Diversity of Phyllocnistis citrella (Lepidoptera: Gracillariidae) parasitoids in citrus cultivars and the relationship with biotic and abiotic factors.
The diversity of parasitoids of the citrus leafminer, P. citrella, and its relationship with biotic and abiotic factors, were studied. Sampling was conducted every fortnight from July 2003 to June 2005 in organically managed orchards of tangerine (Citrus deliciosa cv. Montenegrina) and tangor (C. sinensis × C. reticulata cv. Murcott) in Montenegro, Rio Grande do Sul, Brazil. At each sampling occasion in 24 randomly selected trees, all leaves containing pupal chambers of the leaf miner were examined. In the laboratory, the leaf portion with the chamber was confined in a test tube and kept under controlled conditions until the emergence of the parasitoids or P. citrella. The number of shoots in the tree canopy was estimated for both sampling years. Ageniaspis citricola was the most abundant parasitoid, representing more than 80% of the total parasitoids in both cultivars and years. The other parasitoid species were Cirrospilus neotropicus, C. floridensis, Elasmus phyllocnistoides and Chrysocharis vonones, the latter constituting the first record of this species on P. citrella. Parasitoid diversity was similar between the cultivars but different between the years. The maximum temperature had the greatest effect on the miner and its parasitoids. After its establishment, P. citrella also shows correlation with the young flush. The drought periods occurring during the study might have influenced the citrus leafminer and parasitoid populations due to the reduction of available resources for both groups.