Thrips - Thunderflies


Tetranychus urticae


Thrips are small, tubular-shaped flies that'll bring great destruction to the unfortunate plant(s). They can be introduced into the home via many different methods, but most notably being through an open window or via infected soil during a transplantation. Despite their damaging destruction, they can be easily eradicated using the correct methods which will be discussed below.


Top Tips & Info

  • Eradication Difficulty - Moderate
  • Life Cycle - Up to thirty days.
  • The female can lay up to ten eggs per day - one hundred in total.
  • Thrips will prance along the plant's flat surfaces, meaning that pretty much all parts above the soil line can be affected.
  • Remove and crush each visible bug and larvae using your fingers or a damp cloth.
  • Prune off the worst affected leaves and any flowers that house the infestation.
  • Take the plant outside and perform a gentle hose-down. Aim at all of the cubbyholes and leaves for complete obliteration.
  • Replace the top quarter of the soil with a fresh best of the appropriate compost while it's drying off.
  • Once dry, spray the foliage using either an organic, or chemical-based pesticide. (The latter is recommended for Thrips).
  • Repeat the wiping, hosing-down and pesticide steps every 7 - 14 days, until there are no signs of an infestation for several weeks.
  • It's mandatory to quarantine the affected specimens into another room to avoid further spread during an attack.




Symptoms

You'll first notice the yellow, egg-like larvae appearing on the top sides of the foliage. After a few seconds of inspection, minuscule black and white flies will be parading over the whole plant, including the soil, stem and flowers. Yellow, dark patches will quickly develop within the next few days once an infestation takes over. Thrips can be a very damaging pest as they'll scrape the cell membranes off from the leaf - action must be taken immediately for the prevention of death.

Before we go into the remedies for addressing this pest, have a quick look at the neighbouring plants to see if they've become under attack, too. Thrips are very contagious, so the likelihood of multiple specimens sharing the infestation is pretty high.




Susceptible Plant Parts

Both sides of the leaves, but mostly on the top-side. They tend to attack middle-aged growth and will quickly destroy new growth.




Actions Required

1. While using a damp cloth, destroy as many bugs and their larvae as possible. Any flowers must be removed along with the worst affected leaves or stems. 

2. Take the plant outside and GENTLY wash the stem, leaves and each cubbyhole using an outdoor hose. It's important to spray in at least three different angles to ensure thorough administration. 

3. While the plant is drying-off, remove the top quarter of the soil in favour of a fresh batch of the appropriate product - Cactus compost for succulents, tropical plants for houseplant compost, etc. It's vital to replace the soil, as once summer arrives the larvae will hatch and wreak havoc on the hosting plant. 

4. Perform a final hose-down before placing it in a warm room, away from other specimens to dry-off. If the temperature is above 15℃ (59℉), keep it outside so that natural predators, (like ladybirds and green lacewings) can have a go at the critters. 

5. Once the specimen is bone-dry, it's time to administer a pesticide. Although there is a choice between two options (organic or chemical-based sprays), ukhouseplants would highly recommend using the latter option, due to the pest's ability to bypass organic varieties.

6. Keep the affected plant away from others in a quarantined room until the symptoms have subsided for at least four weeks. Always be wary of a relapse, and keep an eye out for possible outbreaks for several months after the last sighting.


N. B. - Although you should perform the wiping and hosing-down process BEFORE each pesticide application, you can wash the foliage at any given time to keep the infestation under control.



Organic Pesticides

Neem Oil is used across the world, and for a good reason. Not only is it accessible in many stores, but it'll also get to work after the first application. Dilute the liquid, (to the manufacturer's recommended strength) with water and/or dish soap and spray thoroughly onto the foliage and its cubbyholes. Any flowers must be removed instead of misted, due to the heightened chance of another infestation lurking in the background.

Insecticidal or Horticultural Soap is another popular pesticide on the market, and there are three versions to consider. The first way is by purchasing an RTU (ready-to-use) spray bottle, which can be immediately used on the plants. Although most garden centres will stock this, it's far more economical to purchase the second option - concentrated bottles. This method comes with pro's and con's but is far cheaper to use if you have multiple infestations. It's self-explanatory and highly beneficial for the outbreak as long as you use the correct levels of dilution - the only downside is its availability in local centres. It's best to buy this option online as there are many different companies to choose from, with some being cheaper than others. The final and most affordable way is by making it yourself;

There are three ingredients in creating your own insecticidal soap - a vegetable, tree or nut-based oil, non-fragrant dishwashing soap and tap water. Most oils are acceptable, with the most successful being vegetable, sunflower, neem and olive oil. Add two parts oil, one part dishwashing soap and eight parts water to create the dilution. Although it's best to fresh bottled water, tap water that has been allowed to sit for 24hrs will also be fine. Spray the dilution thoroughly around the plant, empathising both the infestations and the potential-hit areas. This method must be performed weekly over a month or two, along with regular pest inspections - as soon as you see a bug, crush it!

Natural Predators - The last non-organic method is by acquiring adult ladybirds or green lacewings. Although buying insects may be deemed as cruel or inappropriate, it's a natural, and least time-consuming way to remove the pests. Many online stores will sell the insects, all at varying prices and quantities. Once you've obtained the predators, release them in different sections of the plant, favouring the most infested areas first. They'll make their way around your plant, digesting both the eggs and the adults, leaving you with a potentially pest-free plant. Keep the insects and plant in an enclosed transparent box throughout this period to increase the rate of digestion. Unfortunately, this method can take several days, if not weeks, to work and could even be unsuccessful, which is why other methods are favoured.

Click on the individual links to purchase Neem OilCinnamite, an Insecticidal Spray or natural predators like ladybirds or green lacewings.



Chemical Pesticides


The BEST chemical pesticide currently on the market for treating Thrips.


We'd recommend using 'Bayer Garden Provado Ultimate Fruit and Vegetable Bug Killer Concentrate', as it worked IMMEDIATELY after one application. It's a concentrated product, meaning that you'll have to dilute it with the appropriate amount of water. Spray both sides of the leaves, along with any cubbyholes that could house the infestation. Keep the plant away from other specimens once there are no signs of an outbreak for over a month.


If you're looking for something with even more strength, try an Isopropyl Rubbing Alcohol, which can be bought from many online stores. This pesticide will work immediately, killing the bugs within a few hours of contact. Follow the manufacturer's recommendations and repeat hosing the plant down and pesticide application steps fortnightly until the infestation has elapsed. Keep it well away from others until the plant is deemed safe.




Ways to Prevent an Attack in the Future

At the local plant shop or garden centre, regulate and inspect any plants that you wish to buy. Check around the hard-hit areas, for instance, the foliage and new growths, before considering the purchase. Most Thrip infestations come from already-affected plants, so always keep this in mind when increasing your plant-collection!

Keep the windows and doors shut throughout May and June, as this is the time that Thrips are most active.

Change the top layer of the soil when bringing any new plant from a shop. Replacing the top layer of the compost will remove any larvae that may have fallen in, or been deposited by a pest. ukhouseplants does this religiously whenever a new plant enters the house!

Regularly check for pests on your own plants. Although this may sound patronising, many gardeners forget to inspect their indoor specimens. As soon as you see a symptom, keep it quarantined and follow the steps above!



For any more questions or queries about Thrips, be sure to message us via this link or comment in the section below!