The first reported examples of C-terminal aldehyde analogs of an insect neuropeptide are described. They are hexapeptide insect kinin
analogs Boc-VFFPWG-H and Fmoc-RFFPWG-H. Activity observed for these modified analogs in an in vitro insect diuretic assay confirms
that the C-terminal aldehyde group is tolerated by an insect kinin receptor. The two analogs demonstrate greatly enhanced activity over
standard C-terminal amide insect kinins in a larval weight gain inhibition assay in the corn earworm Helicoverpa zea. Treatment with
Boc-VFFPWG-H led to significant increases in larval mortality at doses of 500 pm (45%) and 5 nm (67%). Boc-VFFPWG-H represents
a lead analog in the development of novel, environmentally friendly pest insect management agents based on the insect kinin class of
neuropeptides.