Harmful insects Houseplants

Answers to Your Questions: Thrips on African Violets

Question

I have a collection of African violets, about a hundred of them. This autumn I brought in my plants from outside and accidentally brought back thrips too. Now they’re everywhere! No matter how much I treat with a homemade insecticidal soap, I can’t get rid of them all: they keep coming back. I know there are systemic pesticides, but I don’t want to use these products, which are harmful to me and to the environment. Are there any natural systemic products? Or do you have any other tips?

Answer

First of all, thrips are tiny insects that scratch plant tissue, causing distorted growth. They spread to other plants by jumping and are difficult to control. In African violets, the most troublesome species is the flower thrips (Frankliniella occidentalis), which bore holes in the anthers, spreading yellow pollen everywhere.

Thrips are so small you can’t usually see them. If you blow on the flower, however, you should be able to see it move. Photo : Dave Kirkeby

The bad news is that, no, there is no systemic insecticide that is organic. There is, however, a way to suppress flower thrips without pesticides. Since thrips on African violets necessarily spend part of their cycle in the flowers, if you remove all the flowers and flower buds, you’ll eventually starve the thrips and prevent them from reproducing. However, you need to continue for 3 months, removing any flower buds as soon as you see them, if you want it to be effective. In addition, there must be no other thrips-infected plants in the vicinity. Although it’s sad not to see flowers for 3 months, imagine the profusion of flowers you’ll see afterwards, as your plants will store up their energy and bloom like never before at the end of the treatment!


Larry Hodgson published thousands of articles and 65 books over the course of his career, in both French and English. His son, Mathieu, has made it his mission to make his father’s writings accessible to the public. This text was originally published in Le Soleil newspaper on January 15, 2006.

Garden writer and blogger, author of 65 gardening books, lecturer and communicator, the Laidback Gardener, Larry Hodgson, passed away in October 2022. Known for his great generosity, his thoroughness and his sense of humor, he reached several generations of amateur and professional gardeners over his 40-year career. Thanks to his son, Mathieu Hodgson, and a team of contributors, laidbackgardener.blog will continue its mission of demystifying gardening and making it more accessible to all.

3 comments on “Answers to Your Questions: Thrips on African Violets

  1. Maryl discuillo

    Can she not use neem oil? Would you still need to remove all flowers? Just a thought

    • Mathieu Hodgson

      Neem oil is no longer approved on Canada as an insecticide. Even if it works, we couldn’t suggest it.

  2. And I’m encountering a group of locusts that regularly eat small flower bushes in front of my house. What should I do? Can someone give me advice?

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