New insect egg extermination manner and ovicide Characteristic constituent

摘要

A method has been found for protecting a crop by killing eggs of insects, or insects at the egg stage wherein the insects are detrimental to the crop. This method comprises applying to a locus where the eggs of insects are located or are expected to be located an effective amount of a compound of formula (I), or a salt thereof, R1-X-N(R2)-C(R3)=Z-R4 (I) wherein R1 represents an optionally substituted aromatic hetero ring containing nitrogen atom; X represents an optionally substituted alkylene or alkylidene; R2 and R3 represent hydrogen or optionally substituted alkyl; R4 represents a cyano or a nitro, and Z represents CH or N. The insect eggs which can be killed include tobacco budworms, pyrethroid resistant tobacco budworm, Mexican bean beetle or Colorado potato beetle.