What Is Making Holes in My Brussels Sprout Leaves? Find Out

If you’re thinking, “What is making holes in my Brussels sprout leaves,” then you’re at the right spot. The most likely cause is hungry pests like caterpillars, beetles, or slugs that love to chew through the leaves.

But remember – each pest creates different holes and it’s crucial to know about them.

Stick around, and I’ll walk you through how to identify each pest and stop them from damaging brussels sprout leaves!

Key Points from the Blog

• Cabbage worms cause large, irregular holes in Brussels sprout leaves.
• Flea beetles leave tiny pinholes across the leaves.
• Slugs and snails leave large holes, often with slimy trails.
• Cabbage loopers create ragged gaps by chewing the leaves.
• Cutworms chew irregular holes, often near the base of plants.
• Leaf miners leave squiggly lines or tiny holes by tunneling inside leaves.
• Protect your plants with natural methods like handpicking, row covers, and beneficial insects.

What is making holes in my brussels sprout leaves? The Details

Small to large holes in your Brussels sprout leaves are most likely caused by pests like caterpillars, slugs, or flea beetles. These insects chew on the leaves, leaving irregular or small, pinhole-sized holes.

Cabbage Worms: The Green Leaf Munchers

Cabbage worms are usually the culprits in most cases. They are the larvae of moths or butterflies, and look really beautiful. Sadly, they also love feeding on the leaves.

How to Identify Cabbage Worm Damage

• Large, irregular holes in the leaves
• Green caterpillars blending with the leaves
• Small black droppings on the leaves

How to Stop Cabbage Worms

• Handpick worms: Inspect your plants and remove the worms by hand.
• Natural spray: Use a mixture of water and dish soap to spray the leaves.
• Introduce beneficial insects: Release ladybugs or parasitic wasps, which feed on cabbage worm eggs.
• Cover plants: Use netting or row covers to keep butterflies from laying eggs on your plants.

Massimo E. Maffei says that if insect infestations aren’t controlled early, they can cause irreversible damage to the plants.

Flea Beetles: Tiny but Mighty

Flea beetles are small insects that leave tiny, pinhole-sized damage on Brussels sprout leaves.

How to Spot Flea Beetle Damage

• Tiny, round holes across the entire leaf
• Leaves look like they’ve been peppered with small bites
• Flea beetles jump off the plant when disturbed

How to Protect Your Plants from Flea Beetles

• Floating row covers: Use these to prevent flea beetles from reaching your plants.
• Plant trap crops: Flea beetles love radishes more than Brussels sprouts, so plant radishes nearby to attract them.
• Neem oil spray: This natural oil can help deter flea beetles.

Slugs and Snails: Slow But Destructive

Slugs and snails leave large, ragged holes in Brussels sprout leaves, especially in damp or wet conditions. They often leave a telltale slimy trail behind.

How to Tell if Slugs and Snails are the Problem

• Irregular, large holes in the leaves, often appearing overnight
• Slimy trails on the leaves and soil

3 Ways to Get Rid of Slugs and Snails

• Handpick at night or early morning: Go out when they’re active and pick them off the plants.
• Set traps: Use shallow dishes filled with beer to trap and drown slugs. Moreover, place copper tape around your plants, as slugs won’t cross copper.
• Reduce moisture: Water plants in the morning to keep the garden dry at night, making it less inviting for slugs and snails.

Cabbage Loopers: The Leaf Chompers

Cabbage loopers are the green caterpillars that you see in your garden. They move in a looping motion and chew large, ragged holes in the leaves of Brussels sprouts.

How to Spot Cabbage Looper Damage

• Large, ragged holes in the leaves
• Green caterpillars often found on the underside of leaves
• Little black droppings, similar to cabbage worms

How to Control Cabbage Loopers

• Handpick caterpillars: Regularly check and remove cabbage loopers by hand.
• Use Bacillus thuringiensis (Bt): This natural insecticide specifically targets caterpillars.
• Encourage parasitic wasps: These wasps lay eggs in caterpillars, killing them.

Aphids: The Sneaky Suckers

Aphids don’t create holes directly but weaken the plant by sucking out its sap, which makes the plant more vulnerable to other pests that do cause holes.

How to Know if Aphids are the Problem

• Yellowing leaves or curled edges
• Sticky honeydew substance on the leaves
• Clusters of tiny green, black, or white bugs on the stems or underside of leaves

How to Deal with Aphids

• Spray with water: Knock aphids off the plant with a strong water spray.
• Natural predators: Introduce ladybugs or lacewings to feed on aphids.
• Soapy water spray: Mix a mild dish soap with water and spray the leaves to kill aphids.

Cutworms: The Nighttime Chewers

Cutworms are larvae that are active at night and chew through the leaves and stems of plants like Brussels sprouts. These pests can leave large, irregular holes in the leaves, and sometimes they’ll even cut through the stems, causing the plant to die.

How to Identify Cutworm Damage

• Large, irregular holes in the leaves, especially at the base of the plant
• Plants that are cut at the stem, causing them to wilt or die
• Damage often appears overnight

How to Control Cutworms

• Use collars: Place cardboard or plastic collars around the base of the plants to prevent cutworms from reaching the stems.
• Handpick at night: Go out in the evening or early morning to check for cutworms and remove them by hand.
• Spread diatomaceous earth: This natural powder can be sprinkled around the base of your plants, which cuts and dehydrates the cutworms as they crawl over it.

Leaf Miners: The Tiny Tunnelers

Leaf miners are harmful because they lay their eggs inside the leaves of Brussels sprouts. When the larvae hatch, they tunnel between the layers of the leaf. This activity creates small holes or visible trails that look like lines or squiggles.

How to Spot Leaf Miner Damage

• Visible winding tunnels or squiggly lines on the leaves
• Small holes where the larvae exit the leaves
• Damaged leaves that turn yellow or brown

How to Stop Leaf Miners

• Remove affected leaves: Cut off and destroy any leaves that show signs of leaf miner damage.
• Use row covers: These will prevent adult leaf miners from laying eggs on your plants.
• Introduce beneficial insects: You can purchase predatory insects and release them in your garden to control leaf miners.

Harlequin Bugs: The Sap Suckers

Harlequin bugs are brightly colored pests and many people find them adorable. However, they suck the sap from Brussels sprout leaves, leaving behind small holes and deformations.

These bugs can be particularly harmful to younger plants, as they weaken them and make them more susceptible to other pests.

How to Identify Harlequin Bug Damage

• Small, irregular holes and deformations in the leaves
• Yellow or brown spots on the leaves where the bugs have sucked the sap
• Brightly colored black and red bugs on the plants

How to Manage Harlequin Bugs

• Handpick bugs: Pick off the bugs by hand and drop them into soapy water to kill them.
• Use row covers: Keep bugs off your plants by covering them with floating row covers.
• Trap crops: Plant mustard or radishes nearby to attract the harlequin bugs away from your Brussels sprouts.

Grasshoppers: The Big Chewers

Grasshoppers can be another reason for large, uneven holes in your Brussels sprout leaves. They eat a variety of plants and can cause significant damage if left unchecked.

How to Spot Grasshopper Damage

• Large, uneven holes in the leaves
• Grasshoppers visible on or near the plants
• Damage tends to appear during the day

How to Control Grasshoppers

• Apply natural predators: Birds, frogs, and beneficial insects like praying mantises can help keep grasshopper populations in check.
• Spray with garlic or hot pepper: A spray made from garlic or hot pepper can deter grasshoppers from eating the leaves.

While you’re protecting your Brussels sprouts from pests, make sure your tomatoes are safe too. Here’s what to do if caterpillars have damaged your tomato plants.

Less Common Reasons Behind Holes in Brussel Sprouts Leaves

In some cases, environmental and nutritional factors can cause holes in the brussel sprouts leaves. Let’s have a look:

Weather Damage: Nature’s Wrath

Sometimes, the holes in your Brussels sprout leaves aren’t caused by insects at all but by extreme weather conditions. The two common ones are:

• Strong wind
• Hail.

These natural events can tear or puncture the leaves, leaving them with holes.

How to Recognize Weather Damage

• Torn or shredded leaves, usually after a storm
• Holes that appear suddenly and are uniform in size
• No signs of insects or pests on the plant

How to Protect Your Plants from Weather Damage

• Use garden cloches or row covers: Protect your plants during storms or high winds by covering them.
• Stake or support plants: Provide extra support to your Brussels sprouts to keep them from being damaged by the wind.
• Prune damaged leaves: Remove any severely damaged leaves to encourage new growth.

Nutrient Deficiency: Weak Leaves

Although rare, nutrient deficiencies in your Brussels sprouts can weaken the leaves. Weak leaves are more prone to tearing or developing holes. If the plant is not getting the proper nutrients, the leaves can become fragile.

According to Przemysław Barłóg, nitrogen helps plants produce the carbohydrates they need to survive and grow. Similarly, according to Plants (Basel), Phosphorus (P) helps plants deal with abiotic stresses such as drought and heat stress.

How to Spot Nutrient Deficiency Damage

• Weak or thin leaves that tear easily
• Yellowing or pale leaves, indicating poor nutrition
• No signs of pests, but the plant looks unhealthy overall

How to Fix Nutrient Deficiencies

• Test the soil: First, use a standard soil test kit to check for deficiencies in nutrients like nitrogen, potassium, and magnesium.
• Add organic fertilizers: Apply compost or well-balanced organic fertilizers to improve the soil.
• Mulch around the plants: Mulching helps retain moisture and slowly releases nutrients to the soil over time.

While you’re figuring out what’s eating your Brussels sprout leaves, check out these tips on fixing red leaves on blueberry plants for more plant care advice.

Conclusion

All in all, insects like cabbage worms, flea beetles, etc., make the holes in brussels sprout leaves. To protect the plant, remember to:

• Check your plants regularly for pests.
• Use row covers to keep bugs out.
• Handpick larger pests like caterpillars and slugs.
• Try natural sprays like neem oil or soapy water.
• Release beneficial insects like ladybugs to help control harmful insects.

That’s all.