What are these bugs on my citrus leaves? They crawl:

They look like spider mites to me, I have them as well on some of my trees. I keep them under control by spraying them with dish soap solution. I put about 1 tablespoon of dish soap into 1 litre of water in a spray bottle. You can also just wipe them off if you prefer. Good luck with the fight, when you think they've gone... they come back!

Then tomorrow I'll go and buy some pesticides, I don't want to spray with soap, because I want to get rid of them once and for all...

Or maybe it's aphid:
?

I have used soapy water in the past too, but the treatment has to be repeated frequently to keep the mites under control. I now use this to fight spider mites (see link below). After one application they are gone and I've never seen them again. Maybe you can find a similar product in your area...

http://translate.google.com/translate?sl=nl&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.ecostyle.be%2Fbladluizen_op_sierplanten&act=url

I use a product called "Actara" which contains tiametoxam. It helped me to get rid of mealybugs completely.

The red ones are spider mites, can't really see what is in the small photo. There are many products that will get rid of them.

as laaz said, those are spider mites. sometimes, it may be very difficult to get rid of them, as they can be quite persistent.

Evaldas,

my vote is for spider mites too. Pesticides are useless against them, you will need a miticide. There are reports that oil sprays are effective but I never had luck with them. You may wash them but they will come back... I used something called "lime sulfur spray" with good success.
This one: http://shop.horticultureguy.com/lime-and-sulfur-spray-594.html

Good luck!

http://shop.horticultureguy.com/lime-and-sulfur-spray-594.html

I find the horticultural oils easily controls spider mites (and aphids), usually with just one application. I have never had a failure obtaining a complete eradication using a horticultural oil. As with all treatments the success rate is directly proportional with how thoroughly the tree is sprayed. Spray the top and bottom of the leaves and all wood. Spray only in the EARLY morning or at dusk in the evening. - Millet (453-)

We don't have many products available here that you have available in your countries.
What about Neemazal?

I sprayed ALL my plants today following the instructions. I'm going to repeat the procedure next Thursday.

These Citrus Red Mites are widespread and difficult to control.
I have had limited results with horticultural oil, however carefully I try and reach every leaf. I also obtained a product based on Abemectin and this did work for a while. However, I was a bit scared about the side-effects of this chemical (and about the cost!) and in any case the pests soon seemed to become resistant.

The best solution I have found is a miticide called Bayer Spint or Bayer Masai. This is widely available from Dutch (Netherlands) websites at reasonable price and they seem happy to send overseas. I keep a small sprayer to hand in the greenhouse and spray individual plants whenever I see a red mite. They are dead the next day. Eggs and immature stages of the insect also seem to be controlled.

For example stockists
http://www.growshopholland.com/1112-bayer-garden-masai-spint-10g.html
http://www.moestuinwebshop.nl/index.php?p=32&cat=292