These 5 Pests & Diseases Can Be A Real Pain For Broccoli Growers – Here’s What To Do
Elizabeth is a Permaculture Garden Designer, Sustainability Consultant and Professional Writer, working as an advocate for positive change. She graduated from the University of St. Andrews with an MA in English and Philosophy and obtained a Diploma in Applied Permaculture Design from the Permaculture Association.
Reviewed By DAN ORI
Dan has over 27 years’ under his belt caring for plants and gardens. Working as a Horticultural Instructor and Consultant, he draws on a diverse range of experience that includes working as a Head Gardener, Tree Surgeon, Garden Centre Trouble Shooter, and writer of academic papers. Dan has a Level 3 Diploma in Horticulture and is currently a candidate for the RHS’s most prestigious award – The Master of Horticulture.
Broccoli is a relatively easy crop to grow in your garden and you should find it relatively straightforward to care for if you place it in the right location.
However, as with most crops, broccoli can experience problems with a range of pests and diseases.
Some of the most common pests and diseases encountered when growing broccoli include:
- Birds
- Cabbage white caterpillars
- Cabbage root fly
- Club Root
- Mildews and moulds
While there are also other problems that might arise, these are the most common broccoli issues for UK gardeners.
1) Birds
Birds are, of course, wonderful in a garden, bringing a range of benefits to the local ecosystem.
Unfortunately for gardeners, they can also sometimes become a pest problem too.
Broccoli is one plant (along with other brassicas) that birds like pigeons often love to eat.
If you do not take steps to cover your plants, they can easily damage your crops and can even entirely consume all of the plants you are lovingly trying to grow.
If birds damage and eat brassicas in your area, it is best to cover your crop as soon as they are planted out, placing cloches, row covers or netting over beds where they are grown to keep them safe.
Bird scaring strategies can sometimes work briefly, but won’t typically work for long as I find that birds tend to get used to them, so physical barriers are usually the best option.
“For my brassicas, I use a fine mesh fabric over a frame with the bottom of the fabric weighted down to create a sealed-off enclosure,” shares Master Horticulturist Dan Ori.
“I find good weed management before sowing and the willingness to live with a few weeds coupled with drip hose watering means that I don’t need to unseal my brassica enclosure very often, which reduces the opportunities for pests to get in.”
2) Caterpillars
Caterpillars, particularly those of the cabbage white butterfly, are another common problem for Calabrese and other brassicas.1Broccoli | Diseases and Pests. (n.d.). Plant Village. Retrieved March 13, 2023, from https://plantvillage.psu.edu/topics/broccoli/infos
Physical barriers are also the best way to prevent cabbage white butterflies and moths from laying their eggs on your broccoli plants.
Cabbage white caterpillars and other caterpillars are another major broccoli pest and you can lose the entirety of your crop to a serious infestation.
In the case of a minor infestation, you may be able to pick off caterpillars by hand, but fine netting is the best option when it becomes a more serious problem.
Placing decoy butterflies (made from white plastic, for example) is said by some to help – and companion planting can also aid in keeping down pest species to a degree.
But a physical barrier is really the only sure-fire way to keep your brassicas safe.
3) Cabbage Root Fly
Fine insect netting or some other physical barrier protection will also protect your broccoli from another major pest of this crop – the cabbage root fly.
The flies lay their eggs in the soil below the plants and these turn into white larvae which eat the roots and can kill your plants.
Covering the area, especially in the early spring, can help reduce the chances of this problem taking hold.
4) Club Root
Broccoli can also be prone to fungal infection and one of the main fungal infections encountered when growing this crop is club root.
Club root is a fungal infection caused by Plasmodiophora brassicae.2McGrann, G. (2016). Plasmodiophora brassicae (club root). CABI Compendium, CABI Compendium. https://doi.org/10.1079/cabicompendium.41865
It causes swollen and distorted roots on broccoli and a range of other related plants between midsummer and late autumn.
This can lead to stunted growth, wilting foliage in hot weather, and purplish discolouration of the leaves.
Growth and yield are typically affected, and plants with a severe case of this issue can die.
I would argue that prevention is always better than cure when it comes to club root.
Make sure broccoli plants come from a club-root-free source – and don’t grow brassicas in any soil where this has previously been a problem.
Club root can be more common where soil is too acidic, so liming can help to reduce the chances of this problem in acidic soils.
Unfortunately, this is a problem that can remain in the soil for up to 20 years.
5) Mildew & Mould
Club root is not the only fungal problem that you might encounter when growing broccoli.
Mildew and mould present on the leaves can also become an issue.
Mildew and moulds are more likely to take hold when the environmental conditions are less than ideal, so make sure that you grow brassicas like broccoli in suitable soil and a suitable spot and care for them correctly.
If such a problem arises, take steps to remove affected leaves or plant portions as soon as possible to prevent their spread.
Remember, these are just some of the problems for which you should prepare when growing broccoli.
Simple steps such as positioning plants correctly, good hygiene, physical barriers and crop rotation can help keep any problems from spreading out of control.
