Abstract:
In the wet zone of Sri Lanka, a field experiment was conducted to study the population dynamics of the sugar cane planthopper (Pyrilla perpusilla). The numbers of eggs, nymphs and adults were high in July, August and Oct. 1993, April and Sep. 1994, and Feb. and March 1995. Population size showed a negative correlation with rainfall and humidity and positive correlation with minimum temperature. A hymenopteran parasitoid (Parachrysocharis javensis) and 9 species of predators of the planthopper were recorded in the plot. The main factors responsible for the fluctuation of the planthopper population were the egg parasitoid, the predators and the amount of rainfall.
