Seed treatment provides an insurance policy for protecting seed until the first shoots emerge. However, there are a finite number of seed treatment products available to Canadian growers that are designed to combat pests and diseases affecting specific regions of the country. As a result, the arrival of new products on the market is always noteworthy—but growers should be aware of the costs and benefits in order to make wise choices.
Two products that have recently launched are Cruiser Maxx Potato and Maxim Liquid PSP by Syngenta. According to Khalil Al-Mughrabi, a pathologist with the Department of Agriculture, Aquaculture and Fisheries in New Brunswick, each of these products has specific qualities that can provide benefits to growers.
The Titan Emesto fungicide/insecticide combo by Bayer CropScience, and Vertisan fungicide and Cyazypyr insecticide from DuPont have been submitted to the Pest Management Regulatory Agency for registration as seed treatments, but are not registered yet for use in Canada.
Liquid Versus Powder?
Cruiser Maxx Potato is a liquid seed treatment that combines an insecticide and fungicide in one package. It controls Colorado potato beetle, leafhoppers and aphids as well as rhizoctonia, silver scurf and fusarium. According to Al-Mughrabi, Cruiser Maxx Potato is a liquid formulation that requires some changes in seed treatment application and handling, as growers have traditionally avoided introducing any moisture to seed potatoes for fear of bacteria growth.
However, liquid seed treatments are becoming more commonplace, as they allow more precise application than powder treatments. Another product that recently made the shift from powder to liquid form is Syngenta’s Maxim Liquid PSP, which controls black scurf, stem and stolon canker, silver scurf and fusarium dry rot.
Titan Emesto is a liquid insecticide and fungicide that, when it receives registration, will be sold as a co-pack of Titan, a broad-spectrum insecticide, and Emesto Silver, a fungicide with two new modes of action for potato seed-piece treatment. Titan Emesto provides control of fusarium, seed-borne rhizoctonia, silver scurf, Colorado potato beetle, aphids, leaf hoppers and flea beetles. It suppresses wireworms only when used at the high rate of the Titan component of the co-pack. Vertisan fungicide is an in-furrow treatment that works against rhizoctonia. Cyazypyr insecticide is an oil dispersion formulation for potato seed treatment, which protects against Colorado potato beetle, European corn borer and flea beetles.
“The focus is to move away from dust material to liquid material,” says Al-Mughrabi. “Environment and Health Canada want to make sure that when workers apply the product the dust doesn’t affect their health. Most companies started to use liquid formulations for this reason. However, for liquid [products], we need to do a lot of work to ensure they work well, because the last thing you want to do when you have a problem with potatoes is to add moisture to them.”
Management of the extra moisture should not intimidate growers, as long as they are following the rules. “If you do apply the product at the right amount at the label rate, and then make sure that the seed is stored—if you have to store it you should store it in an area with good air circulation—so moisture does not build up, [and] so that the tubers dry and no bacteria can invade,” says Al-Mughrabi.
As always, best management practices are key to a healthy start for potato crops, regardless of the treatments growers choose.
“Using chemicals alone isn’t really enough when it comes to integrated management,” emphasizes Al-Mughrabi. “Use of chemicals is one of the tools, but usually I say start with healthy certified seed, as this is the best way to start the crop. Then you can also protect that seed from diseases and insects by using seed-piece treatment.”
Best management starts with healthy seed, and must be carried right through the seed treating process. According to Al-Mughrabi, in the best case scenario, growers should cut the seed, treat it and plant it immediately without storing it, and thus avoid the potential for infection in storage. “What we now tell growers is to cut the seed, treat it and plant it,” says Al-Mughrabi.
If growers are forced to store treated seed, however, careful management of the process can also prevent disease and seed piece decay. After cutting seed, growers should treat the seed to prevent infection, and then store it in an area with excellent circulation, so moisture does not build up and the tubers have a chance to dry. “Make sure to disinfect cutting tools as often as possible” says Al-Mughrabi. Growers should read and follow label directions and recommendations before using any product. This is a good practice which should be followed in order to achieve best results and efficacy.
Once planted, if it has been managed appropriately, the seed treatment should take care of the rest—at least until the first shoots emerge and the rounds of foliar applications begin.
The print version of this article, which was published in the winter 2012 edition of Spud Smart, incorrectly stated that Syngenta’s seed treatment product Maxim Liquid PSP “controls black scurf, stem and stolon canker, silver scurf, Colorado potato beetle, aphids and leafhoppers.” The product’s label states that Maxim Liquid PSP is a “seed piece treatment fungicide for use on potato for the control of black scurf/stem and stolon canker, silver scurf and fusarium dry rot”; the product is not designed for control of Colorado potato beetle, aphids or leafhoppers. Growers are advised to always read and follow product label directions.