Whitefly on mint plant

Dear Julian

I am trying to find a way to get rid of white fly on my mint plant. (unfortunately I don't know what type of mint it is). I think it is white fly, they are like 2mm white butterflies. There are also a light green/grey thin insect about 3mm that has appeared about the same time. The mint leaves have white marks on them. Please see attached photograph.

The plant is growing outside in a hanging basket with a flat side against the house wall. It is a very sheltered patio and the mint doesn't get much water even when it rains. It gets sun in late afternoon and early evening.

I have read about encarsia formosa but this seems only for greenhouse plants. Can I use them outside?

If I can use it, how much would I need for one plant and how often would I need to use it?

Whilst I have white fly are the mint leaves unsafe to eat?

Any suggestions welcome. I love growing my own mint and don't want to loose it.

Kind regards

Rebecca Law  

Dear Rebecca

Sorry for the delay in reply to your e-mail.

Encarsia formosa do not work outside very well, as they are specific to glasshouse whitefly. However I think the Mint might be under attack from Mint aphid (they do leave skins on the plant that look like whitefly). I would suggest you use the pyrethrum based spray; Insect Killer spray from Harrod Horticultural.

This has a wide knock down effect on many soft bodied insect pests. It is also safe to use on edible plants, just leave the mint 24 hours after spraying before eating. The pyrethrum breaks down naturally and is used in organic gardening. Spray once a week to break the life cycle and make sure you get a good coverage over the mint.

Hope this helps.