by Lance Hill | Aug 10, 2022 | How To, Mirliton
I have researched how to manage squash vine borers and there is remarkably little scientific research that will help the home gardener. Big commercial growers use a chemical drench, but that’s no help for organic gardeners. I have heard everything from row covers to wrapping the base of plants with aluminum foil. Maybe they work, but I have not found any rigorously controlled studies of the methods.
Foliar spraying of BT (Bacillus thuringiensis) appears to be the most effective way to manage squash vine borers. There is persuasive research that BT works on cucurbits like mirlitons (chayote). Start spraying the vines early in the spring and continue throughout the season (don’t mix with oils because they can kill the vine in hot weather). Some people inject the BT into the vine with syringes, but this will not work because larvae don’t consume BT and it will only kill the larvae if it reaches their gut.
Click here for the best article I found on BT for managing vine borers.
Click here to read about how it is safe for humans to use on crops.
by Lance Hill | Aug 7, 2022 | How To, Mirliton
Leaffooted stink bugs have invaded our mirliton gardens and orchards. They feed on flowers and fruit, killing flowers and injecting enzymes and diseases into the fruits that ruin the flavors or bruise them. And, yes, they stink.
There are several leaffooted stink bug species in the Gulf Coast South, but the principal culprit is a new arrival Leptoglossus zonatus (Dallas), widely known as the “western leaffooted bug”. They are with us year-round and overwinter in weeds and tree bark. They emerge in the spring as “nymphs” (immature bugs) and go through five stages called instars. We will concentrate on two of the stages that gardeners are most likely to see on their vines: nymphs and mature bugs.
How to Identify:
Identifying leaffooted bugs is tricky since they look almost identical to assassin bugs, which are beneficial insects that eat bad bugs and don’t damage plants. Because they are physically similar, sometimes people try to distinguish them based on the different markings of the two species. That will work for mature stink bugs, but markings are not always useful for nymphs because they don’t appear in all instars. For example, the characteristic leaf-like “flared” back legs don’t appear in all stages of a leaffooted bug’s life (see the two photos below of nymphs with no flared legs on a mirliton fruit and flowers). A simpler and more reliable way to identify stink bugs is by behavior:
Nymph stage: For most of the growing season, stink bug nymphs are easily identified by their aggregating (swarming) behavior. They like to aggregate into small gangs and search for young flowers and immature fruit. In contrast, assassin bugs are solitary hunters, even as nymphs, and won’t be found in gangs. So don’t t worry about markings; if they behave like a gang, then they are stink bugs. You can control them at this early stage with regular spraying throughout the growing season with insecticidal soap or organic pesticides such as Bee Safe Organicide that won’t harm bees.
Immature nymph leaffooted bugs in characteristic swarming behavior. Note that at this stage, they don’t have the flared back legs.
Stink bug nymph feeding on immature flowers (also, no flared back legs)
Stink bug damage to young mirliton fruit. Note exudate emerging on top right in a bubble.
Mature stage. Adults can’t be sprayed away; they have a hard exoskeletal structure that protects them from topical insecticides. They are also solitary foragers like assassin bugs, but they are easily identified because they are vegetarians. In contrast, assassin bugs only eat other bugs while leaffooted bugs feed on flowers and fruits. They have to be removed by hand by picking them off by hand, sucking them up with a portable vacuum, or catching them with a butterfly net.
I prefer the hand vacuum (with a homemade 1/2 inch diameter PVC extension—see below) because stink bugs are highly aware and will instantly dash away at the sight of a large extension. Plus, you are less likely to damage flowers. The contents of the vacuum can be emptied into a pail of water with insecticide. Leaffooted bugs and assassin bugs are quick and elusive and difficult to identify as adults. If you accidentally removed an assassin bug, it will not hurt the species since they forage everywhere, unlike leaffooted bugs that target your vegetables and fruits.
Mature leaffooted bug. Note white mark across the back and the well-developed flared “leaves” on the back legs.
Monitor For Stinkbugs Daily:
The key to managing pests is knowing which ones are on your vine because early intervention is critical. Closely scout your vine every day, top and bottoms of leaves, and use sticky yellow insect traps to collect specimens. Click here for sticky traps.
Click here for an excellent recently updated fact sheet on Leptoglossus zonatus (Dallas)
The Dewalt 20v. portable vacuum has the power to vacuum up large bugs and can be used for household and automotive cleaning. An accessory kit is available and that will allow you to fit it with a 1/2-inch PVC pipe extension.
by Lance Hill | Jul 17, 2022 | How To, Mirliton
Powdery Mildew on a leaf in the early stages of the infection. The best time to diagnose powdery mildew is in the early stage on mostly green leaves. It starts as irregular pale yellow blotches that combine until the whole leaf is yellow.
Powdery mildew is a troublesome plant disease but, thankfully, never lethal. It’s largely a Spring disease because it thrives in cool, damp weather, so it’s the first disease you will see in the mirliton growth cycle. The good news is that there’s an effective organic fungicide that manages the disease.
The most visible signs of advanced powdery mildew are bright yellow leaves. But chlorotic (yellowing) leaves can be also caused by overwatering or anthracnose. The most accurate way to identify powdery mildew is to examine the seemingly healthy green leaves near yellowing ones. Look for the early signs of mildew are irregular faded yellow blotches like in the photo above. That is the fungus forming little colonies that will eventually into bright yellow leaves.
If you find signs of the disease, there is a highly effective organic fungicide that can control it: potassium bicarbonate. It can completely eradicate the disease in three weeks and works on downy mildew as well.
We recommend L.D. Carlson’s potassium bicarbonate because the manufacturer has verified with a Certificate of Authority (COA) that it is at least 99.5% pure. It’s generally sold in one-pound quantities, which is more than you will need, but it has a long shelf life, and you can share it with other growers. Click here to order online.
L.D. Carlson’s potassium bicarbonate.
If you are using a 99.5% pure potassium bicarbonate product, mix one tablespoon with a gallon of water and shake vigorously. Then spray only in the evening and thoroughly wet the tops and bottoms of all leaves. Apply once a week for three weeks until there are no signs of early infection (faded yellow blotches on green leaves).
For a more thorough article on powdery mildew and mirlitons, see my paper here.
by Lance Hill | Jul 17, 2022 | How To, Mirliton
Sprouting mirliton.
We occasionally get a Spring mirliton crop and decide to gift or sell them to others to grow. You could plant them in small containers and sell them that way, but that would mean that potential growers would have to transplant them into the ground during the full heat of the summer. That would be risky. That’s why we recommend that growers sell their fruit as sprouts as soon as possible after picking them. Sprouts can be safely planted in May-June with a simple shade technique (click here). So how do you expedite sprouting?
Mirlitons sprout (germinate) in response to warm weather. Joseph Boudreaux taught me the simple technique for incubating mirlitons in May: Place them in a warm place outside and they’ll sprout within 10-14 days. It’s best to place them away from the direct sun and inside a container such as a milk crate where varmints can’t get them (squirrels, possums, and rats). As soon as they begin to sprout, you can assure people that they are viable seeds and ready to plant.
by Lance Hill | Jul 12, 2022 | How To, Mirliton
Guttation forming on leaf tips and edges
Your mirliton will tell you every morning how much water its roots are accessing. It is called “guttation.” If there is more than adequate soil moisture available at night, mirlitons will send the excess to the leaves where it will be visible in large droplets on the margins of the leaves. The water exudes from glands at the tip of the leaves. Guttation means the plant has more than enough water; if you don’t see guttation for several days, then it’s probably time to water. Click here for a link to instructional photos of guttation and how to read it (click on each photo for explanations).
by Lance Hill | Jul 12, 2022 | How To, Mirliton
Watering Mirlitons
I could have titled this “How To Water Your Mirliton” but that would be like asking, “How To Care for a Child.” There’s no single answer because each child is different and has different needs at different times in their life. Plants are the same. So this is a set of guidelines instead of rules for watering mirlitons during their three distinct stages in their life cycle.
It used to be said that mirlitons “take care of themselves” and need little care; the increase in hurricanes, floods, and intensive rain days means that is no longer true. Now they need intensive care. No watering technique can remedy a flawed plant site. Mirlitons need quickly draining, well-aerated soil. That means you may have to install drainage (ditches, French drains) in your ground planting; in raised beds, you need lateral exit routes for excess rain, such as side holes or subsurface corrugated pipe. Rapid and wide fluctuations in soil moisture content in your raised bed can stunt growth and hinder flowering and fruiting. These guidelines will generally apply to both planting methods.
Steps to take Before You ever Turn on the Hose:
Get a rain gauge. Place it next to your vine and check it daily. The weather person has no idea how much it rained in your yard—you need to know it for your vine’s health.
Don’t guess about the vine’s water needs. The soil and the leaves will tell you exactly what you need to know if you scout them daily. Learn to read the bamboo stake or soil sampler and the mirliton leaves. They will tell if the vine needs water, and too much water can create a sick vine.
Use a Bamboo Stake or Steel Soil Sampler to gauge soil Moisture: Learn how to use a ½-inch bamboo tomato stake to test soil moisture in the root zone. It will tell you instantly if your vine has too much or too little available moisture. There’s a link at the end of this article to how to read the stake. Or buy a stainless steel soil sampler that allows you see and feel moisture levels beneath the surface (link below)
Check Guttation Daily: Mirlitons will tell you every day if they are quenched or thirsty. Guttation is the droplets of water that form on mirliton leaf edges early in the morning. The presence of guttation means the vine has more than enough available water in the root zone. Three days without guttation mean it probably needs watering. Check the vine first thing in the morning for guttation. Learn to read your mirliton leaves at the link below.
Wilting Does not Mean Water the Vine. A daily wilt in hot weather is normal and healthy mirliton. It’s called “leaf flagging” and it reduces exposure to direct sunlight and toughens the leaves against plant diseases. Watering mirlitons as a reaction to temporary wilt can actually harm the plant. When you see a daytime wilt, wait until the evening and probably see that it recovers.
Never give your vine a shower. That’s a surefire way to start an anthracnose epidemic. The anthracnose pathogens are primarily carried primarily by water through splash-up from the soil or splashed from leaf to leaf. Water gently at ground level with a hose on low, or use drip irrigation.
The Three Stages in the Mirlton Life Cycle:
1. Toddler:
Be careful with the baby. The first impulse when we see a young plant droop is to water our way out of the problem. Don’t do it At the toddler stage, mirlitons are most sensitive to soil moisture issues because their young roots are just emerging. Overwatering is the leading cause of premature death in mirlitons. Prepare for your toddler by installing gentle drip irrigation or an olla. Use the stake and read the leaves daily.
2. Sprawler:
Once the vine is established, it will begin to climb and sprawl. A larger canopy means they need more water. Daily summer showers should provide enough water, but don’t guess–use the stake and read the leaves.
3. Fruiter
The fall is fruiting season and water needs may increase, but use the stake and read the leaves.
Final Thoughts
Watering is not something you simply do to a mirliton vine; it’s something you do with it. It’s a partnership in which both parties have something to say. Listen to your vine.
Bamboo stake instructions here.
Steel Soil Sampler here.
Read the Mirliton Leaves here.
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