Everyone knows the yellow boards that catch insects. We show what you should pay attention to when using and how you can make yellow plates yourself.
Yellow panels help identify and monitor insect infestation [Photo: MarcOliver_Artworks / Shutterstock.com]
Many of you have probably seen these sticky yellow signs before and wondered what they are all about. Yellow boards are an effective means of recognizing a pest infestation at an early stage and thus being able to act quickly. The yellow glue traps can be used both in greenhouses and indoors to monitor pest infestation. They are even used outdoors, for example in orchards. There, however, there is a greater risk that, in addition to the pests, some useful animals will also fall into the trap. How exactly should you use yellow panels and which pests do they work against? We will address these questions below. But first we clarify how yellow tables actually work.
How do yellow boards work?
If you've ever been outdoors in the summer wearing a yellow shirt, you know that this color is extremely attractive to insects. The yellow boards take advantage of this stimulus and attract the little animals. The insects then stick to the glue layer on the boards and are thus caught. Such exploitation of the insect's own stimuli is part of biotechnological plant protection.
Yellow is attractive to insects. In this way they are lured away from the plant to the boards [Photo: Pixelbender36 / Shutterstock.com]
But how do the yellow tablets work in particular and why are the insects drawn to them like magic? Ultimately, there is only an instinct of these insects behind this, because they need pollen and nectar for their nutrition, which they often find in yellow flowers. Therefore, they are attracted to the color yellow – this is exactly the mechanism used by the yellow tablets.
The yellow boards available are either made of plastic or cardboard and are coated with a layer of glue. However, neither pheromones nor insecticides are needed to attract and catch the insects. The insects are only attracted to the yellow color and stick to the glued layer. However, some yellow bars also add pheromones to increase effectiveness and specificity. Because this particularly attracts large numbers of those insects that fly on the respective sex hormones.
Use yellow tables correctly
You can either hang yellow boards near the plants or stick them in the ground on a stick. If you decide, for example, to buy our Plantura yellow boards, you have both options, because they are supplied with ten reusable metal plugs and with binding wire for hanging. Depending on the infestation situation, the yellow panels can be used as a whole or simply cut in half at a dividing line. Our yellow boards can be used indoors all year round and they can also be distributed in the greenhouse or outdoors from the end of March, because the first pests are already on their way at this point.
Yellow panels are useful indoors all year round [Photo: Johannes Ziegler Photo / Shutterstock.com]
The boards are available in a wide variety of sizes. In addition, the special glue does not start to run off if the temperature should change – and with the 40 glue boards that you receive when you order our Plantura yellow boards, you are well equipped for a longer period of time.
Yellow boards for pest control
With yellow boards it is possible to monitor an infestation and in some cases also to decimate the number of insects. Our Plantura yellow boards catch the following insects, for example:
- Winged aphids (Aphidoidea)
- Whitefly or greenhouse whitefly ( Trialeurodes vaporariorum )
- Sciarid gnats (Sciaridae)
- Thrips (Thysanoptera) – especially the vine thrips
Furthermore, yellow panels are attractive to fruit flies ( Drosophila ), leaf miners (Agromyzidae ) and the green leaf hoppers (Empoasca vitis).
Yellow tablets, for example, have a strong effect on the whitefly [Photo: D. Kucharski K. Kucharska / Shutterstock.com]
Of course, you can also use the yellow panels indoors for house plants and not just in greenhouses and outdoors. Because fungus gnats in particular often cause problems in living spaces. You can find more information on how to fight sciarid gnats here.
Yellow panels help to identify an infestation very early. This allows them to start fighting right away and contain the infestation before it becomes a real problem. In addition, the sticky boards show the success of the control. However, the sticky tablets are not a means of combating insects. A few animals always escape the traps and can continue to reproduce, and the actual damage is often caused by the insect larvae that live underground.
Yellow panels give a good overview of the development of the number of pests [Photo: Catherine Eckert / Shutterstock.com]
Use yellow tables correctly:
In principle, one yellow board per flower bank or one board per square meter is sufficient to monitor pest infestation. Make sure to distribute the yellow panels evenly over the infested area. They are usually effective for a very long time, so they rarely need to be replaced. Our Plantura yellow bars, for example, work for at least six months.
Tip: If the pest pressure is very high and the yellow board is full of insects after a very short time, then it is advisable to put more boards between your crops and replace them earlier for a successful use.
Yellow signs as a danger for beneficial insects?
Bees, ladybugs and the like rarely get lost in the house or greenhouse, so the risk of accidentally catching beneficial insects is relatively low. On the other hand, it looks different when it is applied outdoors. You should therefore carefully consider its use here, because it ultimately cannot be avoided that some useful insects or even small birds are caught there.
Tip: The use of yellow boards is one of the few methods that can be used to prevent cherry vinegar flies from laying eggs in cherries. When using it, it is important to really only leave the boards in the tree for the short flight period of the flies between May and June and to remove them immediately afterwards. This prevents too many unwanted animals from sticking to the traps. We have summarized more about their detection and control in a separate article on the cherry vinegar fly.
When used outdoors, there is a high risk that beneficial insects will also fall into the trap [Photo: andras_csontos / Shutterstock.com]
Make yellow boards yourself
Yellow tablets are of course available in stores, but you can also make them yourself. Simply take yellow construction paper and laminate it. Use a punch to punch two holes in the boards through which you can stick a chopstick or wire for hanging. You can coat the surfaces of the yellow boards with a sticky mass. There are several possibilities for this:
- Insect glue: You can buy this ready-made in tubes and also use it for self-made glue rings. One tube is sufficient for around 200 commercial size yellow tablets if it is applied thinly.
- Sugar glue : dissolve about three parts sugar in two parts water and bring this mixture to a boil. After the liquid has started to boil, do not stir any more – otherwise the sugar will later crystallize in crystals and will not stick. Preserving takes a little practice: The sugar mass should be boiled until it has reached a temperature of 105 to a maximum of 115 ° C. Once this temperature has been reached, the cooking process must be stopped immediately by placing the pot in a bath of cold water. Even now, the mass must not be stirred until it has cooled down completely.
- Insect glue according to Uroma's recipe : 200 g lard are heated with 200 g rosin in a water bath and stirred until they have mixed well. Then 200 g of brown soft soap are stirred in, everything is poured with 2500 g of rapeseed oil and stirred until the liquid has cooled down.
Tip: The glue according to Uroma's recipe does not always work because the materials differ in quality and the right temperatures during the mixture are very important. This recipe is therefore more for hobby gardeners who enjoy such experiments.
Sugar and water are enough to make your own glue for yellow bars [Photo: ffolas / Shutterstock.com]
With one of these three recipes you can easily make your own yellow bars – in the desired quantity and size. To reuse the yellow boards, simply scrape the trapped insects off the surface and apply a new layer of glue. Of course, you can also try other colors and color compositions. You can find out more about the different types of glue boards here. The blue tablet is a special form, attracting other types of insects than the yellow variant.