Many people want to grow their own mirliton (chayote) vine but find it difficult to find locally grown mirlitons. Because of their frustration, some people try to grow mirlitons by purchasing and planting one from the produce department in a grocery store, or online from seed stores. There are two reasons why this is not ideal.
First, all mirlitons sold in grocery stores and markets are imported varieties. They are grown and imported only as produce, just like all the other vegetables that you purchase. The USDA tried to grow these varieties a century ago and concluded that high-altitude plants have tremendous difficulty growing in low altitudes. This is because these varieties have adapted to the altitude, pests, diseases, and ultraviolet exposure in their native environment. The patterns of light and temperature influence when and if the variety will flower and fruit. Moreover, an imported variety may not have acquired resistance to diseases or disease pressures that occur in its new environment.
All imported mirlitons will sprout and send up a shoot, but most imported mirlitons will not flower and set fruit. We have received reports of this problem from hundreds of growers over the years, and I had the same disappointing experience when I tried to grow a vine using imported mirlitons.
Second, even if you could grow an imported mirliton, you may introduce new diseases that have devastated mirlitons elsewhere. Local mirliton varieties adapted to U.S. conditions have been grown for over two centuries in Louisiana and California. These were originally brought from low-altitude coastal areas in the Caribbean and Central America. In horticulture, these local varieties are called landraces —cultivars that growers have improved through traditional agricultural methods. The Louisiana heirloom mirliton is the U.S. mirliton landrace that has adapted to the regional climate, diseases, and pests through generations of trial and error. They are a reliable and healthy variety.
But they are vulnerable to new diseases. Many mirliton diseases have not reached the U.S, and some, like the destructive Chayote Mosaic Virus (CMV), are transmitted inside infected mirliton fruit without any sign of infection (seedborne and sapborne diseases). The U.S.D.A. does not screen imported chayote for diseases becuase, rightfully so, they assume that it will be eaten, not planted. If you purchase infected imported mirlitons that carry the disease and then plant them, you may spread the disease to the Louisiana heirloom mirlitons.
There is no cure for CMV and other viral plant diseases, and planting imported, unscreened chayote can potentially destroy all U.S. varieties. That applies to both grocery chayote and chayote of unknown origin sold online. Read about CMV here.
Plant diseases are constantly evolving and afflicting chayote. In Brazil, scientists have discovered two new plant diseases in chayote. One is a new fungus that causes anthracnose disease in mirlitons — another soilborne and sapborne disease that can be spread through imported chayote. Read the article here.
Read the article about the new seedborne fungal pathogens that cause anthracnose discovered in Brazilian chayote herel https://www.mdpi.com/2309-608X/10/12/847
And another has been discovered: Cowpea Mild Mottled Virus (CPMMV). Read about it here.
To summarize: Imported mirlitons may not grow and fruit in the U.S., and if they do, they may have disastrous consequences for U.S. mirlitons landraces.