I think linear exponential or log-probit analysis is best way to determine the LD50 of tested compounds using Finney's method.

http://www.jpharmsci.org/article/S0095-9553(15)32712-8/pdf

If the objetive of your study is to evaluate the efficiency of the insectide over the initial test organism, what if you eliminate the offspring as soon as they born?

In that thought, you can do this at the time of the daily prophylaxis and evaluation of accumulated mortality, both in the control and insecticide treatments. Then you apply Schneider-Orelli's considering only the adults mortality.

Best wishes,

Paulo Cremonez.

Dear Paulo,

Please contact Pr. Malik LAAMARI a specialist of Aphids. It exist in researchGate.

Best wishes Noureddine Soltani

You can use the SPSS 20 for calculating the LC 50 for certan insecticide.

Please see the following arcticle.

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

Dear Pr. Soltani

Thanks for your contact. Sure I'll contact Pr. Laamari for consult any doubts me or my co-workers have about aphids. Of course Dr Steinwender question could be delegated to him.

Best regards to y'all,

Paulo Cremonez.

I highly recommend the opinion of Paulo Gimenez because you do not investigate the latent effect of the pesticides used  

Yes, I agree. I also thought about eliminating the offspring. The argument however could be that the effect of the insecticide is quite weak if it kills the adults but there are still 40 offspring left (even if in reality 100 of them died in total). Hence I was wondering if there is a way to normalise the proliferation in the control to the treatment.

Don't use adults for your studies. Use Nymphs and shorten the time of experimentation. 

Dear Berndt,

You have not mentioned some important data influencing the assessment and the outputs of your experiments: what was the aim of your experiment (LD or LC50 value is only a detail), you have laboratory or field experiments, what about the mode of action of the insecticide and so the rapidity of the preparation’s efficiency, is it a contact insecticide acting thorough surface residues or a systemic or translaminar preparation?

Many mentioned probit analysis by Finney as a reliable statistical method. There are many programs for it. In lab experiments, generally the Abbot formula works well, the others are mostly used in field experiments when the number of testing animals cannot be preset. Also you can do not to consider the offspring but in case of an insecticide development project, it is not a solution.  The duration of the test may be considered as some mentioned it earlier. I think you should try both, longer and shorter assessment time in order to find the acceptable solution.  I have assessed efficiency of some insecticides on aphids but – fortunately – reproduction did not influence the results because of the very rapidity of the mode of action. By the way, the incidental offspring were killed as well.

Dear Bernd,

You have not mentioned some important data influencing the assessment and the outputs of your experiments: what was the aim of your experiment (LD or LC50 value is only a detail), you have laboratory or field experiments, what about the mode of action of the insecticide and so the rapidity of the preparation’s efficiency, is it a contact insecticide acting thorough surface residues or a systemic or translaminar preparation? Many mentioned probit analysis by Finney as a reliable statistical method. There are many programs for it. In lab experiments, generally the Abbot formula works well, the others are mostly used in field experiments when the number of testing animals cannot be preset. Also you can do not to consider the offspring but in case of an insecticide development project, it is not a solution.  The duration of the test may be considered as some mentioned it earlier. I think you should try both, longer and shorter assessment time in order to find the acceptable solution.  I have assessed efficiency of some insecticides on aphids but – fortunately – reproduction did not influence the results because of the very rapidity of the mode of action. By the way, the incidental offspring were killed as well.