Division of Entomology and Nematology, Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore-560 089, Karnataka (India).
*Present address: Department of Zoology, Bangalore University, Bangalore-560056, Karnataka (India).
Scanty rains received during June-July, 1990 were found to affect population build up of Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), introduced for biological control of Parthenium hysterophorus L. (Asteraceae), in Bangalore. Laboratory studies showed that both burrowing of mature larvae and emergence of adults from pupal chambers required soil moisture, equivalent to 1.5 mm of rainfall. However, freshly formed adults were capable of surviving without emergence up to 12 days.
