Why Do We Spray?

There was a time, not too long ago, that June and July were relatively quiet months on the farm. Once in-crop weed spraying was finished, work in the fields was essentially completed. Farmers were able to spend their summers getting ready for harvest, taking care of unseeded low-lying areas in their fields, and attend weddings and other social events.

Summer this year has been a whirlwind so far. In-crop spraying was completed about two weeks ago (mostly), but fungicide season has only just gotten started. Every sprayer is rolling full out on whatever fields are ready to spray, and farmers are busy checking the rest of the fields to see if they are ready. It is not unheard of to spray 40,000 acres per season, per sprayer.

Perhaps I should explain what I mean by “in-crop spraying”. After seeding is complete in late May to mid-June, crops must all be sprayed to kill weeds. Make no mistake, this is a critical application, as a crop left to fight weeds on its own can be quickly overwhelmed by competition. Thanks to genetic modification, many of our crops are easy to deal with, such as corn, soybeans and canola. Some are also very competitive, like wheat and barley. However, crops like peas and lentils, even with proper herbicide application, can easily be outcompeted by difficult weeds like kochia, wild buckwheat, wild oats, etc. Spraying these crops is a big project and it takes many hours on the sprayer; but it is not the final application of the year.

As soon as the weeds are taken care of, crops are carefully monitored for disease and insects. Most diseases need wet, humid air and warm temperatures for optimum growth and infection. These diseases are mostly fungi, with a wide variety of species infecting each crop. In wheat, tan spot can be very damaging to the leaves, removing photosynthetic area and replacing it with tan-coloured spots. In canola, white mould can devastate yield potential, choking off the stem and starving the plant. In other crops such as lentils, some diseases can virtually kill an entire field in a matter of days (e.g. Anthracnose).

From the outside looking in on agriculture, you may wonder why we spray so many chemicals on our crops. We would not spray fungicides if we didn’t need to. These are expensive products that require many hours on the sprayer to apply, and many of them have extremely tight application windows. Also, during the summer months, I can guarantee you every farmer would rather be at the lake than spraying non-stop.

Take Fusarium Head Blight (FHB) for example, caused by Fusarium graminearum. This disease, if left unchecked, infects the seeds of durum, wheat and barley, elevating levels of a vomitoxin called deoxynivalenol (DON). As the name suggests, this toxin induces vomiting and can be dangerous if consumed in high enough levels. Therefore, if our grain is infected with FHB, it will be worth a lot less to try and sell. Would you want to eat bread or pastries or drink beer infected with this? It is a difficult disease to control, and we check our durum daily to try and catch the optimal window for fungicide application, which is about a two-day opportunity while the head is flowering. A wheat head that has completed flowering, and therefore moved past its application window, is shown below:

Nikon J1 July 351

We sprayed this crop to protect it from FHB, as climatic conditions are perfect for its development. Unfortunately, we also had to apply a product that everyone hates: chlorpyrifos, also known by its brand name, Lorsban. This product is an insecticide, and yes it is somewhat hazardous. We applied it to protect our crop from the dreaded grasshopper. These verocious insects can eat a lot of material very quickly. To compound the problem, we also found some of these bugs:

 

20170704_205521

This little bug on the wheat head is called the orange blossom wheat midge, a nasty little insect that lays its eggs in the florets of wheat and durum, which hatch later on and chew on the developing kernel. Like FHB-damaged kernels, this also causes grade loss.

Spraying insecticides is not a fun job, but sometimes it is necessary to protect the massive investment we put into our crops every year. We avoid spraying them as much as we can, but you do not have to worry about their safety. There is no kernel, or any form of it, in that wheat head yet. Lorsban has a residual of about 7 days. This plant is at least 40 days from harvest. All of our insecticides, indeed all of our chemicals, have a regulated pre-harvest interval to ensure no residue remains at harvest. Furthermore, scientists have developed economic thresholds to determine when it is worth spraying insecticides to prevent unnecessary spraying. Believe me, if I didn’t believe this our food was safe after spraying with insecticides, would I really be out there spraying it? Would I eat it with my family?

The reason I have covered this in such detail isn’t to tell you how tough farming is. I love farming, and I couldn’t think of a career I could enjoy more. I tell you this so that you may know why we do the things we do. Contrary to popular belief, we don’t smother our crops with pesticides; we target herbicides (kills weeds), fungicides (kills fungi) and insecticides (kills bugs) to specific fields that require them. Someday, maybe we will have better tools that allow us to reduce pesticide use (genetic engineering is by far the best path forward for this), but for now, these are the best options we have. And the reality is, for the most part, they have been proven safe by journal article after peer-reviewed journal article.

That’s my rant for today. Hopefully I can get back on this blog more often in the future, as fungicide season will only last another week or so. I am looking forward to its conclusion. It has been a busy spray season!

Oh, one more point, in case you were wondering how the “summer of storms” has progressed since my last post about it. Immediately after that post, some fields got 3 inches of rain. Yeah. Not good. But things have improved since, and because of near ideal weather in the past two weeks, we are now looking at the potential for a very nice crop. Our fingers are crossed!

If you disagree with me about pesticides and their safety, please comment, and I’ll be happy to discuss it with you. This is a subject I take very seriously, and I have done a great deal of research on it.

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