by Lance Hill | Jun 28, 2025 | How To, Mirliton
Lesion with salmon-colored fruiting bodies (acervuli)
Tim Dill recently posted a photo of his mirliton vine that looked like it was on its last leg. Many people weighed in on what they thought the problem was: squash vine borers, insufficient fertilizer, drainage, and plant disease. However, the long view of his vine did not provide enough information to diagnose the problem, so we requested close-ups of the vine, and Tim delivered.
The photo clearly shows the early stages of anthracnose. This is what is known as a lesion, and the black spots are referred to as “fruiting bodies” (acervuli), which contain spores that spread the disease. The fruiting bodies start as salmon-colored dots and then turn black as the disease progresses. Additionally, small gummy drops of exudate will eventually appear, and the stem will split open. The leaves will have yellow wedges, and in the final stages, they will develop “rifle shot holes” in the brown, dead tissue. That’s because the fungal pathogen that causes anthracnose is necrotrophic, meaning that after it kills the plant cells, it can feed on dead tissue as well.
Tim’s problem was not caused by too much or too little water, too much sun, or insufficient fertilizer. And all the remedies for those causes would not have helped and probably would have done more harm.
So the first question we should always ask is for good close-up photos of the leaves and stems. Most smartphones can take a photo that can be magnified if needed. Videos are better than nothing, but only photos permit a close examination of the leaf and stem symptoms.
You can learn how to diagnose anthracnose for yourself and others by viewing this photo album of anthracnose signs (click on the first photo in the series to enlarge the images).
https://www.mirliton.org/photo/anthracnose-damage-to-mirliton-plant-parts/
We used to never see anthracnose this early in the season. However, the periodic rains and warm nights create a perfect storm for the fungus; it thrives in the nighttime heat, and then rainfall ruptures the fruiting body, splashing the spores throughout the plant during the day (or top-down watering).
There’s no cure for anthracnose once it takes hold. Daconil is often prescribed for anthracnose, but it is not a fungicide and can’t kill the fungus that causes anthracnose; it simply coats the plant with a film that makes it more difficult for the fungus to attach to the stem and leaves. It’s a preventative, not an eradicant, and would have to be applied from the time the vine was planted and throughout the season.
We are testing a new biofungicide, Timorex Act, and will report on our findings when the trials are complete.
The good news is that normally, the vine will recover from an attack and produce in the fall–and will have acquired natural resistance to the disease.
Advanced lesion with black fruting bodies (acervuli)
Lesion with salmon-colored fruiting bodies (acervuli)
Gummy edudate.
Perfect example of anthracnose wedge-shaped sign on leaves–including the “rifle shot” hole. The fungus first feeds on living tissue, and then lives on dead tissue.
by Lance Hill | Jun 26, 2025 | How To, Mirliton
Alternaria Leaf Blight
Alternaria leaf blight in mirlitons, caused by the fungus Alternaria alternata, occasionally occurs in the U.S.A. The disease manifests as yellow, irregular spots that appear on leaves, often with a brown center. It’s often a secondary infection when the vine becomes stressed and weakened by excessive rains. It frequently affects new mirlitons in the early stages of growth.
Since it primarily affects leaves, it is not lethal and the vine will survive, but it can reduce the canopy.
It’s a waterborne fungus, so rain and overhead watering will spread it. Avoid overhead irrigation and remove and destroy infected plant material promptly to reduce the source of inoculum.
by Lance Hill | May 12, 2025 | How To, Mirliton
By Lance Hill and Kevin De Santiago
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. 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 temperatures 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 use imported mirlitons to grow a vine.
Second, even if you could grow an imported mirliton, you may introduce new diseases that have devastated mirlitons elsewhere. Local mirliton varieties that are adapted to conditions in the U.S. 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 by 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 from imported chayote sold as produce in grocery stores. Although no new mirliton diseases have been discovered in the U.S.A., it’s a widespread problem with other imported seeds, such as Tomato brown rugose fruit virus (ToBRFV) in tomatoes. The recently discovered Chayote Mosaic Virus (CMV) can be transmitted inside infected mirliton fruit without any sign of infection (seedborne and sapborne diseases). 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 you can potentially destroy all U.S. varieties. Read about CMV here.
In Brazil, scientists have recently discovered new fungi that cause anthracnose disease in mirlitons–also another soilborne and sapborne disease that can be spread through imported chayote. 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. It is best to wait until you find one of the Certified Louisiana Heirloom Mirlitons available on Mirliton.Org.
by Lance Hill | May 4, 2025 | How To, Mirliton
Where Should I Plant My Mirliton to Get the Ideal Amount of Sunlight?
The answer: Just about anywhere.
Mirlitons can be initially planted in partial shade or full sun. If planted in a well-shaded area, they will naturally send out shoots to the greatest amount of light. They are “sunseekers” in the sense that they will always grow from shade to full light. You can plant them in partial shade, and as long as the trellis guides them toward more sun, they will follow that.
They can also be planted in full sun. But under the new weather conditions of heat domes and intense heatwaves, we have found that it is absolutely necessary to use a 40% shade cloth, especially when the temperature is excessively high — 95℉ for several successive days. That is why we advise growers to always build a structure along with the trellis where they can quickly and easily mount a shade cloth.
Many growers use shade cloths throughout the growing season. While I don’t think it’s necessary to use them when the temperatures are in the low 90s, it may not hurt. But there are two downsides to using a shade cloth too early in the season. (1) It reduces the amount of light necessary for photosynthesis, which provides the vine with energy and drives new growth–particularly for a young vine. And (2) shade cloths reduce the amount of ultraviolet light, which is a natural fungicide and helps combat fungal diseases.
Bottom Line: You can start your mirliton in almost any available lighting. Just plan to protect it from too much light. Build a structure along with the trellis so they can quickly and easily mount a shade cloth, which can also double as a rain guard during excessive rainfall.
Angela Joan’s shade cloth draped over the vine, supported by poles.
by Lance Hill | Apr 28, 2025 | How To, Mirliton
Tedra Erikson Stanley performing the thumbnail test.
Mirlitons are typically ready to harvest when they reach approximately 8 ounces, although size and weight can vary. The most reliable method for testing for harvesting is the thumbnail test.
Start by pushing on the fruit skin with your thumbnail. If the fruit skin dents or even seeps a little moisture, the fruit is still immature and will be too watery. If it is firm and does not dent, you are ready to pick. The old growers used to say, “My mirlitons are hard now and ready to pick.”
See Tedra Stanley’s video on how to do the test here.
At the hard stage, they are also mature enough to sprout and or use as seed. But once they begin to sprout, they’re too tough to cook.
by Lance Hill | Apr 23, 2025 | How To, Mirliton, Uncategorized
The spring harvest of mirlitons has increased in recent years due to advancements in growing techniques. The question is: How do we plant them?
There are two options: container-grown plants or planting them directly in the soil.
First, in either case, the fruit needs to be spouted. This ensures the seed is viable, and a sprouted mirliton means the roots and shoots are ready for soil and will quickly root and grow. You can expedite sprouting by incubating the fruit. If kept warm, they will sprout within 7 to 14 days. Read how to do it here. (We encourage growers to also incubate their sprouts before selling or gifting them, for the same reasons.)
Once the seed has sprouted:
Container planting: Plant it in a 3-gallon container and keep it outside in the shade for the summer. Use a small tomato cage for a trellis. Mirlitons can be easily pruned back to maintain a compact shape if desired. Transplant them into the ground in September, after the danger of the heatwave has passed. Cut it back and mulch it in November, or tent and heat it for the entire winter. Either way, you’ll get a good spring crop. Use the bamboo stake technique for gauging watering needs.
Mirlitons trellised on tomato cages.
Direct planting: This is a little more tricky. You can plant sprouts in May or June, but they will need to be initially shaded from the heat of direct sunlight. Place a milk crate over the plant, covering it with a 40% shade cloth or a piece of cardboard to protect it from the sun’s rays. After it starts to grow foliage, remove the crate and shade. Read about shading it here. Use the standard methods for bed preparation in the quick guide
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