How to use yellow sticky traps against fungus gnats and other pests


I study landscape ecology and through my studies have discovered a love for plants. Plants are not only beautiful, but also have countless fascinating survival strategies. To bring a bit of nature into my home as well, I nurture my houseplants and herbs on every possible windowsill.

Favourite fruit: rhubarb and all kinds of berries
Favourite vegetables: onions and garlic

Most gardeners are familiar with sticky insect traps. Find out how yellow sticky traps work, how to use them properly and what to bear in mind when doing so.

Insects stuck to yellow sticky trap
Yellow sticky traps help to detect and monitor pest infestations [Photo: MarcOliver_Artworks/]

Have you ever seen yellow sticky traps in or around plants and wondered what they are for?

Yellow sticky traps are an effective means of detecting pest infestations at an early stage and enable you to act fast against the insects in question. You can use them to monitor a pest infestation both indoors and in greenhouses. While you can also use yellow sticky traps outdoors, in orchards for example, there is a risk that the traps will catch beneficial insects alongside the destructive pests.

But how do you use yellow sticky traps correctly, and which pests are they effective against? Read on to find out how yellow sticky traps work and how to use them properly.

How do yellow sticky traps work?

Sticky traps are insect traps made of plastic or cardboard and are covered with a layer of glue. They take advantage of certain insects’ natural instincts in order to lure them towards the trap. The insects then get stuck to the layer of glue on the trap and die.

Yellow sticky traps do not require pheromones or insecticides to attract and catch the insects. They are drawn to the trap solely because of the colour. That said, some sticky traps do contain pheromones to make them more effective and to catch specific insects. The pheromones can help to attract large numbers of insects that are biologically drawn to the respective sex hormones.

Many insects caught on yellow sticky trap
The colour yellow attracts many insects and is the reason they are lured to yellow sticky traps [Photo: Pixelbender36/]

If you have ever worn a yellow t-shirt outdoors in summer, you will know that the colour yellow tends to attract a variety of insects. But what is it about the colour yellow that attracts insects? Again, it all comes down to the insects’ biological instincts. Insects need pollen and nectar to survive and yellow flowers often provide plenty of both. This is why some insects are attracted to the colour yellow, and it is precisely this attraction that yellow sticky insect traps make use of.

Did you know? There are different types of sticky traps, including blue sticky traps, which attract different types of insects than the yellow ones.

Small yellow sticky trap in houseplant
Indoors, yellow sticky traps are useful all year round [Photo: Johannes Ziegler Photo/]

How to use yellow sticky traps correctly

Yellow sticky traps can either be hung near the plants or stuck directly into the soil using a trap holder. Our Plantura Yellow Sticky Traps come with ten reusable metal trap holders as well as wire for attaching them to plants, so you can use them either way. Depending on the severity of the infestation you are dealing with, you can either use the yellow sticky fly traps whole or split them into two smaller traps by cutting them in half down the middle. Our yellow sticky traps can be used indoors all year round or in greenhouses or outdoors from the end of March onwards, once pests start becoming active. Bear in mind, however, that beneficial insects can also stick to the traps if you use them outdoors.

Yellow Sticky Traps 20-pack
Yellow Sticky Traps 20-pack
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  • For detecting infestations early on and monitoring pest populations
  • 20 double-sided yellow sticky traps (or 40 smaller traps) to hang from plants or stick straight into soil
  • Odourless & insecticide-free

Yellow sticky traps for pest control

Yellow sticky fly traps, such as our Plantura Yellow Sticky Traps, are great for monitoring infestations and, in some cases, also help to minimise pest numbers. Here are some of the kinds of insects you can catch using yellow sticky traps:

  • Winged aphids (Aphidoidea)
  • Whiteflies or greenhouse white flies (Trialeurodes vaporariorum)
  • Fungus gnats (Sciaridae)
  • Thrips (Thysanoptera), especially grape thrips
  • Fruit flies (Drosophila)
  • Leaf-miner flies (Agromyzidae)
  • Green leafhoppers (Empoasca vitis)
Close-up of whiteflies on leaf
Yellow sticky traps have a strong effect on whiteflies [Photo: D. Kucharski K. Kucharska/]

Yellow sticky fly traps can help detect an infestation at a very early stage. This allows you to start tackling an infestation as soon as you notice it and get it under control before things get out of hand. Sticky traps are also useful for indicating how successful control measures have been. Of course, they are not only useful in greenhouses and outdoors, but can also be used indoors to help with pests that like to infest houseplants. You can, for instance, use yellow sticky traps for detecting fungus gnats, which can be a nuisance in our homes. See our article on fungus gnat control for more information on combatting these pesky little flies.

Remember: Yellow sticky traps are not meant as a pest control method in and of themselves. This is because there will always be a few insects that escape the traps and will therefore be able to continue to reproduce. Besides, the real damage is often caused by the insect larvae that live in the soil which the traps simply do not catch.

Close-up of insects stuck on yellow sticky trap
Yellow sticky traps are ideal for monitoring the development of pest populations [Photo: Catherine Eckert/]

Using yellow sticky insect traps properly:

  • Generally speaking, one yellow sticky trap per plant stand or one per square metre is sufficient to monitor a pest infestation.
  • Try to evenly space out the yellow sticky traps around the infested area.
  • The traps usually remain effective for a very long time, so you will rarely need to replace them. Our Plantura Yellow Sticky Traps, for example, last for at least six months.

Note: If you are dealing with a severe infestation, yellow sticky traps will fill up with insects in no time. When this happens, we advise placing more traps in and amongst your crops or houseplants and replacing them sooner (and more often).

Do yellow sticky traps pose a danger to beneficial insects?

Bees, ladybirds and other beneficial insects rarely stray into our house or greenhouses, so the risk of accidentally catching them is relatively low. That said, you should think twice before using traps outdoors, as there is no way of ensuring that no beneficial insects or small birds will fly into them.

Tip: Yellow sticky traps are one of the few methods of preventing spotted wing drosophila (Drosophila suzukii) from laying eggs in your cherries. When using yellow sticky traps in cherry trees, it is important to only leave them there between May and June and to remove them immediately afterwards. This will prevent too many other insects from accidentally getting stuck to the traps. See our article on the spotted wing drosophila for more information.

Beneficial insect stuck on yellow sticky trap
When using yellow sticky traps outdoors, the risk of accidentally catching beneficial insects is very high [Photo: andras_csontos/]

Are pests raiding your garden and ruining your crops and plants? Before you reach for harmful chemical insecticides, why not consider making your garden more welcoming to beneficial garden animals? They help to control pest populations in a natural and environmentally-friendly way.

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