220 P. R. Shashank et al.
31.86 retention time, which was almost similar to
E10-16:Ald. In this case, there were many small
peaks which overlapped on specific peak. Thus,
GC analysis indicated the presence of major
pheromone compound in both populations.
Host—Plant Interactions
Egg incubation period (in days) was the least
(2.67 days) on spineless spike castor as also the
larval period (26.68 days) compared to compact
spiny and spiny loose castor types. The trend in
the egg incubation, larval and pupal periods was
consistent across three castor types. Conogethes
larvae preferred compact spiny castor type for
feeding over other two types. Conogethes larvae
and pupae gained more weight on compact spiny
castor type than on the spineless and spiny loose
castor types. This is obvious because compact
spiny type was more suitable to Conogethes than
the other two castor types. There were statisti-
cally significant differences between the spine-
less spike and spiny loose spike types and the
compact spiny types at 1 % ( p < 0.001) level of
significance. Female pupae weighed more than
the male. Studies on the biology of Conogethes
on castor and cardamom revealed that the insectFig. 7 Gas chromatogram (GC) of female abdominal extracts of Conogethes breeding on castor (60 FE; arrow, peak at
which E10: 16Ald activity was detected). (Shashank 2012 )
Fig. 6 Gas chromatogram (GC) of synthetic E10:16Ald (Retention time indicated). (Shashank 2012 )