General gardening topics

The Phormium mealybug pest and how to treat it

Last updated on April 28th, 2022

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The Phormium mealybug is a pest that originates from New Zealand and is able to thrive in the UK outside, even in the winter, which is unusual because all other types of mealybugs you will usually find in greenhouses because they need a warm temperature, but not the Phormium mealybug.

Most mealybugs are a problem because they remove the sap from your plant, this can affect their growth rate and then they excrete excess sugar onto the plant when they leave, which is called honeydew. The honeydew lands on the leaves and the stems and gets colonised by sooty mould which then turns the surfaces of your leaves black.

The mealybugs themselves are like small woodlice that are pale in colour, but you usually notice the fluffy white wax first.

Mealybug can be very damaging, especially on young plants but older established plants can usually live with the problem and it often goes unnoticed.

The insects usually cluster at the base of leaves and cause a heavy infestation. This depletes your plant vigour and causes the foliage to die off prematurely. If you have an older, more established plant it might be somewhat more tolerant and survive without a lot of damage.

How to try and control mealybug

It can be very difficult to control these insects because they get concealed at the base of leaves or at the margin where different leaves fold together. This can make it difficult to reach them if you spray a pesticide over the tops of the leaves.

Unfortunately, there are very few products that give you, as a home gardener, any level of control. However, there is a product called Provado bug killer that is a systemic insecticide, this means it’s taken into the plant’s system and poisons the mealybug when they suck the sap from the plant.

Provado 30 ml Ultimate Bug Killer Concentrate
  • Makes up to 60 litres.
  • Fast acting formula.
  • Contact insecticide that protects for up to 4 weeks.
  • Kills most common insect pests on an extensive range of ornamental plants.

Prevention is key

  • The best steps are preventative. Make sure that you examine your Phormium carefully before you purchase it, and avoid any plants that show even the slightest sign of a mealybug infestation.
  • If you have plants that are very established, they might tolerate a light infestation and survive just fine so you won’t have to do much.
  • If you have a heavily infested plant, particularly a younger plant, it might be best to simply replace them. You can sometimes divide a plant and then replant a section that doesn’t contain any mealybugs.

Last update on 2024-07-13 / Affiliate links / Images from Amazon Product Advertising API

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