MSc

Studies on the epilachna beetle complex occuring on selected vegetable
crops were carried out at the College of Horticulture, Kerala Agricultural
University, Vellanikkara, Thrissur, Kerala during 1995-1997 to establish their
taxonomic identities. The morphology, biology and the natural enemy association of
these beetles were also studied.
Based on the male and female genitalial characters, the epilachna beetles
feeding on brinjal, bittergourd and cowpea were identified as Henosepilachna
vigintioctopunctata (Fabricius), Henosepilachna septima (Dieke) and Afidenta
misera (W eise) respectively.
The salient features to distinguish between these three species are the
curvature of the apex of sipho which is a part of the male genitalia and the shape of
the female genital plates. The apex of sipho is curved outwards with a bluntly
rounded tip in both H. vigintioctopunctata and A. misera, while it is curved inwards
with a sharply pointed tip in H. septima. A semicircular notch is present on the
female genital plates of H. vigintioctopunctata, while there is a slit like notch in H.
septima. The notch on female genital plate is absent in A. misera.
It was confirmed that the beetles are highly host specific.
Henosepilachna vigintioctopunctata showed a strict host restriction to solanaceous
plants, while H. septima and A. misera are restricted to a few cucurbitaceous and
leguminous plants respectively.


There was not much gross morphological variations between the species
except for their body size, H. septima being the largest and A. misera the smallest.
The different spot variants met within the species by the variations in elytral
maculation was found to be a morphological character only. Though the grubs of
the three species are similar in external appearance, they can be easily distinguished
by the structure and sclerotisation of the scoli on body surface and the details have
been discussed. The three species showed similar biological attributes with a life
cycle period of 25.25, 2l. 59 and 24.76 days for H. vigintioctopunctata, H. septima
and A. misera respectively at 27.6°C and 89.5 per cent relative humidity. Under
. field conditions, the grubs and pupae of the three species were parasited by
Pediobius foveolatus (Crawford) (Eulophidae:Hymenoptera) and the egg masses
were parasitised by Tetrastichus ovu/orum Ferriere (Eulophidae:Hymenoptera).