Cabbage White Butterfly

We here at Confetti Gardens treasure pollinating insects!

We love growing flowers, herbs and veggies and are big supporters of an organic, non-GMO plant based diet. Let’s live a little more sustainably in making our gardens future-proof and in growing more biodiverse plants that attract wildlife.

This issue is dedicated to the beautiful cabbage white butterfly. As delicate and gorgeous as they are, unfortunately, these insects are not every gardeners’ cup of tea. Let’s dive straight in and see what the buzz is all about…

Happy reading everyone!

Love, from Franzi

@talesfromourcountrygarden

As ecological gardeners, we’re quite happy to welcome pollinators into our gardens. In fact, we’ll even design our gardens with these ever so useful insects in mind. The sight of a simple solitary bee, a fluffy bumblebee or a colourful butterfly in the garden fills our hearts with joy.

That is, until the cabbage white butterfly comes along and you see your brassica harvest eaten before your very eyes. But what can you do? Insecticide isn’t an option, since you’re an organic grower and later, you plan to eat those brassicas yourself. No poison on my plate, thank you very much!

In this issue, we zoom in on this rather humble butterfly and try to understand it better, so we can enjoy both its beauty as well as some lovely bok choy or broccoli. We’ll be giving you tips and tricks to protect your harvest without having to resort to any chemicals whatsoever.

Intrigued? Welcome to the world of the cabbage white!

@frannigoesprint

First of all, let’s get the naming issue out of the way: depending on where you’re situated, you might hear different names: cabbage butterfly, cabbage white (large or small) or even cabbage moth (which it isn’t). All these names refer to one of two closely related species of butterfly; Pieris rapae (the small cabbage white) and Pieris brassicae (the large cabbage white). They look quite similar, although the large cabbage white is, indeed, larger in size and has a black band on the tip of its forewing, which its smaller cousin lacks. There is also the actual cabbage moth (Mamestra brassicae), which has grey/brown wings and white spots.

Not that these differences matter from a gardener’s point of view, since the caterpillars of all three species can almost completely destroy your brassica patch.

The adult butterflies, as well as the moths, feed on nectar and act as important pollinators to many meadow flowers, including dandelions and red clover but will also visit your garden in search of mint and strawberry flowers. They are a crucial link in your garden’s ecosystem and should not be disregarded as a pest or nuisance. In fact, we should be welcoming these helpful pollinators into our gardens.

@joysmaking

They can become a problem though once they start mating.

Cabbage white butterflies are amongst the first butterflies you can see in spring as early as February, as well as one of the last species as late as November, if the weather is mild enough. Adult butterflies can start mating when they are only several days old, giving these butterflies a very long time span to reproduce. Once a male and female have copulated, the female butterfly starts looking for suitable host plants, specifically members of the brassica and mustard families. The eggs are deposited on the ground-facing side of the leaves and after four to eight days, the eggs will hatch. The cabbage moth has a shorter reproduction period only depositing eggs between May and June.

The cabbage white’s eggs are a pale to golden yellow and have typical ridges. The cabbage moth lays similarly ridged, white eggs. All the eggs are deposited in small clusters and out from these tiny eggs, the caterpillars will hatch. The larvae will firstly eat through the egg before voraciously eating their way throughout several life cycle stages

So, this places us in a bit of a conundrum: on the one hand we want to protect the butterflies as the useful pollinators they are, whilst on the other hand we want to protect our vegetable plants against a ‘brassica massacre’.

Useful companion plants for your brassicas: Nasturtiums

@fleurrustique

Well, here are our top tips to handle the cabbage white butterfly in your vegetable garden:

1. Netting

It’s a simple truth: if the butterflies can’t reach the plants, they’ll have to go elsewhere. Make sure you apply ultra-fine netting over the plants leaving no gaps or openings. Leave ample space between the plants themselves and the netting, so the butterflies can’t reach to deposit their eggs through the holes in the netting.

2. Pick them off

A daily check-up of your brassica plants will allow you to pick off the caterpillars and place them elsewhere (a meadow, for example). Make sure to inspect both the top and bottom side of the leaves. If you want to make sure you catch them all, place a sheet of newspaper underneath the plants first. That way, if caterpillars drop down, you can easily find them again.

3. Vampire spray

An easy-to-make garlic spray can be used to ward off the butterflies from chosen plants. Add two bulbs of garlic to half a cup (approximately 125ml) of boiling water and let it steep in a bowl or cup overnight. The longer you leave it to steep, the more potently it works. If you wish to have an even more aggressive mixture, you can add chili peppers or chili flakes for some additional heat. Strain the mixture through a sieve into a plant mister or spray bottle, and spray your brassicas every ten days (don’t forget the underside of the leaves) with the home-made garlic spray, repeating if there’s rainfall.

4. Nasturtium buffets

The nasturtium is another favourite plant for the cabbage white butterfly. If you restrict access to your brassicas (by netting, for example), the butterflies will certainly hone in on these pretty, edible flowers. By offering them a veritable nasturtium buffet, you might help them procreate without having to sacrifice your veg. Note, they will go for the brassicas first whenever possible.

Nasturtium seeds

@fleurrustique

5. Crafty butterflies

You can battle cabbage whites with ... more cabbage whites. Once the female has copulated, the only thing she seeks is a suitable, quiet spot to lay her eggs. Once she spots male butterflies, she tends to avoid that location, since she doesn’t want to be harassed by him. Placing visible, male cabbage white effigies on brassica patches helps to ward off egg-laying females from those locations.

You can find our own crafty guide to making your own brassica white males here as a PDF for printout below. Laminating them helps them to survive a sudden shower.

In the end, it’s a matter of balance. If your brassicas aren’t destined for market, a few holes aren’t going to bother anyone. For maximum effect, you could use all our tips, improving your chances of keeping the caterpillars away from your vegetables while still offering the butterflies a viable alternative to procreate.

After all, who doesn’t like butterflies in their garden?