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Identifying and Managing Anthracnose in Mirlitons (Chayote)

by | Apr 23, 2023 |

Mirliton leaf infected with anthracnose. Unlike powdery mildew which yellows uniformly and wilts the leaves, anthracnose starts as yellow wedges between the leaf veins. It then turns the leaf tissue brown and leaves with a distinctive “shot hole.”

Anthracnose is a summer disease caused by many fungi, but the pathogen that affects mirlitons is Colletotrichum lagenarium. For the purposes of this article, I will call Colletotrichum lagenarium the “anthracnose fungus. It is a chronic problem with mirlitons and it’s the main reason plants die the first year. There is no known synthetic or biological fungicide that can prevent or eradicate anthracnose in mirlitons. But anthracnose is like a sprained ankle; you can’t prevent it or take a pill to cure it, but you can minimize the risk of getting it and speed up the healing process.

Anthracnose and powdery mildew (PM) are fungal diseases that start with a common sign; leaf yellowing (chlorosis). It’s important to recognize the difference because powdery mildew can be treated, while anthracnose can’t. The PM fungus spreads on the surface of leaves, initially as faded yellow dots and then yellowing the whole leaf until it wilts and dies. Anthracnose, in contrast, grows inside the leaf cells and spreads cell-to-cell (intercellularly)l, so it tends to spread between the leaf veins and form sharp wedges. It kills the tissue within the wedge spreading across to the whole leaf, so you will see both yellow and brown tissue in the same wedge photo.

Mirlitons tend to experience anthracnose epidemics in July and August because of rain patterns. Intensive rains splash up anthracnose fungi from the ground onto the plant stem. The fungus incubates during warm nights and produces thousands of spores that are contained in a sticky base. Rainstorms dissolve the sticky film which releases the spores. Then, raindrops splash the spores to adjacent leaves–and that’s why anthracnose epidemics occur during the hot rainy season.

Anthracnose infects every part of the vine, including leaves, petioles, and stems. It will eventually split the stem, preventing the flow of nutrients to the ends of the stem, so suddenly a whole section of the vine will wilt and die. The good news is that for every stem lost, a healthy vine will send up a new shoot. It is a tug-of-war with the disease through the summer, but generally, the disease will disappear by September in time for flowering and fruiting.

The key to surviving an anthracnose epidemic is to have a healthy vine in place before the epidemic. That means a well-drained and aerated vine. When the soil is water-saturated and no oxygen is available in the root zone, plants go through dramatic changes to survive. They are literally in “anoxic” soil like the dead zones in the Gulf of Mexico. They shift from aerobic metabolism to anaerobic metabolism: they have only 5% of the energy efficiency they have in healthy aerated soil; they produce toxic organic and inorganic compounds, and they deprive leaves of potassium crucial to maintaining leaf functions. After 24-48 hours, the roots have been damaged making it more difficult for them to uptake water and nutrients. Leaf functions are weakened and the whole plant is vulnerable to disease.

The good news is that a mirliton will acquire increased resistance to anthracnose every time it gets the disease. If your vine gets anthracnose this year, it is less likely to get it next year.

The solutions are simple.

Ground Planting:
Make sure the soil is well-drained and aerated. Plant on your highest area available, use planting hills, and stay away from roofs. Plant near a tree if you have one; trees are natural sponges and tend to stabilize soil moisture. If you already have the vine planted, you can dig shallow drainage trenches to remove excess rainfall away from the vine or add a corrugated drain pipe or a French drain.

Raised-bed Planting:
Remember that a raised bed can’t drain into a saturated yard, so you need to construct a bed that will permit excess rainfall to escape the bed via the sides. Add a lateral route for excess water to exit above ground level by drilling 1/4 “ holes along the side panels.

Summary:
For now, the best protection against anthracnose is (1) to use only locally grown heirloom mirlitons for seed since they are likely to have some resistance to anthracnose; (2) plant in well-drained, aerated sites; (3) provide plenty of trellis space so leaves on top can spread out and get maximum exposure to the sun (a natural fungicide) and air circulation; (4) minimize leaf/soil contact by using an overhead horizontal trellis at least 4 feet above the soil and (5) always irrigate gently with a hose set on low on the surface or drip irrigation to prevent splash-up of soil-borne fungi. Do not water mirlitons from the top down. Once leaves and stems are brown and dead, remove them and dispose of them away from the vine.

Click here to see photos of anthracnose infection signs on leaves and stem at different stages (click on each photo for descriptions)
Click here for how to identify and manage powdery mildew.

What is a Certified Louisiana Heirloom Mirliton?

by | Apr 9, 2023 | ,


Up until about 2020, any mirliton grown in Louisiana was an heirloom mirliton. They were what botanists call a “landrace.” Landraces are domesticated plants that developed over time and adapted to their natural environment and are not the product of human manipulation–such as plant breeding or modern genetic science. Haitians brought the first mirlitons to Louisiana over two centuries ago and that landrace thrived because it was adapted to our altitude, climate, pests, and diseases.

The mirliton landrace is easy to recognize because of its distinctive fruit traits; they are large, slightly pear or egg-shaped, with smooth skin, longitudinal furrows (though a few may be unfurrowed), and either green or white. Over the years other varieties were introduced from Mexico and Central America and interbred with the Louisana landrace. The resulting landrace was what generations of Lousianians simply called “mirlitons.” And for most of the last two centuries, there was only one variety.

Then things changed. After Hurricane Katrina wiped out almost all mirlitons in New Orleans, garden experts advised me to buy any chayote (mirliton) from a grocery store and plant it. That didn’t work because almost all imported chayote grew at high altitudes and would not produce in Louisiana. So I began to search for growers of our Louisiana landrace to replace the New Orleans ones. I soon found many growers in rural areas and when I did, I would name the mirliton after the grower so that we could track and preserve it.

I eventually noticed differences within Louisana mirlitons–there were clearly different subvarieties in the landrace. Mirlitons were more complex than we thought. Since the Louisiana mirliton has never been genetically analyzed, I decided to classify the subvarieties by fruit appearance (morphology), and then interview the growers to determine the strain’s history. If I could establish that the mirliton had been continuously grown for at least two decades, then I named it after the grower. That way we could keep that particular line going. That’s how named varieties came to be.

So there are two categories of Louisiana mirlitons:

1. Unnamed Louisiana Mirlitons is the name for the traditional Louisiana landrace. That encompasses almost any mirliton that was locally grown in Louisiana. We call these “unnamed variety.”

2. Named Certified Louisiana Mirlitons are the few strains within the larger unnamed category that Mirliton.Org has named after investigating and verifying they have been continuously grown for at least twenty years in Louisana. There are currently twelve named certified varieties of Louisiana heirloom mirlitons:

Ervin Crawford
Joseph Boudreaux
Ishreal Thibodeaux
Boudreaux-Robert
Blacklege
Papa Sylvest
Bogalusa whites
Chauvin-Rister
Remondet-Perque
Miss Clara
Bebe Leblanc
Maurin

 

 

Only these named certified varieties have been researched and verified as authentic heirlooms. If you grow one of these named varieties, you can be confident you are growing a Louisiana heirloom.

Why is it important to continue tracking heirlooms? Beginning in 2020, several grocery store chains began to import chayote (mirlitons) that looked exactly like our heirloom varieties because they sold better. And some people began to grow them because they were indistinguishable from our heirloom variety. The problem is that imported chayote may carry a deadly seed-transmissible virus that can destroy the Louisiana variety. It’s called Chayote Mosaic Virus (ChMV), and it’s devastated crops in other countries.

If you want to preserve the Louisiana heirloom variety and keep them safe, the best way is to only use certified heirloom seeds like the ones named above. Mirliton.Org offers a free certification service and maintains a list of certified growers.

We can also certify new varieties that you may come across–and we expect the list of verified ones to grow. If you find a grower who says that their mirlitons were locally grown but have no name, the grower can ask Mirliton.Org to verify and certify them as an heirloom variety. We will do that by examining fruit characteristics, taking an oral history, and conducting visits to grow sites.

Incubating Spring Mirlitons

by | Apr 1, 2023 | ,

Growers normally try to delay mirliton sprouting by putting new fruit in paper bags and storing them somewhere cool. But if you get a winter or spring crop, you may want to get them quickly sprouted so they can be directly planted. Here’s an “incubation” trick that Joseph Boudreaux of Broussard taught me that speeds up sprouting.

 

Once you pick the fruit, place it in a shaded warm area with a constant temperature of at least 75-80°F to encourage sprouting. The warmer the better. In a sense, you are incubating the fruit since cooler outside temperatures promote dormancy and prevent sprouting.  If storing them outside, use chicken wire or netting to protect the seed from pests that enjoy eating the new sprouts. 

 

When kept warm like this, the fruit will normally begin to sprout within 10-14 days. Sprouting is defined by when the internal seed pushes its way to the large end of the seed and a small green shoot emerges. When that happens, it means the seed is viable and can be planted. It’s important to not distribute or sell the seed until it has sprouted because sometimes–especially with Spring mirlitons–the seed can look healthy but have no internal inner seed and will not sprout and grow a new vine (it’s called parthenocarpy). 

 

The shoot should only be a few inches long if you are selling them because long shoots tend to break off at the base during planting–and once broken at the seed, shoots will not regrow.  If the shoot has already grown several inches, you can safely prune it back, but leave a couple of nodes. 

And that’s how you incubate your mirliton.

 

Fertilizing Mirlitons

by | Mar 28, 2023 | ,

 

There has never been a scientific study for home gardeners on how to best fertilize mirlitons,  so we get to invent the science ourselves.  In the growers guide that I wrote several years ago, I recommended  8-24-24 fertilizer. I don’t advocate that specific one anymore. Any fertilizer with a lower percentage of nitrogen (the first number)  such as 5-20-20 will work fine and old-fashioned 8-8-8 or MIracleGro are good choices. A couple of tablespoons at planting and again in July is sufficient—as long as the vine is vigorously growing and green.

 

 But there are two important fertilizing principles I have learned from experienced growers:

 

(1) Use a slow-release fertilizer such as manure. A mirliton’s nitrogen needs vary throughout the growing season. You don’t want to jolt their tender young roots when you first plant them. They like a buffet where they can eat light, but return for more helpings when they need it. Manure provides that. Ideally, work into your soil or planting pit before you plant, but you can side-dress throughout the season. Rabbit manure is the best choice, but any manure will do the job. 

 

(2) If you are using fast-release fertilizers, stop before the flowering season. A dose of fertilizer can delay and disrupt flowering.   

 

I asked our home gardener mirliton scientists last year to tell us how they fertilized mirlitons.  What were the signs it was helping or hurting? Did the experiment with different techniques?  I got these thoughtful responses. Click here to read them.

 

No More Guesswork In Watering Mirlitons: The Soil Sampler

by | Mar 6, 2023 | ,

 

 

 

Excessive rains and prolonged droughts make it nearly impossible to know if we have the right soil moisture for mirlitons.  Extremes in soil moisture–too much or too little–can stress the plant and cause diseases. Mirliton growers in Brazil long ago took the guesswork out of determining exactly how much available moisture lies below the surface. They use an inexpensive “soil sampler” which allows them to take a core sample of their gardens/fields and see and touch the soil at all levels. You can’t beat that.

.

You can buy a small soil sampler for less than $20, or if you are like me and have an old worn-out back, you can get a 36” one with a footstep. Once you pull up a core, you can pop it out onto a table touch the soil at each level and to feel for moisture levels. A mirliton’s primary root zone is in the top 7” of soil, so no more drowning or dehydrating your plants. Watch this clip on how easy it is to use.

Buy the 12” one here

Buy the 36″ one here

Here’s a short video on how to use the “sight and touch” method for the core sample you take.

Preparing for the New Mirliton Season

by | Feb 25, 2023 | ,

  1. Select a plant site. The most important thing to keep in mind is that water-saturated soil can drown a young mirliton. Even if your plant survives intense rains, excessive soil moisture later in the summer will stress the plant leading to anthracnose. Choose the best well-drained site on your property–away from roof run-off and preferably near a tree drip line. The vine does not have to initially be in full sun because mirlitons are sun-seekers and will follow a trellis to available sunlight. Make sure you have room for an overhead or vertical trellis.
  2. Make a bed or a pit.   Mirlitons thrive in loamy, well-drained soil. If you have that, prepare a bed at least 10′ x 10′ which will allow for an overhead trellis that can double as an enclosure for frost protection. Till the soil and add amendments if necessary (if you are using a raised bed, tilling the soil beneath is imperative to ensure bed drainage).  But most growers are not fortunate to have good soil and certainly don’t want to waste a $35 seed on a $1 hole.  In that case, I recommend a planting technique taught to me by Ishreal Thibodeaux of Opelousas: the pit method.  It has been successfully used around the world wherever gardeners have clay or any poor soils. With this pit method, you are essentially building a container below ground and filling it with your preferred soil mixture, just as you would with house plants. First, dig a pit 2’ x 3’ x 18” deep.  Then fill it with a mix of equal parts: (1) the topsoil you removed from the hole, (2) commercial potting soil, (3) compost, and (4) manure (rabbit, if available).  Make enough mixture to also build the hill on top (below).
  3. Build a hill.  Make a 2’ x 2’ hill on top of the pit using the same mix. Transplant your mirliton into that in April or after the normal last frost date and add a wire cylinder trellis so the vine can climb to the overhead trellis.
  4. Assemble your defense force. Prepare now for rain, pests, and diseases. We suggest you buy a: (1) rain gauge, (2) a soil sampler for testing soil moisture (3) potassium bicarbonate for powdery mildew, (4) BT for preventative management of vine borers, (5) sevin for preventative management of stink bugs, and (6) a shade cloth for the first two months of the plant.
    I will post on each step of the growing season in this series, including, disease and pest management, identifying subsurface soil moisture, fertilizing, inducing early flowering, hand pollination, and frost protection through sprinklers and temporary enclosures.

Links:

Soil Sampler for Testing Soil Moisture
Potassium bicarbonate

BT Concentrate

Sevin

 

 

 

 

How To Water A New Mirliton Seed

How To Water A New Mirliton Seed

by | Jan 25, 2023 | ,

The video at the bottom of this post explains in 60 seconds the simple bamboo skewer stick soil moisture technique that will prevent you from drowning your young mirliton. 

 

As you may know, we recommend that you overwinter your mirliton in a 3-gallon container filled with potting soil, which will enable you to transplant the plant in the spring with a healthy rootball. Watering is the main problem you may encounter. The mirliton needs very little water the first several weeks because it comes with its own water source–the fruit. You should initially thoroughly water it and leave it alone for some time so you don’t drown the roots. The only way the container will lose water is through evapotranspiration—by natural evaporation of the soil and loss of small amounts of water through the leaves (transpiration). 

 

The best way to check the soil moisture is the bamboo skewer stick test. It works better than any expensive electronic tester. Insert and withdraw the skewer quickly and visually examine it. It will provide you with a graduated reading–each particle of soil represents the available moisture at that specific level. The bottom of the stake will show the moisture at the deepest level. Feel the skewer with your fingers to get a feel for moisture levels. Then leave the stick out to dry for the next test. 

 

When you move the plant outside, it may lose moisture and need to me monitored more regularly. Here’s the quick and simple video: bit.ly/3w6vJ8o

How To Grow A New Mirliton Seed

by | Oct 14, 2022 | ,

1. If your mirliton has not sprouted, (fig. 1) place it horizontally in the warmest room of your house. At 75 degrees, the mirliton should begin to sprout in 2-6 weeks.

Fig. 1. Unsprouted mirlitons.

2. If your mirliton has already begun to sprout (tongue sticking out) (fig. 2), you are ready to overwinter it to help it develop a root ball.

Fig. 2. Sprout first emerges (above) and shoots extending (below). These are ready to plant.

3. Over-wintering: Once your mirliton is sprouted, plant the whole fruit at a 45-degree angle about 2/3 of the way down with the sprouting end down in a 3-gallon container filled with good potting soil (fig. 3). Water thoroughly the first time. Mirlitons don’t need much water during the overwintering. Here’s how to use a bamboo skewer to test soil moisture. Or you lift the container slightly every few days to gauge if the soil is drying out, and only water if it is noticeably light. David Hubbell has an excellent video on overwintering a mirliton here.

Fig. 3. Sprout planted “sprouting end down” at 45-degree angle with about 2/3 underground in a 3-gallon container.

4. Trellising: Construct a short trellis to support the vine as it grows. For the trellis, use either 24” tomato stakes with a yarn lattice or a small tomato cage (fig. 4). You can prune it back for months to keep it compact, and that won’t hurt the vine. The goal is to develop a good root ball.

5. Transplanting: When the possibility of a spring frost passes, you can transplant it into the ground. See Mirliton.Org for instructions on building a grow site and general procedures for watering, fertilization, shading, and plant pests and diseases.  Click here for Mirliton.Org to find answers to all your Mirliton growing questions. Join the national mirliton gardeners Facebook Group and post questions and follow the progress of other Mirliton gardeners here.

Squirrel Repeller That Works

by | Sep 2, 2022 | ,

Meet The Squirrelator

Well, it doesn’t eliminate them, but it does scare them off, and anyone who has ever grown mirlitons knows that squirrels eat the vine endings and steal the fruit.  What to do?  A wise old extension agent in Mississippi once said, “If there are 100 cures for something, probably none of them work.”  I tried a 100 for squirrels: CDs, noise repellers, and cayenne on the bird seed (the cajun squirrels loved it). None of them worked.  This motion-activated sprinkler shoots a short burst of water in an arc over your vine.  

David Hubbell tested it for the last two years —complete with a game camera that he used to monitor it. The thing works. It is based on the simple principle: Did you ever see a squirrel dancing in the rain?

They work for other crops and will also keep your neighbors from pilfering your garden at night.

It’s available at most online stores, but here’s the Amazon link.

 

Sprinklers Are Effective Frost Protection for Mirlitons

by | Sep 1, 2022 | ,

Mirliton vine the day after a frost that was protected with a rotary sprinkler. The vine is healthy and ready to produce.

A damaged portion of the same vine that was beyond the reach of the sprinkler.

No one wants to nurse a mirliton for months through droughts, floods, and hurricanes, just to have Jack Frost arrive and kill all your flowers before they can fruit. Sprinklers are the most effective, simplest, and least expensive way to protect mirlitons from an early frost.  Moreover, hot weather is the ideal time to set up your sprinkler and adjust it because you don’t want to be running around getting soaked in freezing weather.

Horticulturalists in the South seldom recommend sprinklers because most home gardeners grow soft-tissue vegetables that ripen long beroe the threat of fall frost. But we can find excellent advice from Canadian experts who have perfected the sprinkler systems to protect strawberries from early Sring frosts. We used their experience to design a simple and effective defense against temperatures down to 38 degrees in the fall.

Spraying water on a plant to warm it up seems counter-intuitive, but it works because of a simple principle; when water evaporates from the leaves, it transfers heat into the plant. And when changes to ice on the surface of a plant, it will add heat to that plant. Frankly, the science baffles me, but if you want to know more about it, click here for the Canadian study. For our purposes, the sprinkler frost-defense steps are simple:
Sprinkler Set Up:
1. Place a rotary sprinkler with a metal spike securely on the ground and connect a garden hose to it.

2. Turn the hose on and adjust the sprinkler and mount so that the stream covers the entire vine. Any sprinkler will do, but it’s best to use an impulse sprinkler that can spray a 180-degree arc so you can cover the entire vine. You may have to angle it up.

3. Secure the metal spike so that it does not move when the water is left on for several hours.

When and How to Use the Sprinkler system:
1. Watch the temperature forecast. If the temperature is predicted to go below 38 degrees that night, turn the sprinkler on at sunset and make sure it covers the entire vine.

2. Normally, the coldest part of the night is 4:00-6:00 a.m, so you can turn off the sprinkler after sunrise if the forecast is for temperatures above 40 degrees during the day.

That’s it. We have tested this system on mirlitons for over 10 years and every time it has worked and saved the vines. In 2012, Leo Jones in Harvey, Louisiana used the sprinkler for only part of his vine– it lived while the rest of the vine died (photo above). In 2019, Renee Lapelrolie also used sprinkler heads on only part of her vine, and again, only the protected portion survived (photo below). Not only can the sprinkler protect the vine in the fall, but during a mild winter, it can be used instead to keep the vine alive for a Spring crop.

Buying a sprinkler:
The Rain Bird impulse sprinkler is the best sprinkler head. You can buy it with the reinforced stake and it can cover a vine 40 feet long. There are other brands available, but the Rain Bird is the only one I have had experience with.
Rain Bird Sprinkler Head With Metal Spike Base click here.

How to Adjust Rain Bird click here.

Canadian strawberry frost-protection instruction publication, click here.

Rene Laperolie’s mirliton vine after the 2019 frost. In the foreground, the sprinkler protected the vine. In the background, the unprotected vine was damaged.

 

Click here to see all posts in Mirliton’s Blog

Recent Posts

Identifying and Managing Anthracnose in Mirlitons (Chayote)

Apr 23, 2023

Anthracnose is a summer disease caused by many fungi, but the pathogen that affects mirlitons is Colletotrichum lagenarium. For the purposes of this article, I will call Colletotrichum lagenarium the “anthracnose fungus. It is a chronic problem with mirlitons and it’s...

What is a Certified Louisiana Heirloom Mirliton?

Apr 9, 2023

Up until about 2020, any mirliton grown in Louisiana was an heirloom mirliton. They were what botanists call a “landrace.” Landraces are domesticated plants that developed over time and adapted to their natural environment and are not the product of human...

Incubating Spring Mirlitons

Apr 1, 2023

Growers normally try to delay mirliton sprouting by putting new fruit in paper bags and storing them somewhere cool. But if you get a winter or spring crop, you may want to get them quickly sprouted so they can be directly planted. Here’s an “incubation” trick that...

Fertilizing Mirlitons

Mar 28, 2023

  There has never been a scientific study for home gardeners on how to best fertilize mirlitons,  so we get to invent the science ourselves.  In the growers guide that I wrote several years ago, I recommended  8-24-24 fertilizer. I don’t advocate that specific...

No More Guesswork In Watering Mirlitons: The Soil Sampler

Mar 6, 2023

      Excessive rains and prolonged droughts make it nearly impossible to know if we have the right soil moisture for mirlitons.  Extremes in soil moisture--too much or too little--can stress the plant and cause diseases. Mirliton growers in Brazil long...

Preparing for the New Mirliton Season

Feb 25, 2023

Select a plant site. The most important thing to keep in mind is that water-saturated soil can drown a young mirliton. Even if your plant survives intense rains, excessive soil moisture later in the summer will stress the plant leading to anthracnose. Choose the best...

How To Water A New Mirliton Seed

Jan 25, 2023

The video at the bottom of this post explains in 60 seconds the simple bamboo skewer stick soil moisture technique that will prevent you from drowning your young mirliton.    As you may know, we recommend that you overwinter your mirliton in a 3-gallon container...

How To Grow A New Mirliton Seed

Oct 14, 2022

1. If your mirliton has not sprouted, (fig. 1) place it horizontally in the warmest room of your house. At 75 degrees, the mirliton should begin to sprout in 2-6 weeks. 2. If your mirliton has already begun to sprout (tongue sticking out) (fig. 2), you are ready to...

Squirrel Repeller That Works

Sep 2, 2022

Meet The Squirrelator Well, it doesn’t eliminate them, but it does scare them off, and anyone who has ever grown mirlitons knows that squirrels eat the vine endings and steal the fruit.  What to do?  A wise old extension agent in Mississippi once said, “If there are...

Sprinklers Are Effective Frost Protection for Mirlitons

Sep 1, 2022

No one wants to nurse a mirliton for months through droughts, floods, and hurricanes, just to have Jack Frost arrive and kill all your flowers before they can fruit. Sprinklers are the most effective, simplest, and least expensive way to protect mirlitons from an...