Even the grown plants also dying please help us by suggesting an idea.

Dear D Parameswara Rao It can be due to fusarium wilt caused by fungus OR it can be due to damage to the stem at the root level by some insect grubs. If the affected plant is can be easily pulled out , it is due to insect damage. Since it is one or two plants affected , you need not take any control measures. If the plant can be pulled out with some force , it can be due to fusarium fungi. If the pulled out plant is split open , you can see the middle portion darkened. Then it is fusarium wilt. If it is fusarium wilt, spray 3 gms Copper oxychloride in one litre of water. About 350 litres of spray solution may be required per acre. Please take care to use proper concentration of pesticides and also mix the pesticide with water outside the sprayer equipment for better results. Good luck