I missed your thread anyway the answer is use a pesticide that would kill these weeds. First of all keep the good plants away that are not affected by weeds. There is also solar insect killer that would really help you to keep plants safe.
What type of weeds do you have? any photos of them?
My plants got affected by white flies and some other bugs, as you suggested I did it. The plants that got effected had thrown in garbage, since didn't find any pesticide in the market.
I will be taking care from here onwards on such type of weeds and flies. Thanks for your suggestion, could you let me know any pesticides that are available online.