Insecticidal composition

A method for combatting insects by inhibiting the development of the larvae, or pupae, thereof which comprises treating, by contact or ingestion, an immature form of said insect with a development inhibiting amount of a compound of the formula ##STR76## wherein R.sub.1 represents hydrogen, halogen, C.sub.1 -C.sub.4 -alkyl, vinyl or ethynyl,

• R.sub.2 represents hydrogen, halogen, methyl or ethyl, or
• R.sub.1 and R.sub.2 together represent the cyclopentyl or cyclohexyl ring,
• R.sub.3 represents hydrogen, halogen, methyl, ethyl or C.sub.1 -C.sub.4 -alkoxy,
• R.sub.4 represents hydrogen, halogen or methyl,
• R.sub.5 represents hydrogen or halogen, or
• R.sub.3 and R.sub.5 together represent a carbon-carbon bond,
• R.sub.6 represents hydrogen, methyl or ethyl,
• R.sub.7 represents cyclohexyl or the group ##STR77## R.sub.8 represents hydrogen, halogen, C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy,
• Y represents oxygen, or the group ##STR78## whereby the ##STR79## is bound to the phenyl ring, Z represents hydrogn or methyl, and
• m and n each represent the number 0 to 1.