Red Spider Mite Sachets

Dear Lynn

I received my red spider mite killer sachets on 3/10/12 and hung them immediately on my conservatory plants - in particular on a phoenix robellini palm. How long should it be before I see a reduction in red spider or in fact anything emerging from the sachets? To date I have seen neither and my palm is looking increasingly distressed by the red spider.



Dear David

The Amblyseius mites inside the sachets are tiny about 1mm long so are difficult to see with the naked eye. The sachets are slow release so the mites are not all released at once,  enough mites will be released to consume 5 adults or 25 young larvae/eggs per day and will remain active for 2-4 weeks so you should start to notice a reduction in red spider mites soon.

There are certain parameters which should be adhered to for the Amblyseius predator sachets to work:- 

  • requires a temperature of 16°C (64°F) but below 30°C.
  • should be introduced to the greenhouse/conservatory on the day of receipt.
  • are sensitive to long hot dry spells, so damping down or misting can help at these times.
  • the sachets should not be placed in direct sunlight or near to heating pipes.
  • remember that biological controls are living creatures and can be effected by chemical usage. If you've used any persistent pesticides recently this could have caused the mites to fail.

Do you have a heavy infestation of red spider mite and do you have webbing present?  If so break the webs to give the mites a helping hand  it also helps to increase the humidity by spraying the underside of the leaves.  You can also group infected plants together so the mites can jump from plant to plant.

It would be a good idea for you to have some Savona Insect Killer Spray handy for future use to control red mites which have just emerged from hibernation (and are tough for predators to eat) before introducing the Spider Mite Killer Sachets at the first sign of mites next year.

Hopefully you should see some improvement soon however please be aware that the spider mites may have affected your plant and it will take a bit of time for it to recover especially as this is the end of the growing season.  It is also a possibility that something else is going on with the plant too.  If you feel this may be the case please feel free to Email me a photograph in order for me to advise further.

Kind  Regards

Lynn Burton
Horticultural Adviser