you can follow IRAC method

http://www.irac-online.org/teams/methods/

Dear Hareesha,

Firstly, you should fix what are the aims of your planned experiments or studies?

Dear Andras Sir,

 The Aim is to find out LC50 values for newer molecules.

For working out LC50 values against aphids, you can use the leaf dip or leaf disc-cum-petiole dip bioassay procedures. The type of bioassay you choose, shall depend upon the kind of insecticide you are testing. For contact poisons, you can go for leaf dip method and for systemic insecticides you can use the second one.

Hi,

You can also use a Potter spray tower:

http://www.burkardscientific.co.uk/agronomics/spray_tower.htm

For aphid please see the following link:

and for the thrips see :

and for rearing and bioassays for aphid s also see :

https://www.youtube.com/watch?v=jE359LnpBnI&t=9s

https://www.youtube.com/watch?v=uS4H3t7LZWY

Article Bioactivity of Six Acetone Plant Extracts Against the Green ...

Follow IRAC method