Dear colleague,

this question is very extensive. You must know all about your insect object, its biology, developmental stage, ecological features to understand what is changing after pesticide impact. Find the attached file from BASF and references:

http://www.irac-online.org/teams/mode-of-action/

http://www.epa.gov/caddis/ssr_ins_int.html

Dear Chikaodili and Galina,

I think the MoA of a pesticide can also be determined once the active ingredient of the pesticide is known and using the IRAC MoA which you suggested.

Primarily mode of action can be decided based on              

1. Site of action(nervous system, cuticle, respiratory system, energy production system)

2. Mode of entry

For indepth details you need to go through text books or link provided by latter friends 

Dear colleague,

There are several classes of insecticides according to their chemical structure or target sites. If the active ingredient is known and commercialised, you can find some basic technical informations (formulation, activity, spectrum, mechanism of action....) on the considered product (manual of pesticides, Firmes...). In further appropriate experiments you can confirm this mode of action (neurotoxic, inhibitor of chtin synthesis, moulting accelerating compounds...). Because  environnemental concerns it is preferable to work on insecticides with selective mode of action. I  recommend for you to see recent reviews on the subject of Smagghe (exist in researchgate) or Dhadialla.  

Best regards Pr. N. Soltani

Observation of  blood cells and nerve function  may be primary step for this study

Dear colleagues,

We must have additional information on this product. Neurotoxity activity can be easy appreciate by measurement of AChE.

Best regards

Although you did not specify the type of insect or the species of the insect and the actual pesticide you intend to work on. However, basically there are  a lot of information on mode of action of different categories of pesticides particularly on the labels of any pesticides based on their chemical structures, chemical components i.e active ingredients, pesticide target, formulation, activity, spectrum, mechanism of action, methods of application of pesticides. In summary, get laboratory manual to help out, specifically WHO assessment and evaluation manual on pesticides.   

Many article or book explain about mode of action the pesticide, depend on the group of pesticide ie. organochlorin, organofosfat, carbamat, pyretrhoid etc The MoA likes nerve poison, hormonal disruption or insect grouth regulator etc.

Danar Donor is very correct.

Dear colleague,

I recommend for you to see the  recent publication attached:

SPARKS T.S. & NAUEN R., 2015. IRAC: Mode of action classification and insecticide resistance. Pesticide Biochemistry and Physiology,121: 122-128.

You can find some recent statistics on pesticides and particularly a classification of insecticides according to their MoA. There are 25.

Kind regards

Prof. N. Soltani