Identify, prevent and treat the Cabbage White Butterfly
IDENTIFY AND TREAT CABBAGE WHITE BUTTERFLY
- 1 IDENTIFY AND TREAT CABBAGE WHITE BUTTERFLY
- 2 RECOGNISING CABBAGE BUTTERFLIES AND CATERPILLARS
- 3 LIFECYCLE OF THE CABBAGE WHITE BUTTERFLY
- 4 PREVENTING AND TREATING CABBAGE WHITE BUTTERFLY
- 5 COMMENTS / QUESTIONS LEFT BY OUR READERS
- 6 Tips To Control Cabbage Maggot In The Garden
- 7 What are Cabbage Maggots?
- 8 Symptoms of Cabbage Root Maggot
- 9 How to Get Rid of Cabbage Maggots
- 10 Information About Cabbage Maggot Control
- 11 Identifying Cabbage Maggots
- 12 Cabbage Maggot Control
- 13 Cabbage, Its Allied Companion Plants, and Its Enemy Combatants
- 14 How to get rid of cabbage white butterfly and other garden pests
Although this pest is commonly referred to as the Cabbage White Butterfly it is really at the caterpillar stage that the damage is done.
Without a doubt, prevention measures are the key to success with this pest. If the butterflies get a chance to lay their eggs on your cabbages, cauliflowers, Brussels sprouts, turnips or swedes then your chances of effectively getting rid of them is small indeed.
RECOGNISING CABBAGE BUTTERFLIES AND CATERPILLARS
IDENTIFYING THE CABBAGE WHITE BUTTERFLY
The female butterflies lay eggs twice, sometimes three times in a season which hatch into caterpillars after a couple of weeks. Typically eggs are laid on the underside of leaves and to get an idea of size there would be about 25 on a 5p coin. Eggs tend to be laid 20 or so at a time. The butterflies emerge in April / May time depending on your local weather. The eggs are shown in the picture below.
When the eggs begin to hatch the top of the eggs have black and white top to them which are the young caterpillars emerging.
Finally onto the caterpillars which do all the damage. There are two types, the pale green one and the green and black ones. Identifying them is a bit pointless in reality because any caterpillar on a brassica needs to be removed! However the picture below shows the more common black and green type of caterpillar.
LIFECYCLE OF THE CABBAGE WHITE BUTTERFLY
The last egg laying of the season occurs in late August to September time depending on weather conditions. The eggs are laid on both the under and upper surface of leaves. The caterpillars emerge after a short time and begin to feed on the leaves of plants, typically members of the cabbage family.
When fully fed the caterpillars move away from their source of food and pupate (change into butterflies) on broken bark, fences and similar sites which are higher than the soil surface.
Cabbage white butterflies do not over winter in the ground although the Cabbage moth does. The large whites are unlikely to survive our winter but the small whites butterflies and moths definitely do survive.
PREVENTING AND TREATING CABBAGE WHITE BUTTERFLY
Chemical treatments are discussed below but the primary prevention measure is to cover your cabbages, cauliflowers and Brussels sprouts with some form of barrier to prevent the butterflies getting in. There are several options available which include Enviromesh, non-branded meshes, scaffold debris netting and horticultural fleece.
The principle behind all of them is to provide a covering which prevents insects getting in (including the Cabbage White Butterfly) but at the same time allowing air to circulate, water and light to enter freely. The costs, effectiveness and lifespan of each solution differ wildly so we have a devoted a special page which analyses in detail the pros and cons of various insect protection meshes and netting. The article also describes how to secure the netting to provide maximum protection. Click here for our page on insect mesh netting.
If Cabbage White caterpillars do manage to get onto your plants take action as soon as possible by removing as many as possible by hand. At the same time remove any eggs you see which are normally on the underside of the leaves.
The safest insecticide to use for Cabbage White Butterfly is one which is based on pyrethrum. Stronger chemical sprays include lambda-cyhalothrin. Always read the label of any insecticide for full instructions.
COMMENTS / QUESTIONS LEFT BY OUR READERS
|Date: 23 November 2017||From: Wayne M|
|QUESTION: Hi, i live in Crete, Greece, I’ve been growing my cabbage and cauliflower etc and I’ve seen the butterfly, yes its a pest, I’ve been spraying everything with alverde 24sc for pest control and cabrio duo for diseases, I’ve gota say it really hasn’t done its job and i spray nearly every week. Everything gets watered every 2 or 3 days so nothing dries out but the leaves still wilt. I thought too much sun but where I have everything growing only gets a few good hours. I took pics of the eggs on the leafs etc and some of the damage caused, and the guy in the garden center just told me to use what I’ve been using the alverde and cabrio duo.|
ANSWER: I think no amount of spraying will stop the damage. The only realistic solution is to stop the butterflies getting to the cabbages. And the only way I know of doing that is by netting them
|Date: 14 May 2017||From: Deb|
|QUESTION: Do Cabbage Whites lay their eggs on red cabbage plants? Thanks
ANSWER: It appears that Cabbage whites are colour blind and will lay their eggs on any cabbage they can find irrespective of colour! The only benefit of red cabbages is that it is easier to spot the green caterpillars of the Small White which are light green in colour.
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Tips To Control Cabbage Maggot In The Garden
The cabbage root maggot is responsible for many home gardens suffering a total loss of their root vegetables and cole crops. The control of cabbage maggot is simple but doesn’t need to be done correctly in order to be effective. Keep reading to learn how to get rid of cabbage maggots and their damage from your garden.
What are Cabbage Maggots?
Cabbage root maggots are the larval stage of the cabbage root fly. The cabbage root fly is a small, grey fly that looks like a house fly but more slender. The cabbage root fly will lay its eggs at the base of a plant and when the eggs hatch they become small, white legless worms.
Cabbage root fly eggs can only hatch in cool weather, which is why these pests attack mostly cool weather crops. Most commonly they will attack:
Symptoms of Cabbage Root Maggot
While not a sure sign of cabbage maggots, if the leaves of your plants start to wilt, check the roots of the plant for cabbage root maggots. Their damage to the roots will often cause the leaves to wilt.
Unfortunately, the easiest way to tell if you had cabbage root maggots is after you harvest and the damage to the root crops is visible. The roots will have tunnels or holes in them.
Also, in the early spring, if you see the cabbage root fly around your garden, you can expect that it is laying eggs and that cabbage maggots will be at your plants soon.
How to Get Rid of Cabbage Maggots
It is nearly impossible to control cabbage maggots themselves. Once they are in the roots of your plants, you have little choice but to pull the plants and destroy them in order to try to stop the cabbage root maggots from returning next year.
The only effective control of cabbage root maggots is really cabbage root fly control. When you control the cabbage root fly, you will prevent the maggot from getting into your garden in the first place.
Cabbage root fly control is best done with placing row covers over plants during the spring. This will keep the cabbage root fly from being able to lay their eggs at the base of the plants and stops the cycle.
At this time, there are no effective cabbage root fly insecticides. Your best bet, if you would like to try an insecticide, is to cover the soil around the base of the plants with a powdered insecticide of some kind. However, be aware that these sorts of insecticides aren’t proven to be fully effective at killing the cabbage root fly before it is able to lay its eggs.
Information About Cabbage Maggot Control
Cabbage maggots can wreak havoc on a newly planted patch of cabbage or other cole crop. Cabbage maggot damage can kill seedlings and stunt the growth of more established plants, but with a few preventative steps for cabbage maggot control, you can protect your cabbage from being damaged or killed.
Identifying Cabbage Maggots
Cabbage maggots and cabbage maggot flies are most often seen in cool, wet weather and most commonly affect gardens in the North. The cabbage maggot feeds off the roots of cole crops like:
The cabbage maggot is the larva of the cabbage maggot fly. The larva is small, about ¼-inch long and is white or cream colored. The cabbage maggot fly looks like the common housefly but will have stripes on its body.
Cabbage maggots are most damaging and noticeable on seedlings, but they can affect more mature plants by stunting their growth or causing the leaves of the plant to have a bitter flavor. A seedling or adult plant affected by cabbage maggots may wilt or take on a blue cast to their leaves.
Cabbage Maggot Control
The best control is to prevent cabbage maggots from being laid on the plants in the first place. Covering susceptible plants or growing the plants in row covers will help to prevent the cabbage maggot fly from laying its eggs on the plants. Also, placing yellow buckets of soapy or oily water out near the plants is said to help attract and trap the cabbage maggot flies, as they are attracted to the yellow color and then drown in the water.
If your plants are already infected with cabbage maggots, you can try applying an insecticide to the soil to kill them, but typically, by the time you discover that a plant has cabbage maggots, the damage is extensive enough that pesticide will not save the plant. If this is the case, your best option is to pull up the plant and destroy it. Don’t compost affected plants, as this can give the cabbage maggots a place to overwinter and increases the chances that they will return next year.
If you had a vegetable bed affected by cabbage maggots, you can take steps now to prevent cabbage maggots from returning next year. First, make sure that all dead vegetation is cleared out of the bed in the fall, to reduce the number of places the cabbage maggot can deposit over winter. Till the bed deeply in late fall to help expose and disturb some of the cabbage maggot pupae that may be in the soil. In the spring, rotate the susceptible crops to a new beds and use row covers. Systemic and organic pesticides like neem oil and Spinosad can be applied at regular intervals to help kill any larva that manage to get past other efforts to control the cabbage maggots.
While cabbage maggot damage may ruin your crop of cabbage this year, that’s no reason to allow them to continue to plague your garden. Following a few simple steps cabbage maggot control will help you ensure that this pest does not bother you again.
Cabbage, Its Allied Companion Plants, and Its Enemy Combatants
Companion planting benefits cabbage several ways. It grows well near companion plants and less well near combatant plants. Some plants repel pests that infest cabbage, and others lure them away. There are also plants that act as barriers, making it difficult for pests to reach the plants they infest and plants that attract insects that pollinate your garden or insects that prey on garden pests.
The Character of Companion Plants
Companion plants have other traits that make them good company for cabbage. In general, they have the same preferences when it comes to soil, watering, temperature, and light.
Cabbage likes areas with full sun but cool temperatures. The area should be well-drained at the surface but have nutrient-rich, loamy or sandy soil that retains moisture below the surface. Mulch the soil heavily, and give cabbage 2 inches of water each week. The soil should have a pH of 6.5 or less.
Cabbages companion plants include:
Plants That Control Cabbage Pests
Several plants either repel cabbage’s pests or lure them away.
Plants That Improve the Taste of Cabbage
Some of cabbage’s companion plants improve its flavor.
Plants That Help Cabbage Grow and Be Healthy
Some cabbage companions help it’s growth.
Combatant plants should be planted on opposite sides of your growing space or kept at least 4 feet apart. Cabbage’s combatant plants are:
You would think that broccoli, cauliflower, and cabbage are such closely related siblings that they would grow well together, but they are like selfish, jealous siblings. All three absorb such a substantial amount of the same nutrients from the soil that the soil might not be able to provide enough if these crops are planted together. So, keep them separated so that all three get enough of what they need to be healthy and grow.
Mustard is also related to cabbage. Cabbage and its siblings are all descended from a wild mustard plant. Because they are all related, though, they all attract the same pests. There is an advantage to growing mustard in one area and cabbage in another area, however. The mustard will lure pests away from your cabbage.
Bittercress, a relative of mustard and cabbage which is also known as rocketcress or winter cress, has been shown by research to lure the diamondback moth and the imported cabbage white moth away from crops like cabbage.
In fact, bittercress produces a substance that is toxic to diamondback caterpillars. When they begin to feed on bittercress, they die. Bittercress may or may not be toxic to imported cabbageworms. Only the diamondback moth and its caterpillar were included in the research.
Tomatoes repel the imported cabbageworm, but cabbage still doesn’t like getting close to tomatoes.
Plants That Benefit Your Entire Garden
Nasturtiums attract aphids, flea beetles, and caterpillars. In fact, aphids likely will prefer nasturtiums to anything else growing in your garden.
While marigolds are particularly beneficial to cabbage, they repel nematodes and beetles and may even repel deer. On the other hand, while flea beetles attack several crops, nematodes and some subterranean beetles prey upon cabbage maggots, so take that into consideration when deciding where to plant your marigolds.
Yarrow not only repels insect pests but also adds nutrients to the soil where it grows and gives a boost to the plants growing near it. At the end of the growing season, yarrow can continue its work by contributing to your compost.
Attracting Beneficial Insects With Companion Planting
The plants in and around your garden can help attract beneficial insects as well as acting as lures or repellants for harmful ones.
For example, dill, parsley, carrots, and parsnips attract spiders, ladybeetles or ladybugs, and praying mantises that prey on insect pests for many plants.
In addition, fireflies attack cutworms, but fireflies need a place to rest during the day. Planting shrubs and short trees where they can rest will attract more of them to your garden. Trees and shrubs also attract insect-eating birds.
Keep your shrubs well-trimmed, though. Allowing too much growth provides a sheltered habitat where flea beetles and moths could hide for the winter. Proper pruning lets air flow through the branches, which is healthy for the shrubs but decidedly not healthy for the insects attempting to overwinter there.
How to get rid of cabbage white butterfly and other garden pests
Alan Down takes a look at what gardeners can do to keep the dreaded cabbage white butterfly away
In the next few weeks the white butterflies will cause havoc to vegetable growers unless plants are given protection now. The large and small white butterflies are already flitting here and there, and will be seeking out members of the brassica family on which to lay their eggs very soon.
Perhaps, by the time you read this, some will have already placed their neat little packages on the undersides of your cabbage, sprouts or kale. The cabbage moth can be problematic, eating its way into the heart of your cabbages and become very hard to control.
Making a tent of fine netting over vegetable plants at risk works well but only if there are no holes or gaps near the ground through which the adults can get in. It’s important to allow for your plants getting taller by buying extra insect proof netting. The net can be allowed to drape directly on to the plants but some gardeners prefer to make a simple support structure.
Of course, you could pick caterpillars off your plants but I find that I invariably miss some and this is usually the well camouflaged green caterpillars of the small white butterflies. They avoid detection by resting between feeds along a leaf vein which they very much resemble.
This is where investment in bird feeding pays off. Birds brought into your garden by your regular feeding may remove many of the caterpillars as they grab them to feed their young.
Another approach, and one which takes care of the other major pests that like brassicas as much as we do, is to regularly apply a spray protection coating of garlic to your plants. Application every ten days or so seems to be sufficient but, for plants growing fast, new leaves may need to be protected by shorter intervals between spraying. Of course, these garlic sprays are only needed during the peak season of pest threat and that is usually from now until the end of August. It is important to stress that such garlic sprays do not result in your sprouts or any other crop tasting of garlic.
Obtaining garlic spray can prove tricky, as it is not yet widely available but it is a product that we have been selling and using at Cleeve Nursery for more than five years. Attack from mealy cabbage aphid and white fly can be prevented with regular sprays of garlic and it is unlikely that netting will keep these pests out.
You may wish to go down the biological control route by ordering and having live natural predators delivered fresh to your door. This method uses tiny nematodes that predate the caterpillars. It seems to work better during cool and damper weather periods. It is important to order and apply these at the very first sign of attack. Naturally, this very safe and closely targeted means of control of caterpillars will not give you control of the sap-sucking pest that also can be problematic.
I’ve mentioned sprouts, kale and cabbage as members of the brassica family, but do bear in mind that so too are turnips and swedes, so these will need protection from cabbage white caterpillars too. If you grow the enormous and spectacular perennial Crambe in your flower borders, this will also need protection since it too is a close relation.
If you prefer to use chemicals to control these pests, there are still some pesticides available to use but I would strongly recommend that spraying is only done early in the morning or late in the evening. This will minimise the impact on beneficial insects in your garden. I also recommend adding a little washing up detergent to the spray to act as a wetter. This ensures that you get a better coverage and less run-off wastage of spray since brassicas invariably have waxy almost waterproof leaves. Don’t over-do this and about one drop per two litres of dilute spray is all you need.
At the moment the sprays that are still available for use on edibles include Bayer Sprayday Greenfly Killer, Westland Resolva Bug Killer, Neudorf Bug & Larvae Killer and Bug Clear Gun for Fruit & Veg. When using sprays, always read and stick to the manufacturers recommendations for handling and using these materials.
Alan’s gardening tips for the weekend
Remove the dead flowers from tall perennials such as delphiniums, lupins and foxgloves. This will encourage them to flower again this year.
Fill any gaps in your borders and pots with plants that provide instant colour. There is a large range available from Cleeve Nursery.
If you are having a few friends around for a party in the garden, brighten the place up with a few extra planted pots.
Keep your lawn edges neat by regularly trimming. Inserting plastic or alloy edging support strips will stop the edges becoming ragged.
Check for briar suckers coming from the roots of roses and remove them flush with the roots to avoid getting more.
Vigorous climbers such as clematis, honeysuckle and perennial sweet peas will need tying up again. Support them well and they will repay you well with more blooms.
Vigorous shrubs such as firethorn (pyracantha) will benefit from having over-long shoots pruned back and this will stop them hiding the attractive berries which should have formed on old growth.
Its time to tackle any bindweed that is strangling plants. If it is growing up and through plants pull it aside and treat with New Roundup Weed killer Gel. Alternatively, shield your garden plants with some polythene and spray with a glyphosate based weed killer such as Roundup.
Regular hoeing between plants in borders and in the vegetable patch will keep weeds under control and also reduce drying out of the soil.
Now is a good time to spray thistles, couch grass, Japanese knotgrass, bindweed and other difficult to control perennial weeds. Roundup (or other weedkillers containing glyphosate) is the best material to use and is inactivated when it touches the soil. However, keep it off the leaves and stems of plants you do not want to kill. If the weeds are in among plants you wish to keep use Roundup Weed killer Gel.
Plant butterfly and bee-friendly plants in a warm sunny place. Try buddleja, hebe, wallflowers, sedums, marjoram, mints, aster, solidago (golden rod), heathers, and thyme.
Try one of our Wildlife World butterfly and moth feeders in your garden.
Question: I have 4×1-metre long troughs and would like to have bamboo growing in them. I need height for privacy, so can you advise?
Answer: You can grow bamboo in troughs but it will be more successful if:
Many types of bamboo are suitable but I would recommend Fargesia types as they will produce a dense thicket of canes and have a dense leaf cover.
Alan’s plant of the week
Gaura Rosy Jane
Although Gaura originates from South Africa some varieties are proving to be really quite hardy here in the West Country. This is one of those airy fairy, half-woody, half-herbaceous perennials that look so good at this time of the year.
Vanilla has proven to be particularly resilient coming through this last testing winter with flying colours, and Rosy Jane is a stunner with each petal having a pink margin. The tiny flowers on all are held aloft on tall thin stems that move with every breath of wind and each bloom looks like dancing butterflies. Plant in full sun with good drainage.