the success of the nematicide seed treatment, reports Palle Pederson, Syngenta Seedcare technology manager.
“The Avicta nematicide offers early-season protection up to 40 days and when used in combination with genetic resistance, it provides full-season protection with multiple modes of action,” Pedersen says. “Avicta Complete Beans works from day one as an early-season nematicide product. Avicta is very reliable; it is not dependent on environmental conditions, soil types, pH or other factors to protect your seed and its roots. It works as soon as you plant it, and it works on most nematode species that are pathogenic on soybean.”
Last year, Avicta Complete Beans was a pre-launch year for the Midwest. “In 2013, it will be widely available,” Pederson says. “Avicta has been used in the cotton market to control nematodes for six years and to control nematodes in corn for three years. Having multiple modes of action using a seed treatment and genetic resistance will really help to protect that genetic yield potential.”
This year, farmers are also seeing good visual benefits when comparing soybeans with Poncho/Votivo seed treatments and those with only a fungicide/insecticide seed treatment, says Ethan Luth, seed treatment product manager, Bayer CropScience.
“Poncho/Votivo provides growers with a unique way to complement the SCN resistance that has been bred into soybean varieties,” he says. “This product includes a biological seed treatment of living bacteria that grows with the root system as it develops, ensuring a more healthy and vigorous plant.”
Poncho/Votivo is the first product in the industry to combine an insecticide with co-formulated bacteria, Luth points out. “The roots of the soybeans emit waste as they grow, and the Votivo bacteria feed off this waste and create a living barrier to keep nematodes from reaching the root system.”
In addition, the Poncho insecticide is absorbed into the plant to offer longer-season plant protection, Luth says. “A major advantage for Poncho/Votivo is its length of protection from insects and nematodes that attack soybeans — up to 45 days viability during early plant growth — and providing protection from second-generation nematodes.”
This is the first year Poncho/Votivo has been available in soybeans and the second year it has been commercially available in corn, Luth adds. In soybeans, it provides early-season protection against bean leaf beetle, aphids, grubs, thrips, flea beetles and a broad spectrum of nematodes, including SCN and the root knot nematode.
“Poncho/Votivo gives an additional 1.5-bu./acre average yield boost on top of a traditional fungicide/insecticide seed treatment, such as Trilex/Gaucho,” Luth says. “That yield boost is an average, both in areas with severe nematode pressure and in areas with low nematode pressure. The yield boost is higher where there is severe pressure. One Indiana grower recently reported a 10- to 12-bu. increase after using Poncho/Votivo in a field with severe SCN pressure.
In 2013, Poncho/Votivo should be available with most major seed brands for corn, soybeans and cotton, Luth says.
University studies are being conducted this summer to confirm product performance. “We have a coordinated project funded by the soybean checkoff through the North Central Soybean Research Program to study the effects of seed treatments on soybean yields and SCN numbers,” Tylka says.
“We’re still trying to determine how the new seed treatments affect nematode populations,” he says. “We might still see a yield benefit without a difference in nematode numbers at the end of the year.”
Soybean roots grow for 16 to 20 weeks. “As that seed-treatment protection wears off, nematodes will have a chance to feed, reproduce and damage roots later in the growing season,” Tylka explains. “SCN-resistant soybeans are not entirely immune. They allow some low level of SCN reproduction. Low-level reproduction means that SCN numbers may resurge after the seed treatment protection wears off in mid to late season and also that resistant soybeans can still suffer some damage and yield loss from SCN if populations are high enough.”
Although more control products are available, there is still no magic bullet for SCN control, Tylka says. “We recommend that farmers plant resistant soybeans and rotate to non-host crops like corn, but now there will also be seed treatments available that might also provide early-season control.”