Today there are a number of herbicide options for almost every weed and every crop. Even for your specific situation there is usually a number of herbicide options, so how can you decide what product to use or if you should spray at all? Well there is a number of questions to ask before pulling the trigger.
The first is simply do I need to spray at all? Whether this means not spraying a grassy herbicide or broadleaf herbicide, you may not have to spray one of them depending on the weed pressure within your field. A grassy herbicide is typically very expensive and if your field is relatively free of all wild oats and grassy weeds then is spraying a grassy herbicide economical? Probably not. Sure you can keep the odd one in there from adding to the wild oat seed bank the next year or you simply don’t like seeing those dreaded things popped up above your crop, but saving upwards of $18/ac might be worth viewing that less than perfect picture. A wild oat population of 10 per m squared throughout your field is going to cause a loss of only about 5-7%. Using easy numbers of 5% and a 50bu/ac wheat crop means a loss of about 2.5 bushels. 2.5 bushels equates to about a loss $17.50 at $7/bu commodity pricing of wheat which means that only at about 10 wild oats per meter squared is a grassy herbicide justified. Obviously, you need to take into account dockage and control in following years as well, but that’s a rough picture of what determining economic thresholds should look like.
The next thing to look at is what chemicals control the target weeds in the field. You do not need to buy the best product out there when it isnt justified. Prestige from Dow is a great product, but also very pricey. If you simply are targeting seedlings of red root pigweed, wild mustard and flixweed in your field for example then an application of a product such as Target from Syngenta is sufficient for control of these weeds and saves you a number of dollars per acre. So being aware of your problem weeds and going with a product that gets the job done is fine, you do not have to go with the top product out there all the time. Lots of products have 3 active ingredients these days and that typically means those products are more expensive, if a product has only one or two active ingredients then it is typically cheaper. If the product with only two actives will get the job done on your problem weeds then you should be going with that product to save some extra dollars. The money saved can be put toward an extra burn down active the following year or a post harvest burn off.
Be aware of the stage of the weeds in the field as well. Attain/Octtain from Dow smokes kochia, a typical problem weed in a lot of areas, but a number of other products will work as well that cost several dollars less per acre. If you have kochia in your field that is loonie size then products such as Thumper from Bayer and Target should provide adequate control. Attain will easily control bigger sized kochia, but if you are going to be in the field before the kochia is past seedling size then why not go with a product that saves you a few bucks?
When a products patent runs out that means it is free game to be produced by any other chemical company. These companies that produce generic products once the patent has run out typically sell their product for cheaper than the original version even though the active ingredient is the same. These products will do virtually the same thing to the weeds in most cases and be just as safe on your crop, yet they will be sold for a few dollars an acre less. Be aware of the lack of “backing” if a you run into product issues though.
Lastly, pay attention to company rebates. Lots of the times these days companies such as Bayer, BASF etc will have a rebate program that gives you certain percentages back if you go with their herbicide and fungicide for example. If you know you are going to be spraying a Bayer fungicide on your cereal crop and you have the option of spraying one of their herbicides on your crop and can get a 3% rebate for example from this product combination then you should make the choice to go with the Bayer herbicide.