| Well, if these white things are alive then it is very likely your plant suffers from some kind of insects of the family Coccidae or Eriococcidae. But be careful, if these white things are not really alive then it may be the skin that has been shed from Aphids which is also sticky as the previously mentioned insects. What you have to do?
If it is really Aphids then Diazinon may have done the trick and killed them(if sprayed properly to the entire plant)
But if these are Coccidae then it may have not killed them(the most possible) Have a look on the plant to see if there are still alive creatures on it.If not, don't bother further. If you do see something then Dimethol(Dimethoate) would be your best choice.
Be careful, it's toxic.Wear gloves when spraying and leave the place as soon as possible.It's gonna sting for a while there. Go buy a small bottle since you need only a tiny amount of that insecticide. Good luck ps: to strengthen the plant you can water it with 5 drops of Iodine(diluted in water) | 
