Almost all information about plants has been included with the plants in our free app. So, you don't need to remember it. View the MM app

Pests in the garden: from aphids to caterpillars

Aphids, ants, slugs, caterpillars, grubs, and leaf-miner flies: just a few of the pests you would rather not see around your plants.
But before you reach for a spray bottle, first check if you may be part of the cause. And what you can do about it:
Bringing in their natural enemies and using - eco-friendly - pesticides should be a last resort. Most of the time, you don't actually need them in a Planty Garden. 
Got it? Good 🙂  So, let's continue with Kristin's tips. She knows a lot about organic gardening. 
Kristin op inspectietocht
Kristin inspecting her plants
Here Kristin lays out what you can do to fight pests when you have a serious infestation on your hands:

Aphids and ants

Aphids can come out en masse on warm spring days. They absorb sugard from your plants by sucking juices from the leaves. Since they're literally sucking the energy from them, the plants won't grow as well. 
Aphids convert the sugars they don't need into a sweet liquid - honeydew - and deposit this on the leaf. Black sooty mold then develops on these leaves, which also inhibits the plant's growth. 
On top of that, ants love honeydew. So they may even herd the aphids and tend to them like livestock. They encourage them to release the honeydew and transfer it to other plants. 
Mieren houden luizen als vee
Ants herd aphids so they produce more honeydew
Aphids are also useful

Some predatory insects eat aphids in the spring as their first food source. Later, they move on to mites. So, aphids are also an important link in the food chain. 

How do you limit the damage?

 1: Get rid of the aphids 

Pick them off or cut off the damaged parts. Spray the affected plant repeatedly with a powerful jet of water. But be careful not to damage the plant. After a few days, look for dead or uneaten aphids. This is a sign that natural enemies are already at work. Then wait quietly. 
2: Plant catch plants 
Indian cress, marigold, sorrel, feverfew, and elderflower attract black aphids. These are their favorites, so your other plants won't be as interesting to them. 

3: Deploy natural enemies 
Make your garden friendly to birds and predatory insects. You can even order ladybug larvae or of the native lacewing Chrysopa carnea. The larvae eat a lot of aphids. 
Goudsbloemen trekken zweefvliegen aan
Marigolds attract hoverflies and aphids
Same goes for hoverfly larvae. And hoverflies love marigolds: all the more reason to put them in or near your garden boxes. They also like dill, cilantro, and fennel flowers. 

Natural repellents

Insecticides should be a last resort. Only bring out the -eco-friendly - sprays when the other methods don't work well enough. 
You can spray the aphids themselves and the underside of the leaves. Never spray in full sun: it can burn your leaves. 
Garlic spray: Garlic spray works well on aphids. Just skip spraying your tomato and cucumber plants: they don't like it. 
Soapy water: Take a liter of lukewarm water and dissolve a tablespoon of old-fashioned green soap in it. After cooling, add a dash of alcohol if necessary. 
Neem oil: This is a natural oil made from the seeds of the Indian neem tree. Age-old, tried-and-true remedy. Acts on the molting system of sucking insects, which kills them. Recipe: 1% neem oil, 2% soap and 97% water at 40°C. Shake well and allow to cool slightly. 
Stinging nettles extract: Let a few handfuls of dried or fresh stinging nettles soak 12-24 hours in cold water. Strain and spray undiluted. 
Rhubarb extract: Pour a bucketful of fresh rhubarb leaves into boiling water and leave for 12 hours to cool well. 
Diatomaceous earth (celite) spray: Mix one tablespoon of diatomaceous earth with one liter of water and spray the affected parts of your plants. You have to spray the aphids themselves, otherwise it won't take effect. The celite sticks to the aphids' outer shell (carapace). The more the aphid moves, the more the celite abrades. This causes the aphid's shell to break down, dehydrate, and eventually it dies. 

Diatomaceous earth, or celite

Diatomaceous earth can be used to fight off many more harmful insects.  
It is a powdery soil that consists of fossilized remains of small organisms: diatoms. The edges of diatoms are razor sharp and they abrade the protective layer of insects. Because celite also absorbs moisture, insects that come into contact with it dry out. 
Be careful not to inhale celite or get it in your eyes: it's dehytrating effect isn't good for you either. And don't forget to wash your hands after using it. 


Caterpillars can strip a plant bare in no time. 
Early on, you'll see green or black droppings and small holes in the leaves. You should check for caterpillars and remove them right away. Some have perfect camouflage, so it might be tough to see them:
Rupsen van het koolwitje hebben een goede schutkleur
Rupsen van het koolwitje hebben een goede schutkleur
But: if you want butterflies, you'll also have to accept some caterpillars. They're also an important food for birds and for parasitic wasps - which eat aphids too. 
Caterpillars always eat from a specific kind of plant. Cabbage whites lay their eggs on plants in the kale family. Their caterpillars will bother you the most.
Cabbage white butterfly on a radish leaf


Ants eat plant roots, which dries out the rest of the plant. They also corral aphids and spread them to other plants. They build nests under tiles, which can cause them to sink.

On the other hand, they aerate and mix the soil, eat organic waste, and are themselves food for many other animals. 

So, only if they're making trouble by building huge nests in your garden box, scatter some celite on the spot. 

Leaf miners

Leaf miners are larvae of flies or butterflies that eat the chlorophyll inside the leaf. Because they are inside the leaf itself you hardly see them, but you can recognize them by their bite marks: brown lines or large spots in the leaf.
Aangetast snijbietblad
An affected chard leaf
  • Remove the infested leaves, especially from leafy greens.
  • Use the MM-Muts crop cover or place insect over your garden box in time.
  • Spray with diatomaceous earth spray if necessary.
On snow peas and bean plants, they do less harm: they only attack the leaves, not the pods. 

Leaf miner damage to bean leaves


Scarab grubs are larvae of leafhopper beetles, like the mayfly and June beetle. They appear in summer and fall. They feed on the roots of various plants and grasses. The plant will then suddenly wilt. 
Wire worms do the same thing. They're the larvae of the click beetle. 
Verwelkt kropje sla en de boosdoener
Wilted lettuce on the left, culprit on the right
Moth larvae: These are chubbier and eat the bottom-most part of the stem. With the same result. 
If you see a wilted plant, look for the larvae in the soil mix and dig them out. If you can't find them, put a piece of potato in the vegetable patch. When you dig it up again a few days later, there's a big chance you'll find them.
If the damage is serious, you can use nematodes. These are small, parasitic worms that eat slugs and other pests. You can buy them online. 

Leather jackets

Leather jackets aren't as cool as they sound. They're crane fly larvae. They appear in the garden from fall to spring. 
Leather jackets are dark gray, 2-4 cm long, and are leathery to the touch. They don't have a distinct head, and won't roll up when touched. They sleep underground during the day and come up at night to eat stems and leaves. 
Wet the soil mix at night and lay black plastic wrap on top. In the morning you can then remove the leather jackets from the foil. Major infestation? Use nematodes.


Woodlice have a lot of names: potato bugs, pill bugs, rollie pollies. They're waste eaters that live in the garden year round. They like moist dark corners. Woodlice are good for cleaning up organic waste, but also eat strawberries and roots of young seedlings. 
Use a hollowed-out potato to catch and remove them.

Bean fly

The bean fly appears in April and May and lays its eggs on young bean seedlings. The seedling leaves develop brown bite marks, the tip of the plant is consumed, preventing the plant from growing. 
You can pre-sow the beans indoors and plant them in the garden box when it is warm enough outside. The young plants should have about 3 leaves. 
If you sow beans directly in the ground, then cover it with the MM-Muts or another crop cover made of fleece or netting. 

Cabbage fly

The cabbage fly lays its eggs mainly between mid-May and mid-June. It does this between the roots and the stem of cabbage plants, radishes, and other cruciferous plants. 
The larvae are white and up to 1 cm long. They can move a short distance: about 3 cm. They eat the roots, so that eventually the plants no longer transport water to the stem. The plant then becomes weak and dies. 
  • Place a crop cover like the MM-Muts over your cabbage plants to prevent flies from laying eggs on the roots. 
  • Place around all your kale or cabbage plants. You can make your own from cardboard or old bicycle tubes. Cut a circle 10 cm in diameter. Place it around the base of the plant's stalk.
  • Create confusion by putting many different strongly scented plants in and around your garden box.

Carrot fly

Carrot flies lay eggs at the base of plants of carrots, parsley, dill, cilantro, and caraway plants. The larvae eat passageways into the roots and stems. 
  • Always harvest your square patch of carrots completely. The fly can easily overwinter in left-behind carrots.
  • Use the MM-Muts crop cover or insect netting. 
  • Ward them off by planting strong-smelling plants like garlic, onion, shallot, or leek nearby.
  • When thinning, use scissors to minimize plant damage and release scents. 

(Leaf) beetles

Leaf beetles are beetles with a beautiful shiny shell. Each beetle has a preference for a particular plant group. For example, you'll only find the Chrysomelinae beetle on mint: 
Goudhaantjes op de munt
Chrysomelinae leaf beetles love mint best
Larvae and adult beetles like the same plants. They eat the top of the leaf or nibble holes in it. 
The best way to prevent an infestation is to look for the beetles and larvae in spring and summer and remove them. 

Potato flea beetles

Do you see small holes in the leaves of your radish, arugula, beet, or cabbage plants? Then you're probably dealing with potato fleas. 
These are small beetles - sometimes only 1.5 mm in size - that you can barely see, but you can see them jumping away when you touch the leaf. Just like fleas, hence the name. 
They are especially common in spring and summer, in warm, dry weather. The beetles chew small round holes the leaves, but also eat pathways through the radishes and beets. Small seedlings can die as a result. 
The solution? Keep your soil mix moist, they don't like that. If you have a serious infestation, you can coat one side of a plank with glue (wallpaper paste) and move it around just above the plants. The idea is that when they jump, they'll stick to it 😉  These beetles are not easy to control. 

Earwigs - often a blessing, not a curse

Earwigs are often seen as harmful, but often the opposite is true. They clear away dead leaves and eat aphids and the eggs of insects, including those of the cabbage whites. 
Do you want to lure them away from your vegetable garden box? Then fill a jar with straw, hang it upside down on top of a stick nearby, and after a few days, empty it in another spot. 
Potje met stro om oorwurmen te vangen - foto Silvia

Long story short

So, now you have solutions for the most common vegetable garden pests. Thanks Kiristin 🙂  But like I said, in a Planty Garden you usually don't have to deal with them that much. 
Gats: een slak op een MM-mini
Oh boy, a slug on the MM-Mini
In case you miss the snails and slugs in this overview, don't worry. I have a whole chapter dedicated to them:
You got this!
Source: Pest book. S. Peters, L. Stekelenburg, Velt. Publisher Trichis, 2018

Get tips & tricks in your inbox

When you sign up, I’ll send you the top 3 things beginners get wrong. And how you can get it right.

We care about the protection of your data. Read our Privacy Policy

Our perks