This is the third in a series of posts talking about crop-by-crop reasons that pesticides are used. These are reasons that go beyond just protecting the yield of the crop and the inputs of land, water, fertilizer and labor that go into farming – reasons that pesticides are a key part of “sustainability.”
On this post I’ll talk about a few specific examples where the benefit of the pesticide has to do with the time that a commodity (fruit/vegetable) can be available to provide human nutrition and sensory enjoyment – time in storage, time to travel across the country or globe, time to sit in a consumer’s refrigerator. I’ll address the “local question” at the end of this post.
My first example will be bananas – the year-round available fruit that it so attractive to children. In the tropics where bananas grow, they are subject to a fungal disease called Black Sigatoka that infects their leaves. The disease does not directly effect the fruit and the fruit is even shielded from the fungicide sprays for this disease by the protective bags that are put over every developing cluster of bananas.
The disease has to get rather severe on the leaves before it effects the harvested yield, but banana growers have to make fungicide sprays to keep the disease on the leaves below a very specific threshold that they monitor intensively, tree by tree. Why? Because if bananas are harvested from a tree that had too much leaf disease, they can’t make the energy-efficient, ocean shipping trip to markets in the US, Europe and Asia. Bananas from overly infected trees ripen prematurely and when the ship comes into port all you have is a mess of black, decaying fruit like you would see if you leave your bananas far too long on the counter. Banana growers have to spray more fungicides than they need to protect yield to deliver a usable product to remote markets. These treatments buy them time.
My second example has to do with Strawberries, a crop that has come a long ways. There was a time where they looked great but had no flavor and often rotted before you could eat them. Today I can get fantastic fruit in the store. Part of that is genetics. There has been a lot of recent breeding for taste – not just looks and ability to ship.
Part of our increasingly positive strawberry experience is about disease control. There are some new fungicides that do a much better job of disease control, even from early in the season. Because of this, the fruit that is harvested is much less likely to rot on the way to your store or in your refrigerator. The chemicals that make this happen are very “soft” from an environmental or human safety point of view. There are a few, older and not quite so soft chemicals that need to be used as part of the program to prevent the development of pest resistance to these new options. Together, these fungicides allow us to eat good berries.
My third example is potatoes for French Fries. The processing facilities that take raw potatoes and turn them into frozen fries etc involve huge capital investments. They are designed for year-round production and anything less would be very inefficient. To supply those plants without shipping potatoes from long distances (a really bad idea since potatoes are more than 70% water) it is necessary to be able to store potatoes for many months. People have done this for centuries in “root cellars” etc – that was one of the only reasons that “local” worked even for survival for centuries. Growers store potatoes to supply processing plants year-around.
The degree of growing-season pest control that is necessary for potatoes that will be used immediately or in a few months after harvest is qualitatively different from what is needed to store potatoes for many months. Long-term storage potatoes are really a different crop-segment than shorter-term spuds. What is a logical “sustainable” standard for those potatoes is also different.
What about Local?
I know that many readers will be thinking, “but what about local?” Local produce production is a great thing where it works. But “local” can only be a part of a year-round, healthy, and enjoyable diet for people in all but a few places. Frankly, local produce production in many geographies will require its own increased pesticide use because many of these environments are much more suitable for diseases and certain insects than some of the major produce production regions (e.g. the desert West).
So, what I am saying does not negate in any way the role of local production where it makes sense. Still, the need for “time” for many produce items is going to be a continuing need no matter how much momentum the local food movement achieves.
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