Antifeedant activity of plant extracts from Mentha piperita L. and
Mentha pulegium L. were tested against the Indian meal moth, Plodia
interpunctella (Hübner). The nutritional indices: relative growth rate
(RGR), relative consumption rate (RCR), efficiency of conversion of
ingested food (ECI) and feeding deterrence index (FDI) were measured
for first-instar larvae (15-d old). Treatments were evaluated using
a flour disk bioassay in the dark, at 25±1°C and 60±5% R.H.
Concentrations of 0, 0.1, 0.5, 0.75, 1, 1.5 and 2 mL/disk were prepared
from each essential oil. After 72 h, nutritional indices were calculated.
M. piperita oils were more effective than M. pulegium oils, by significantly
decreasing the RGR, RCR and FDI. At the highest concentration
tested (2 mL/disk), the ECI (9%) was significantly reduced.
