White spots on houseplants may look harmless, but they are actually “thrips” – tiny larvae that can develop into very troublesome pests if left alone.
You should be especially careful now if you find crawlers on your indoor plants; Because it is during winter that they thrive in your room.
Absorbs the life of the plant
– A plant lover's biggest fear is insect attacks on plants, if any type of insect spreads and many plants are attacked.
So says Anders Røyneberg, agronomist and author of the books “Plantelykke”, “Plantebonanza” and “Livsnyterhagen”.
In the spring, she will publish her fourth book, “Crucadilla – Everything You Can Grow in Jars and Boxes” and on her Instagram account. @Arctic Gardener He has thousands of followers.
A plant lover, that is. Who knows how much trouble thrips can cause if they attack your potted plants.
Thrips feed on plant sap, often sitting under leaves, literally sucking the life out of the plant. They lay eggs in plant tissue, bark cracks and directly on the plant, where the eggs are almost invisible until they hatch.
This is according to gardeners Merethe Bråthen and Elin Nordli at Plantasgen.
– Thrips gradually grow from tiny larvae to short little animals that can be light brown to black in color. Sometimes you can see small animals with bright larvae, says Nordli.
Thrips can be 0.5 to 14 millimeters long, flying insects. In this way, they spread easily to other potted plants.
You bring them in
If the leaves of the potted plant become discolored, yellow or gray, this may be a sign of a thrips attack.
– If the leaves are torn off or a branch is broken on the plant, the damaged part is the first to be attacked by insects. That's why it's a good idea to remove damaged leaves, yellowing leaves, or cut off broken branches, says Reinberg.
A common reason for thrips to appear in your home is when you purchase new plants that have thrips-like pests. This way, according to the expert, you “import” them with you.
Thrips can live in nature and therefore fly through windows and doors.
Indoors in winter
Although thrips live well year-round, you may have many of them on your indoor plants, especially in the winter.
– Thrips thrive in heat and reproduce easily when indoors at good temperatures. Temperature is decisive for how big the attack will be; The warmer it is, the more eggs are laid, and the faster the development from egg to adult, Brathan says.
Reinberg has also experienced that the problem often worsens in the winter.
– Hard to be a houseplant in Norway in winter. I call them the “trimester of death.” The months of November, December and January are less light and more dark. Light is food for plants, and in winter, plants “starve” because there is so little light available, he explains.
– During these months, the plant is most vulnerable, weak and susceptible to attack by thrips, so even if the plant has thrips in the summer months, they will bloom again in full force in the winter, says Reinberg. .
It's unusual for thrips to feed on fruit because they prefer plant sap from flowers and leaves, Bratton and Nordley assert.
– but it cannot be ruled out that under certain circumstances they may also attack fruit on a plate. But in that case eating the fruit is not dangerous, gardeners insist.
Reinberg's plants were attacked by thrips several times, so he gradually took several measures, which have a preventive effect:
– Check the leaves carefully when buying, spray them with green soapy water before placing the plants in your house, provide regular fertilizers and nutrients, and cut dead and damaged leaves, he says.
Also, he, Brathen, and Nordley have the following tips:
- Make sure the plants get enough light during the winter months. It is better to choose plant bulbs with white light.
- Feed your plants with liquid plant food or compost sticks – this produces healthier and stronger plants that are less susceptible to attack.
- Cut off damaged branches and leaves.
- Because thrips can fly indoors from nature, plants near windows or doors should be moved indoors during the summer months.
- Choose plants that are susceptible to thrips, for example: mother-in-law's tongue, yucca palm, sailor's comfort, emerald palm, cactus, porcelain flower, succulent and cactus.
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