Not all pests occur in all places. Pests, like insects and diseases, have co-evolved with the plant species that they attack, often in the geography where the crop was first domesticated. Sometimes by moving the crop to a new location, farmers can avoid the pest. Eventually the pest tends to catch up and, with the intensity of modern travel, pest redistribution is inevitable.
The most successful examples of avoiding pests involve growing crops like fruits and vegetables in Mediterranean climates (e.g. California, Italy, Spain, Northern Africa…) where there is little or no rain during the growing season. Without moisture on the leaves of their crops, farmers can avoid many fungal diseases. This of course requires irrigation.
Farmers also have some other, successful, long-term means of avoiding a pest. The San Luis Valley in Colorado is surrounded by high mountains and has cold winters. Insects that spread viruses to potatoes cannot survive the winter there, and the mountains prevent their arrival during the growing season. For that reason, and because it is important for farmers in all areas to plant virus-free potato seed tubers, the potato seed crop industry thrives in the valley. Sometimes the planting date of a crop can be modified to get a crop through a critical stage for pest damage either before or after the time when the pest arrives in a given region. Unfortunately, this strategy becomes more difficult to employ in a time of changing climate.
In some high-tech greenhouses and vertical farming systems, it is possible to completely exclude pests using physical barriers and by using hydroponic growing systems to avoid exposure to the pests that reside in soil.
Although this approach is too capital-intensive for most crops, it is very effective for high value vegetable and fruit crops and is a rapidly growing segment of agriculture around the world.
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