Abstract:
The biology of Siopsis species (Diptera; Diopsidae) and Epilachna
s im i l is (Coleoptera; Coccinellidae) was studied on the Acora P lain s .
of the three species of Diopais found, D. thoracica caused the most
severe damage to r i c e . AH the developmental stages of these insects
are described and keys are provided for identify in g a ll the various
stages of the Diopsis species. D. thoracica exhibits sexual dimorphism
with regard to the interorbita l distance. A high stalk infestation o f
forty -eight per cent was recorded in the major rainy season. The parasite and alternate host of these insects species are discussed. Artificial infestation of rice stalks with the larvae o f D. thoracica demonstrated
that a single larva, could destroy 3 - 6 stalks during its life
time leading to a loss of about nine percent in yield .
All the developmental stages o f B. similis are described and a
key provided for identify in g the four larval in s tars . Possible control
measures against the Diopsis species and Epilachna similis are discussed.