Synergism of permethrin and d-Limonene against household and stored product insects.

Synergism of cis, trans and technical grade permethrin with
d-limonene, a cheaper and safer plant product, was studied
separately against houseflies and stored product insects. Individually,
cis and trans permethrin did not show synergism
but the technical grade permethrin, which was a mixture of
cis and trans isomers, was synergised 4 to 5 times. These
findings suggest that the behaviour of individual stereoisomers
and of their mixtures towards a foreign compound,
a synergist, can be different.