Thrip are small, winged insects that lay their eggs inside the leaf tissue. Because of this, they can be more difficult to treat.  Larvae are a yellowish color and are quite small.  Adults turn a dark color, nearly black, and develop wings.  They puncture the leaf tissue to eat the chlorophyll  and can transmit diseases amongst plants.

Signs and symptoms include discoloration, abnormal or stunted growth, loss of leaves and black, pepper-like particles on the leaves (their excrement).

Thrip can be absolutely detrimental to your houseplant collection, as they can spread rapidly and destroy plants very quickly.  

As destructive as they are, they can be treated, given you are persistent and use the proper solutions.
You can either purchase and use a commercial solution that treats Thrip  such as Dead Bug Brew, or Insecticidal Soap solutions, (both found to be effective) or you can follow our At Home Recipe for a non-insecticidal alternative you can mix up and use.

Using a 16 ounce water spray bottle, combine 12 ounces of water, 4 ounces of 92% Isopropyl Rubbing Alcohol and 2 tablespoons of Dawn Dish Detergent.  You can use other dish detergents, if you do not have Dawn, but we find that the classic, blue Dawn is the best.  
If you can not find 92% Isopropyl Alcohol, you can use 70%, however you will want to alter your solution to 10 ounces of water and 6 ounces of Isopropyl Alcohol.  Do your best to find the 92% though, as we find that they stronger isopropyl is much more effective.

With this solution in the spray bottle, thoroughly spray your entire plant.  Be sure to cover both the top and undersides of the leaves, all stems and branches, and pay close attention to any new growth areas. 
Because these pests can reproduce so quickly, you will have to spray your plant every 2-3 days for 2 weeks to ensure that all adults, larvae and eggs are killed and you stay ahead of them.
It is good practice to wipe the leaves of your plants clean after 2 or 3 treatments have been applied.  This will remove any dead adults, larvae and eggs.  This can be done with a wet paper towel.  There is no need to completely rinse your plant off after full treatment. 

There is some risk in treating any plant with any insecticide or non-insecticidal treatment.  You may notice some leaf browning, wilting or loss of leaves.  This should correct itself relatively quickly, once the infestation is taken care of, and your plant is allowed to grow without hinderance. 

If you have any further questions or need more assistance, please feel free to reach out to us.