Seasonal prevalence of the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) and its parasitoids in controlled and uncontrolled Citrus iyo groves in Ehime Prefecture, Japan

Abstract

Seasonal abundance and parasitism of the citrus leafminer, Phyllocnistis citrella Stainton were investigated in controlled and uncontrolled citrus groves from June 2001 through May 2002 on Citrus iyo (iyotangor) in Ehime Prefecture. No significant difference in mean monthly frequency of P. citrella infestation and its parasitoids was found between controlled and uncontrolled groves. There were two peaks of P. citrella infestation, in July and October. These peaks were strongly related to favorable temperature for P. citrella development and continuous flushing of new shoots. At least seven species of the parasite wasps of P. citrella were observed, of which Chrysocharis pentheus (Walker) and Sympiesis striatipes (Ashmead) were the predominant species. The population drastically increased from July to August, and also from October to November, which coincided with heavy infestation of P. citrella in the iyotangor grove. In spite of a high percentage of parasitism (about 70%) in summer and autumn, the damage to tender leaves was noticeable, because all native parasitoids attacked mature larvae and pupae of P. citrella after they had nearly completed their feeding period.