OBSERVATIONS ON THE BIOLOGY AND HOST-SPECIFICITY OF PAGIOCERUS-FRONTALIS (FABRICIUS) (COLEOPTERA, SCOLYTIDAE) AT 20-DEGREES-C AND 25-DEGREES-C AND 75-PERCENT RH

The biology of Pagiocerus frontalis was investigated at 20 degrees C a nd 25 degrees C. Three larval instars were observed. The egg to adult development lasted 4 weeks at 20 degrees C whereas at 25 degrees C it required 3 weeks. Out of the food substrates tested, only maize and ca ssava chips proved to be favourable media for the development of P. fr ontalis. Comparisons at the two temperatures mentioned above, and popu lation studies revealed a higher population density at 25 degrees C in all the maize cultivars rested. Varietal differences amongst the maiz e tested were observed. Maize cultivars with soft grain characteristic s were more susceptible compared to those with hard grains.