Software to calculate probit analyses according to Finney (1971), Which is used to illustrate the relation between stimulus and response in toxicological and biological studies.
Illustrate dose-response regression line

Control correction

In this page, you can calculate corrected efficacy % according to Abbott, Henderson & Tilton, Schneider-Orelli or Sun-Shepard formulas.

  • There are 4 formulas available to calculate corrected efficacy % in pesticide trials.

  • The selection of appropriate formula is depending on two factors:
    1-Trial condition (infestation or population stability and homogeneity).
    2-The data in your hand (live individuals or mortality %).
    The following table will help you to use the right formula.

Available data

Non-uniform
population

Uniform
population


Infestation or
live individuals

Henderson-Tilton

Abbott


Mortality

Sun-Shepard

Schneider-Orelli



Henderson-Tilton's formula

Corrected % = (1 -

n in Co before treatment * n in T after treatment

n in Co after treatment * n in T before treatment
) * 100
Where : n = Insect population , T = treated , Co = control


Population in treated plot before treatment

Population in treated plot after treatment

Population in control plot before treatment

Population in control plot after treatment

 


Reference:
Henderson, C.F. and E. W. Tilton, 1955.  Tests with acaricides against the brow wheat mite, J. Econ. Entomol. 48:157-161.


Abbott's formula

Corrected % = (1 -

n in T after treatment

n in Co after treatment
) * 100
Where : n = Insect population , T = treated , Co = control


Population in treated plot after treatment

Population in control plot after treatment

 


Reference:
Abbott, W.S. (1925). A method of computing the effectiveness of an insecticide. J. Econ. Entomol.; 18 : 265-267.


Sun-Shepard's formula

Corrected % = (

Mortality % in treated plot + Change % in control plot population

100 + Change % in control plot population
) * 100


Mortality % in treated plot

Change % in control plot

 


Change % in control plot population = (

Population in control plot after treatment - Population in control plot befor treatment

Population in control plot befor treatment

) * 100


Reference:
Püntener W., 1981 Manual for field trials in plant protection second edition. Agricultural Division, Ciba-Geigy Limited.


Schneider-Orelli's formula

Corrected % = (

Mortality % in treated plot - Mortality % in control plot

100 - Mortality % in control plot
) * 100


Mortality % in treated plot

Mortality % in control plot

 


Reference:
Püntener W., 1981 Manual for field trials in plant protection second edition. Agricultural Division, Ciba-Geigy Limited.