Classical Biological Control of the Citrus Leafminer: Release of Cirrospilus quadristriatus
By: Marjorie A. Hoy and Ru Nguyen, University of Florida and Division of Plant Industry Department, Gainesville, and Division of Plant Industry, Gainesville
A second parasite, Cirrospilus quadristriatus (Subba Rao and Ramamani), which was collected in Australia as part of the classical biological control program for the citrus leafminer Phyllocnistis citrella (CLM), was released from quarantine in Gainesville, Florida on July 28, 1994. It is being reared in Gainesville for releases into Florida citrus groves. We hope it will establish in Florida and contribute to the biological control of the CLM.
Cirrospilus quadristriatus is a eulophid wasp that is native to subtropical and tropical regions of Asia where the CLM is found. It was introduced into Queensland, Australia as part of a classical biological control program against the CLM and collected there by M. Hoy, with the assistance of Australian scientists Dan Smith and Dan Papacek.
C. quadristriatus appears to be host specific to the CLM, with the mango flea weevil Rhynchaenus mangiferae the only other known host of this parasite in India. Although another species of this genus of wasp occurs in Florida, C. quadristriatus is new to Florida and the USA. John LaSalle, a taxonomic specialist on this group of parasites, reports that C. quadristriatus is different in appearance from the native species of Cirrospilus. An unnamed species of Cirrospilus has been found attacking the CLM in southern Florida, but the two Cirrospilus parasites can be distinguished by examining them under a compound microscope.
C. quadristriatus females deposit an egg on last instar larvae of the CLM or on prepupae within the pupal chamber. The parasite larva hatches from the egg, and develops by killing and feeding on its CLM host. C. quadristriatus then produces a single shiny black pupa within the CLM pupal chamber. Both male and female parasite adults are yellow. C. quadristriatus develop from egg to adults in about two weeks.
C. quadristriatus is being reared in Gainesville and has been released into several sites in Florida. Releases will be made into additional groves as quickly as we can rear them. As was the case with the releases of the first parasite (Ageniaspis citricola) collected from Australia, release sites will be chosen by IFAS scientists Robert Bullock, Jorge Pena, Phil Stansly, and Harold Browning, near Fort Pierce, Homestead, Immokalee, and Lake Alfred, respectively. A release has been made by David Hall near Clewiston, as well. Release sites should not have been treated with pesticides within the past year, and grove owners should commit to leaving the release site free of pesticides for the next year in order to increase the likelihood that the parasites will establish. It is also undesirable to make the releases into sites where Ageniaspis was released. Releases of Cirrospilus should occur where they can establish, at least initially, without competing with Ageniaspis. Eventually, we expect both parasites will coexist in the same grove, but suspect that separate release sites could make it easier for Cirrospilus to establish.
Originally published in The Citrus Industry magazine, November 1994.