- Eliminating the Cabbage Worm Naturally
- The Best Ways to Use Baking Soda in Your Garden
- Cabbage Looper Overview
- How To Get Rid Of Cabbage Loopers
- Frequently Asked Questions
- Holes in Cabbage, Broccoli and Kale leaves
- 6 Home Remedies to Get Rid of Cabbage Worms Naturally
- How to Get Rid of Cabbage Worms
- Practice Organic Cabbage Worm Control for a Chemical-Free Garden
- What Cabbage Worm Damage Looks Like
- Cabbage Worm Reproduction
- Natural Enemies of Cabbage Worms
- Organic Cabbage Worm Control
- More Advice on Organic Cabbage Worm Control
Eliminating the Cabbage Worm Naturally
To eliminate the cabbage worms there are several methods:
- Yellow Jackets will eat the worms. This is nature at her best. I bet you didn’t know that Yellow Jackets were good for anything.
- Bacillus Thuringiensis (BT): This is a bacterial pathogen that is used for biological control over larvae. It is widely used by organic growers. I have used it with great ￼￼success. It is safe for plants, other beneficial insects, animals and humans. I apply BT once a week starting as soon as I see the white moths flying around the garden. We continue to spray every week until we see no more moths. If you water the plants over head, it will be washed off and will need to be reapplied. We apply in the afternoon on Thursdays. Then on Friday morning we run the sprinklers and most of the BT gets washed off but we do have very good control and do not reapply until the following Thursday. If you are getting a lot of damage then apply twice a week. BT is available at local nurseries; we use a brand named Dipel.
- Repellant drench: In a blender puree spearmint, green onion, garlic, horseradish, hot peppers, peppercorns and water. Add one tablespoon of liquid soap per quart of puree, spray onto plants.
- Flour Powder: Mix 1⁄2 cup of table salt and 1 cup of flour. Sprinkle onto plants while still moist from the morning dew. This mix will bloat and kill the worms.
- Netting: Netting is available for covering the plants in the cabbage family. If you can keep the moths from laying eggs you will get no damaging worms. The plant can grow the entire season under the netting without any loss of crops.
- Diatomaceous earth: Diatomaceous earth is ground up fossilized sea shells. Diatomaceous earth will puncture soft bodied insects and they will dehydrate and die. Local nurseries should carry diatomaceous earth.
- Garlic oil spray: Mince one bulb of garlic and soak in two teaspoons of mineral oil for 24 hours. Next, mix 2 cups of water with one tablespoon liquid soap then add garlic mix to water and soap, mix thoroughly. Strain out garlic and place into a jar for storage, this will be your concentrate. Use one to two tablespoons of garlic oil concentrate to two cups water, then spray plants covering all leaf surfaces. Use for control over aphids, cabbage loopers, earwigs, June bugs, leaf hoppers, squash bugs, and whiteflies.
- Caterpillar deterrent citrus spray: Caterpillars don’t like the taste of citrus; its bitter chemicals run the caterpillars off. To make a citrus spray, grind up the rinds and seeds of any citrus fruit (oranges, lemons, limes or grapefruit). Soak overnight in two cups of water. Strain out the pulp; add two teaspoons liquid soap to mix.
Spray on plants. If you are observant and watch the skies for the moths and then check your plants for the worms, it is easy to see the cycle of the moths taking place. Then you can disrupt the cycle with a spray or manually removing the worms by hand. Observation, identification and a little knowledge will make your organic garden a success. By the way, if you cook your broccoli with the worms on it, they usually float the top of the pot where you can skim them out of the boiling water. I am sure that I have eaten a few without knowing it and I am still alive (more protein for me!)
The Best Ways to Use Baking Soda in Your Garden
Baking soda is a great ingredient for your home and garden. It’s very simple to use, inexpensive and widely available, so it’s great to know how to use it. You probably know how to use it in your kitchen, but it also comes in handy when it comes to other things, such as green cleaning and keeping your garden healthy and pest-free.
Here are some great uses for baking soda you can try:
Preventing Powdery Mildew
Baking soda can be used to get rid of powdery mildew. Powdery mildew is a major problem for many plants, especially impatiens, lilacs, zinnias, squash and cucumber. Many other plants can suffer from it, too, so it’s good to know how to control it. To make an effective spray against powdery mildew, mix 1 tablespoon of baking soda with 1 tablespoon of vegetable oil, 1 tablespoon of dishwashing liquid and 1 tablespoon of vegetable oil. Mix these ingredients together and use the mixture once per week to spray your plants. It’s best to use it on overcast days to ensure that the foliage isn’t burned.
You can use baking soda to make a very effective, non-toxic fungicide. This organic fungicide comes in handy in your garden and it will help you keep your plants strong and healthy. To make this fungicide, mix 4 teaspoons of baking soda with 1 gallon of water. You can use this mix on roses to treat them for black spot fungus. Another good use in on grapes and vines to get rid of fungus when the fruit begins to grow.
Weeds are a major problem in any garden. It’s very difficult to get rid of them and they keep coming back and back. While baking soda can’t make them magically disappear, it can be used to discourage weeds and to control them in your garden. To make an effective remedy, simply sweep or pour baking soda in a thick layer into the cracks of your sidewalk and patios. The baking soda is effective in killing smaller weeds and preventing new ones from appearing.
Get Rid of Cabbage Worms
Another thing you can do with baking soda is to control cabbage worms in your garden. Mix equal parts baking soda and flour. Dust plants infected by cabbage worms (cabbage, kale, broccoli, etc.) This mix is effective in killing them.
Get Rid of Gnats
Baking soda can be used to get rid of gnats in soil and fungus on leaves. To make an effective mixture against this problem, take 4 teaspoons of baking soda, 1 teaspoon of biodegradable soap and 1 gallon of water. Mix everything together and spray the affected foliage as well as soil.
Get Rid of Crabgrass
To get rid of crabgrass, simply wet and pour baking soda on the weed. The crabgrass should start dying in a few says. When pouring baking soda, make sure not to apply it on your grass because it can burn it.
Baking soda is an effective cleaner you can sue to cleanse and sanitize your hands. A long day in the garden makes you hands very messy and dirty, and a regular soap just can’t clean all of it. To clean your hands fully, use baking soda. Simply rub and scrub wet hands with baking soda and rinse.
Photo credit: Seryo via photopin cc
There’s something crawling along the leaves of your arugula, and it looks like a little inchworm. It’s green, and it is snacking as it goes, leaving holes throughout your plants. There’s another on your cabbage, and another one on your radish leaves. What’s going on here?
You have just discovered the cabbage looper in your garden, and if you don’t hurry, they will eat it before you ever have the chance to taste it yourself. So today, I’m going to tell you how to eradicate this moth and its inchworm-like offspring from your yard, and hopefully you will be able to rescue your plants!
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Good Products To Eliminate Cabbage Loopers:
- BT Kurstaki
- Garden Dust
- Trichogramma Wasps
- Spinosad Spray
- Diatomaceous Earth
Cabbage Looper Overview
|Common Name(s)||Cabbage looper, Cabbage moth, Ni moth|
|Scientific Name(s)||Trichoplusia ni|
|Origin||North America, Africa, Europe, Asia, Australia|
|Plants Affected||Prefer plants with natural glucosinolates/glucosides. These plants include cabbage, kale, broccoli, cauliflower, collards, turnips, radishes, mustard greens, and many more. Also can impact beets, melons, some beans, celery, cucumbers, parsnips, peas, peppers, potatoes, spinach, squash, lettuce, thyme, tomatoes, and other vegetable crops.|
|Common Remedies||Handpicking eggs from plants, spraying with Bacillus thuringiensis var. Kurstaki (BT) or natural oil sprays such as garlic oil, introducing or encouraging their natural predators, spreading diatomaceous earth, using cabbage netting to prevent egg-laying.|
Types of Cabbage Loopers
There are other moth or butterfly insects from the Lepidoptera order which are commonly confused with cabbage loopers. These include the cabbage worm (Pieris rapae or Pieris brassicae spp.), the cabbage moth (Mamestra brassicae), the cabbage webworm (Hellula undalis), the orange tip butterfly (Anthocharis cardamines), and the diamondback moth (Plutella xylostella or Plutella maculipennis). Their life cycles and reproduction may be different from the cabbage looper, but they tend to attack similar plants, and often can be eliminated in similar ways.
But for this particular piece, we’re going to focus on the actual cabbage looper, Trichoplusia ni.
Trichoplusia ni, ‘Cabbage Looper’, ‘Cabbage Moth’, ‘Ni Moth’
The cabbage looper (Trichoplusia ni) in its caterpillar and moth state. Source: ajmatthehiddenhouse for moth and Jaume Torán for the caterpillar.
The term “looper” derives from the way the looper caterpillar crawls. Much like an inchworm, it hunches itself up in an arched or looped shape and then propels itself forward. Its scientific name and the term “Ni moth” both come from a pattern common on the wing of the adult brown moth, which resembles the lowercase Greek letter ‘ni’. The reference to cabbage originates with the caterpillar’s fondness for brassicaceae plants.
It is a voracious feeder in its larval or caterpillar state, and primarily consumes leaf greens rather than stems or veins. It can bore into some vegetables like cabbage or cauliflower, leaving waste behind that renders the plant inedible for humans. And it can quickly devour your vegetable garden.
Life Cycle of Cabbage Loopers
Life cycle of the cabbage looper. Source
An adult cabbage looper moth lays multiple pale yellow, round eggs on each plant, both on the tops and bottoms of the leaves chosen. Each female can lay between 300-600 eggs in the 10-12 day adult lifespan. These eggs will hatch in 3-10 days.
The emerging caterpillars are pale white, but gradually turn green with yellowish stripes along their back. They also start out looking somewhat hairy, but gradually lose these hairy spines as they mature. Over the 3-4 week larval stage, they grow and mature, going through color shifts and moulting stages, and it is during this larval stage that they consume vast amounts of leafy matter.
They then form a pupa or cocoon, and somewhere between 4-12 days later they will emerge as full-grown adult, semi-nocturnal moths. In warmer temperatures, the pupal stage is much more rapid. They are considered semi-nocturnal because they will sometimes emerge at or just before dusk to mate and feed, but they are far more active during the nighttime hours.
Common Habitats for Cabbage Loopers
Like cabbage worms, cabbage loopers live where their food is, and that means that they can turn up nearly anywhere where food for humans is grown. However, while their diet is incredibly wide, they tend to prefer brassica-species plants to lay their eggs on due to the high glucosinolate content. They lay their eggs on both the top and bottom of the leaves of their chosen host plant.
What Do Cabbage Loopers Eat?
Cabbage loopers prefer plants which produce natural glucosinolates or glucosides, and that includes nearly every cruciferous food plant. While I provided a short list in the overview, here’s a more extensive list of edible cruciferous plants which cabbage loopers prefer, both for egg-laying and for feeding purposes:
- Bok choy
- Napa cabbage
- Garden cress
- Brussels sprouts
- Collard greens
- Savoy cabbage
- Broccoli romanesco
- Broccoli rabe
- Choy sum
- Cime di rapa
- Gai lan (Chinese broccoli)
- Mustard greens (white, Indian, Ethiopian and black mustards)
Cruciferous vegetables are not the only targets of cabbage looper caterpillars. They are also quite willing to munch on beets, cantaloupe, celery, cucumbers, lima beans, lettuce, parsnips, peanuts, peas, peppers, potatoes, snap beans, spinach, soybeans, squash, sweet potatoes, thyme, tomatoes, and watermelon.
As you can see, these little inchworms are destructive… very, very destructive. And they are not picky eaters, so you have to destroy them as quickly as you find them.
How To Get Rid Of Cabbage Loopers
Figuring out how to get rid of cabbage worms and cabbage loopers is surprisingly similar, as is eliminating many other forms of caterpillar. Let’s look at some of the most common options to figure out what you should do.
Organic Cabbage Looper Control
The first step in cabbage looper control is to try to eliminate eggs when you find them. As they are common on both the top and bottom of the leaves, it can be easier to discover a problem with loopers than with other cabbage worms. Hand-pick the eggs off the leaves while wearing gloves, and drown the eggs in soapy water or crush them to prevent hatching.
By far, the most popular way to eliminate cabbage loopers is by using Bacillus thuringiensis var. kurstaki (also referred to as BT or BTK), a bacteria which creates poison in the looper’s gut after it’s consumed. This is available as both a foliar spray or as a fine dust, and both work quite well to eliminate most caterpillars that prey on produce, including looper caterpillars. However, it should be noted that in some very limited conditions (primarily greenhouse conditions, where only the strongest of the species tends to survive), there have been cases of loopers who appear to be BT-resistant. This has not shown up in outdoor conditions, and it is a fairly uncommon occurrence.
Organic insecticides such as spinosad or pyrethrin are also quite effective against any of the caterpillar species, but they must be handled with caution. These present a very small danger if inhaled during spraying, and you should work with gloves on to keep these insecticides off your skin.
Diatomaceous earth powder is another popular method to control the spread of caterpillars and other insects. Made of crushed shell, the food-grade diatomaceous earth can be spread on all parts of the plant. It is not harmful to humans or larger animals like pets, but to insects, it’s like glass… it cuts their soft skin and causes them to dehydrate and die.
Environmental Cabbage Looper Control
Using parasitic insects such as Trichogramma wasps to eliminate cabbage loopers has proved to be incredibly effective. There are some parasitic flies that also work quite well. Many varieties of birds, both wild and domesticated, will eat cabbage loopers. Among them are house sparrows, skylarks, and domesticated fowl such as chickens, turkeys, and ducks.
Preventing Cabbage Loopers
When looking at how to get rid of caterpillars naturally, one of the best ways that I’ve discovered is to keep them from reaching the plants at all. If you use a floating row cover of fine nylon mesh over your plants, it prevents the cabbage looper moth from laying their eggs on it entirely.
Another option is to use a garlic spray that discourages the butterflies from laying eggs on your plants. You can buy garlic oil sprays, but you can also make your own. This works for June bugs, squash bugs, cabbage worms and cabbage loopers, aphids, and a variety of other insects. Adding a little mint or neem oil to this can be beneficial, too.
Caterpillars also don’t like citrus, so you can make a citrus repellent. Grind up the rinds and seeds of any type of citrus fruit. Soak the ground citrus parts in 2 cups of water overnight, then strain out the pulp. Add 2 teaspoons of dish soap to this and mix thoroughly. Spray all of the plant’s surfaces with that.
Finally, something like neem oil may be a good choice. Neem oil helps to smother the eggs when sprayed onto them, preventing them from hatching. It also acts like a growth retardant, and while it does not completely repel cabbage loopers, it does make the leaves taste bitter to them, which slows the rate at which they consume the plants.
Frequently Asked Questions
Q: Do cabbage loopers eat anything other than edible plants?
A: Unfortunately, yes. These voracious little critters also happily munch on chrysanthemums, hollyhocks, snapdragons, sweetpeas, other brassicaceae family members like alyssum or lunaria, and commercial crops like cotton and tobacco. While it’s less of a concern for them to snack on inedibles, they can still wreak havoc on your ornamentals if they’re left alone. They can also spread from these plants to your edible garden, so keep a watchful eye out for them.
Q: I’ve read that you can salt cabbage loopers to kill them. Does this work?
A: While you can use salt to dehydrate cabbage loopers and slowly kill them, it’s just not as effective as solutions like BT or diatomaceous earth. To be honest, diatomaceous earth is done in a very similar fashion, but as it’s microparticles that act like little knives to the super-soft skin of cabbage loopers (all while not hurting us or our pets at all), it actually is far more effective. Salt also has potential negative impacts on your garden, especially if it builds up over time in your beds. So I don’t recommend using salt in lieu of one of the other options mentioned above.
When you have cabbage loopers, a pinch of prevention is truly worth a pound of cure… or at least a pound of cabbage. So I hope I’ve helped you find the right solution to eradicate these voracious little moth larvae from your prized produce. Have you ever had the war against cabbage loopers before, and did you reign supreme? Let me know in the comments!
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Holes in Cabbage, Broccoli and Kale leaves
Have you noticed those beautiful white butterflies flitting across your garden? Lovely to look at, but what they leave behind is a problem for gardeners.
The larvae of this butterfly as well as the diamondback moth and cabbage looper eat holes in the leaves of cabbage, broccoli, kale, collards and their relatives.
Nature helps control these pests. Parasitic wasps, ground beetles, soldier bugs and lacewings are all natural predators of these insects. You will need to tolerate a little damage and avoid using pesticides in your garden so these good guys will move in and help control the pests.
Regularly check along the stems and between leaves for the gelatinous eggs and green caterpillars. Destroy whatever you find.
Or try the environmentally-friendly Bacillus thuringiensis (Bt) sold as Dipel or Thuricide. The Bacillus thuringiensis, known as Bt, bacteria kills only true caterpillars and is safe for people, pets, wildlife and other types of insects.
A bit more information: Prevent the damage by covering these plants with a floating row cover sold as ReeMay, Harvest Guard or Grass Fast. These polypropylene fabrics allow air, light and water through, but prevent the butterflies and moths from laying their eggs on the plants. Cover the planting with the fabric anchoring the edges tight to the soil with stones, board or other heavy items. Leave enough slack for the plants to grow. Simple and eco-friendly.
6 Home Remedies to Get Rid of Cabbage Worms Naturally
Cabbage worms have to be dealt with as soon as they are spotted in a garden. Here are some home remedies you can try to get rid of the cabbage worms.
How to Get Rid of Cabbage Worms
1. Apply Diatomaceous Earth
Get some food-grade diatomaceous earth and sprinkle it on plants where cabbage worms are spotted. The diatomaceous earth powder will kill cabbage worms by piercing their bodies.
2. Set up a Netting Barrier
Cabbage moths and butterflies may lay eggs a couple of times during the year. During these times, you should set up row barriers or netting barriers across your garden to prevent the adults from laying their eggs. No eggs, no cabbage worm problems.
3. Dust Leaves with Cornmeal
You could kill the cabbage worms by dusting the affected plants with cornmeal. The caterpillars with eat the cornmeal, swell up, and eventually die. Original all-purpose flour may also work.
4. Apply Companion Planting
Grow pest-repelling plants (e.g. thyme, mint) next to your susceptible plants. This could discourage the adult butterflies and moths from laying eggs on your valuable garden crop.
5. Make a Natural Repellent Spray
There are a number of natural ingredients, such as garlic and cayenne pepper, that may deter cabbage worms. Blend these ingredients with water to create the repellent then use a spray to apply it on the undersides of leaves.
6. Introduce Beneficial Insects
A sustainable approach to getting rid of cabbage worms is by introducing natural predators to the garden. This may include spiders, praying mantis, and ground beetles. In addition to these insects, you may also want to attract other natural predators such as birds and geckos.
Other Pest Control Guides
- How To Get Rid Of Bed Bugs
- How To Get Rid Of Dust Mites
- How To Get Rid Of Flying Termites
Sam Choan is the Founder of Organic Lesson. He started this site to share tips on using natural remedies at home when such options are available.
for Cabbage Worms
Now common throughout the United States, the imported cabbage worm (Pieris rapae) does great damage to brassica and other cabbage-family crops in fields and gardens where it gains a foothold. Although the larvae of this garden pest moves sluggishly, it is extremely destructive, especially later in the growing season when populations can build significantly.
The imported cabbageworm (1-1/4 inch long) is velvety green in color and has many short fine hairs and faint yellow strips down its side and back. It’s five sets of pro-legs are easily visible. Adults are white or pale yellow butterflies (1-2 inch wingspan) with three or four black spots on their wings. They are frequently noticed fluttering about the garden from early spring to late fall.
Adult females emerge in early spring after over wintering as green pupae. They lay up to 200 tiny yellow eggs on host plants, usually on the undersides of leaves. These hatch in 7 or more days (depending on temperature) into young larvae caterpillars. The larvae feed heavily for 15 or more days, then pupate on lower leaf surfaces or nearby garden objects. During late spring and summer, the worm pupates for 10 days before a new generation of butterflies emerges. There are 3 to 5 overlapping generations each year, as many as 8 in warmer areas.
In the larval stage, cabbage worms will feed on the surface layer of leaves, leaving behind a a translucent, tissue-like scars. As they grow, they chew large, irregular holes usually beginning on the outside leaves of cabbage and other cole and mustard crops (broccoli, cauliflower, kale, turnip, radish). As the worm feeds, it commonly bores into the center of cabbage heads contaminating them with its fecal pellets. The dark-green pellets can also be found in the crook of leaves near the stem.
The imported cabbage worm is one of many worms that attack garden plants. Luckily, control tactics aimed at a particular worm, be they loopers, army worms, cut worms or diamond back moths, are usually effective against all.
- This insect has many natural enemies, including predatory beetles, spiders, yellow jackets, green lacewing and parasitic wasps. Birds also favor cabbage worms. Make sure your garden welcomes these creatures. And don’t use chemical sprays that might harm or destroy these natural predators.
- Protect plants with floating row covers to prevent adults from laying eggs.
- Use pheromone traps to determine the main flight period for moths.
- Release trichogramma wasps to destroy eggs.
- Predator wasps of various sorts, most indigenous to your garden, will seek-out the eggs of all types of worms. Help protect them by using something other than indiscriminate chemical pesticides.
- Herbalists report that moths are discouraged from laying eggs on cabbage sprayed with tansy oil or a strongly brewed tansy tea (because of the volatile oils it contains, tansy teas can be dangerous to humans, especially when consumed in quantity, and should be avoided; instead use it in your garden). Planting tansy near your cabbage crops can also discourage them. In an example of the two-way street nature of companion planting, tansy planted near cabbage does surprisingly well.
- As soon as damage is noticed (large irregular holes in leaves, fecal pellets on plants and ground), begin handpicking caterpillars and destroying them.
- Chickens can be thorough pickers of cabbage worms. Ducks, too. Of course, they might also eat things you don’t want them to, especially early in the season when plants are still small. Wait until your plants are peck-able size and you’re sure you have a pest problem before unleashing the clucks and the quacks.
- Botanical insecticides — derived from plants which have insecticidal properties — have fewer harmful side effects and break down more quickly in the environment than synthetic chemicals. However, they are still toxic and should only be used after other least-toxic options have been tried.
- Once worms are apparent, apply Garden Dust (Bt-kurstaki) to leaves where they’re seen. This naturally occurring soil bacteria, listed for organic use by the Organic Materials Review Institute, will take out the worms as they feed.
- Spinosad, the active ingredient in Monterey Garden Insect Spray is made from fermentation. It doesn’t persist in the environment — crops are ready for harvest a day after application, and is a good substitute for Bt-kurstaki dusts.
- To prevent overwintering pupae from emerging as adults in early spring, till under all garden debris to which they might attach. In places with milder winters, it may be necessary to remove the debris all together. Pay special attention to plants of the mustard family. They’re a favorite place for cabbage worm pupae to spend the winter.
- Worms will also retreat to garden margins and borders. Keep them clean and short to prevent overwintering there.
Practice Organic Cabbage Worm Control for a Chemical-Free Garden
What Cabbage Worm Damage Looks Like
Velvety green imported cabbage worms eat plant leaves, and can often be detected by the trail of dark frass (excrement) they leave behind. If you see dark green to brown frass near tender new leaves, a cabbage worm is hiding nearby. As plants approach maturity, imported cabbage worms may bore into cabbage heads or infest the undersides of broccoli or cauliflower crowns where they are impossible to see.
Cabbage loopers often feed on leaf undersides when young, and only larger individuals are likely to be caught chewing holes in leaves. Like imported cabbage worms, cabbage loopers sometimes discover great food and shelter in growing heads of broccoli, cauliflower and cabbage. It is not unusual to find imported cabbage worms and cabbage loopers feeding on the same plants.
Because of their small size, diamondback moth larvae stay on leaf undersides, where they rasp away leaf tissues as they feed, creating translucent patches between leaf veins that eventually turn brown.
Cabbage Worm Reproduction
The imported cabbage worm life cycle takes three to six weeks, and goes faster in warm weather. Adult butterflies lay single tiny whitish eggs on leaf undersides, which become yellowish within a couple of days and hatch in about a week. A single adult female can lay 300 to 400 eggs in her 3-week lifetime. The tiny green larvae begin eating as soon as they hatch, and devour plant foliage continuously for about 15 days. The caterpillar then morphs into a pupae, which may be found attached to plants in the summer, or to another plant or nearby object. In summer, pupation lasts only seven days, but cabbage worms also overwinter as pupae, emerging in spring as energetic white butterflies.
Cabbage looper adults fly at dusk starting in late spring. A female may lay more than 500 eggs in her short, 12-day lifespan. Scattered on leaf undersides, yellowish eggs hatch in a few days, and the tiny green worms begin feeding. After about three weeks, the loopers wrap themselves in the cocoon-like pupal case. A new adult emerges four to seven days later.
Diamondback moth adults overwinter only where winters are mild, but south winds blow them northward in late spring. In most gardens they do not cause noticeable damage in spring, and are more likely to be cabbage pests in late summer or fall. Adult females lay about 150 eggs over a two week period, and about a month is needed for a new generation to pass.
Natural Enemies of Cabbage Worms
Numerous natural predators attack all three types of cabbage worms, and occasionally they may provide adequate control. General predators include paper wasps, yellow jacket wasps, shield bugs, and insect-eating birds, including chickens, ducks and guinea fowl. Dead imported cabbage worms with clusters of tiny white cocoons attached are the work of beneficial braconid wasps. In some areas parasitic tachinid flies are more important than wasps in controlling these cabbage pests.
Organic Cabbage Worm Control
In a small garden, you can get good cabbage worm control by checking plants regularly and handpicking cabbage worms as soon as you see them or the frass they leave behind. Chickens consider all types of cabbage worms to be great delicacies; you can even dry the collected caterpillars in the sun for feeding to chickens in winter.
If you often see numerous imported cabbage worms and cabbage loopers in spring, keep plants covered with row cover to prevent egg laying by adults. Two biological pesticides, Bt and spinosad, give excellent cabbage worm control when applied between rains. Bt is less likely to interfere with the work of other beneficial insects compared to spinosad. Organic pesticides are often needed in late summer to protect fall cabbage and broccoli from serious infestation and controls cabbage worms that are hiding among the growing florets. A single treatment with Bt two weeks before harvest can make a huge difference in the quality of cabbage and broccoli.
More Advice on Organic Cabbage Worm Control
Red-leafed varieties of cabbage and kohlrabi are less preferred by cabbage worms, probably because they provide poor camouflage.
You can increase the number of paper wasps that patrol your garden by hanging bottomless birdhouses nearby, or simply use small wooden boxes with no bottoms. They make excellent nesting sites.
Grow plenty of flowers and blooming herbs to provide a continuous supply of nectar for beneficial insects. Provide perches to increase how many cabbage pests are snapped up by birds.
More information on organic cabbage worm control is available from Ohio State, University of California, University of Maryland.