Syngenta test offers help for managing wild oat resistance
Simple process, valuable results
Posted: November 25, 2008
Farmers with group one resistant wild oats know the challenges of dealing with these weed populations. With resistant wild oat there are very few options for control, resulting in crop yield reductions. Syngenta has announced the launch of the Syngenta AMA Test, a test that can determine group one wild oat resistance and represents help for farmers dealing with resistant wild oats.
The beauty of this test is that it is a simple process for the farmer, it delivers in season results and the test results are definitive because it's testing at a genetic level, says Derek Cornes, Brand Manager for Syngenta.
Within the family of group one herbicides there are three types of products: dims, fops and dens. Wild oats can be resistant to fops but still susceptible to dims and dens so the use of a group one herbicide is not completely ruled out. With group one and group two being the only options for wild oat control in cereals, the loss of the use of one of those is a big problem for the farmer.
The AMA test, which stands for ACCase Mutation Analysis, tests for the existence of three genetic mutations in the plant that confer resistance to all group one herbicides. If only one of the mutations is present, the plants have complete resistance to all group one herbicides but if none are present, the weeds are still susceptible to the dims and dens.
"Because we can tell farmers the exact type of resistance, it leaves them with more options to prevent further resistance," says Cornes. "Farmers can still use a group one, rotate with a group two and protect both pathways of action from resistance."
Diversity prevents resistance
"There are no indications that another mode of action is coming down the line for at least the next 10 years," says Cornes. "So it's in everybody's interest – the farmers, the chemical companies and the industry in general - to protect the chemicals we have against weed resistance."
Maximizing diversity in crop chemical rotations is the best way to prevent resistance. For most rotations, the maximum diversity would be the use of a group one in cereal crop, a Round Up Ready or Liberty Link canola and then group two in the subsequent cereal crop.
"Canadian farmers, for the most part, are very good at proactively rotating chemical mode of action," says Cornes. "Other IPM techniques can be employed, like tillage for example, to help impose as much diversity in weed control as possible. Of course, in a zero till situation, this is not really an option."
The first step is for farmers or their agronomists to contact their Syngenta rep to order a test. The number of tests at that time in the season may be limited in order to keep the target turnaround of one week so booking with Syngenta before sample collection becomes necessary.
After the farmer has been allocated a test, they or their agronomist will take a leaf sample of 40 to 60 plants chosen randomly across the entire field. As with any sampling procedure, submitting a truly representative sample is critical for meaningful test results. The farmer dries down the leaves and then mails them to the lab in the envelope provided by Syngenta.
Farmers can expect results in a week after sample submission which is paramount to making in season weed control decisions. "The tight timeline for testing allows for the greatest probability of product efficacy as the weeds should still be in the proper leaf stage and spray window," says Cornes.
The cost to the farmer is estimated to be $500. "The price tag may seem high for some growers but it doesn't cover the cost of the test," says Cornes. "We won't be making any money out of this program but we see this as being an important element of trying to get people to farm in a sustainable way."
In season results
"Since the test can be done anytime in the season, it can have two separate functions," says Cornes. "It can help with that season's herbicide decisions by telling farmers about the degree of resistance before they spray. Later in the season, the test can provide a diagnostic role by testing weed control failures."
Previously, farmers would have to wait until the weed populations are mature, collect seeds, grow them out under controlled conditions and spray them. Even then, the results are subjective because they are based on the opinion and judgment of the person evaluating the degree of injury or death in the plants.
2008 season pilot
"We are piloting the AMA testing program this growing season with 50+ farmers," says Cornes. "This will help identify and deal with any potential bugs the testing program may come across and get us ready for next season when we will make the tests commercially available to farmers across Canada."
With a target timeline of one week, there could be a limitation in the number of tests available at the time when farmers want results to make in season spray decisions. The pilot will help determine what these numbers are.
The pilot will also help to determine the final costs of the program. "We still don't know what the final cost to Syngenta will be for running the testing program so the pilot will give us some more accurate numbers," says Cornes.
Author: Lindsye Dunbar
Sponsored by: Meristem