Big Fat Worm on Basil – Backyard Food Growing


So I caved and actually bought a couple of basil plants from the store (Walmart), I just wanted more of it and the season was passing quickly.  There wasn’t enough time to sprout more seeds. I’m sure you already know that there’s never too much basil! This is another lesson in why it’s always better to buy plants from reputable nurseries.

The plants are doing beautifully and were growing nicely. I watched them for a couple of weeks while they grew and made more leaves. 

I hadn’t pinched any yet and was tenderly nurturing these new additions, but then I started to notice some of the branches looked as though they had been harvested or pinched already. After some inspection of the plants, I discovered these absolutely huge green, fat worms on there happily devouring my basil!

I researched them to be Cabbage Worms (Pieris rapae). They will consume basil as well as many other things in the Cabbage family, hence their name.

Cabbage Worm Diet

They will happily eat cabbage, broccoli, brussel sprouts, kale, cauliflower and basil voraciously. If given the opportunity they will likely eat other plants too, keep your eyes peeled for them when your plants are young and fresh in the spring and early summer.

A sharp eye is needed as they are hard to see because their colour is often perfectly matched to the plant they are on.

This pest can be a prolific problem out in the garden if left unchecked. This particular worm and a few of his friends hitched a ride into my living room on the basil I bought at the store. 

The plants all had to be cut down and only some of it could be harvested. If you have these worms on your basil, then choose one of the recommended remedies below. If you have a lot of hitch hikers into your home then just destroy the whole plant.


There are a few remedies that you can choose from depending on how squeamish you are.

You can choose BTK (Bacillus thuringiensis kurstakis) concentrate and make a diluted spray out of it or you can choose hand picking or using row cover material if you’re planting outside.

BTK spray is a natural pesticide comprised of a certain BT bacteria named “kurstakis” that attacks worms and caterpillars only.

Bacteria in general is not necessarily bad and is present in numerous forms and places including in our food, in the soil we grow our food and on our bodies as well. This specialized bacteria is known to attack and weaken the caterpillars, larvae and other worm like creatures such as the Cabbage Looper.

The caterpillar must eat the BTK in order for it to work. BTK doesn’t work on adult butterflies or pupae, it is only effective on caterpillars and most effective on young caterpillars.


BTK has been approved and available for sale in Canada for 30 years. It is always recommended as a plan of attack for this type of pest because it’s not harmful to any beneficial insect, birds, humans or domestic pets.

If you notice fast moving white coloured butterflies in the spring then you’ll know that you are a facing an upcoming fight with Cabbage worms in the upcoming season.

Hand picking

Hand picking is just as fun as it sounds. Go around your garden and pick them off one by one. It’s a little easier if you put on a pair of gloves that allow you to have good dexterity.

Then use a small container with a lid and take a trip around the garden looking for the nasty pests. Pick them off as you find them and put them in the container, then put the container in the garbage or just wait for them to suffocate and die, then dispose of them later.

Row Cover

This pest control method is usually used in larger scale farming and gardening, but also can prove effective in small areas as well. 

Apply the row cover early in spring as soon as you plant. One drawback with this product is that the packages are usually quite large and will be much more than you need if you are doing small space gardening.

Keep the product dry and it will be good to use for many years. If you have a gardening neighbour nearby then share the package with them.


A second drawback to row cover is that it holds out a lot of rain and it cuts sunlight penetration to approximately 85%. However, row cover is great for protecting your plants from pests as well as bad weather such as hail. 


You read that right. Tulle, the same stuff that is used in weddings and other events. This product works great for a job that it was never intended. Tulle works because it has tiny holes large enough for rain and 100% of sunlight to get through but not at all large enough for garden pests to get through. 

The Adult

This is what the Cabbage worm looks like after it pupates and changes into a flying insect, known as a Cabbage Worm Butterfly.

It can be confused with a regular pasty white moth but these are indeed a more destructive creature. They look nothing like a lovely butterfly so should be easy to spot around your garden. Using these methods should help you get rid of this pest for good.