Combatting pests with O,S-dialkyl-O-(4-phenylazophenyl)-thiophosphates
 Organophosphorus acid esters of the formula ##STR1## wherein R.sub.1 represents propyl or butyl; R.sub.2 represents methyl or ethyl; each of R.sub.3 and R.sub.4 represents hydrogen, halogen, or alkyl having 1 to 5 carbon atoms; n is a number from 1 to 4; and m is a number from 1 to 5. These compounds are useful for the control of insects, acarids and nematodes. 
Ciba-Geigy Corporation
A C
A01N C07F
inventional inventional
Alexis A. Paul L.
Oswald Valint