Carbon Dioxide Anesthesia ofTamarixia radiata(Hymenoptera: Eulophidae) Parasitoid ofDiaphorina citri(Hemiptera: Psyllidae)

Abstract

Tamarixia radiata (Waterston) (Hymenoptera: A T. radiata colony was maintained at Eulophidae), is an arrhenotokous ectoparasite of FDACS-DPI in Gainesville on ACP nymphs the Asian citrus psyllid (ACP) Diaphorina citri using orange jasmine, Murraya paniculata (Kuwayama) (Hemiptera; Psyllidae), vector of (1.) Jack (Sapindales: Rutaceae), as plant host citrus greening disease or huanglongbing (HLB). (Skelley & Hoy 2004). Six newly trimmed The parasitoid is reported to have controlled plants with new growth were held in an acrylic ACP populations to low levels on the islands of 62 cm cubic cage and 600 D. citri adults were Reunion, Guadeloupe and Puerto Rico (Aubert released for 72 h for oviposition a greenhouse & Quilici 1984; Etienne et al. 2001; Pluke et al. under natural sunlight 25 ± 5 °C and 50% ~ 2008). Tamarixia radiata was first imported to 70% RH. Adults were removed and plants held Florida from Taiwan and Vietnam in 1998 and for 10 d until 4th instar nymphs were available, released in 1999-2001 (Hoy & Nguyen 2001). A Plants were moved into another clean cage of survey conducted in 2006-07 determined that T. the same type for 20 days into which 100 T. ra radiata was well distributed in citrus orchards diata were released. Adult progeny were later throughout the state (Qureshi et al. 2009). Howcollected daily until no more emerged, ever, incidence of parasitism was generally low, A gas chamber was constructed consisting of a especially early in the growing season, suggesting vial, 6.50 cm in diam and 12 cm in height (Fish a need for augmenting parasitoid populations at er Scientific, Pittsburg Pennsylvania), provided that critical time as component of an integrated with two 0.50 cm diam holes in the lid into each management program (Qureshi et al. 2007,2009). of which was fitted a 0.5 cm plastic tube inserted Studies of T. radiata biology and current efforts either 1 cm or 11 cm into the chamber for a gas at mass rearing and release of this species might outlet and inlet respectively. Plasticine modeling benefit from an ability inactivate adults by C02 clay (Flair Leisure Products, Cheam Surrey, Eng anesthetization, including separation of emerland) was molded around the openings of the lid gent wasps and psyllids. to prevent leakage. Carbon dioxide (C02) is widely used to anesFlow time of gas at 3.8 kpa (2 psi) needed to thetize insects, but may also cause deleteridisplace all air in the chamber was assessed by ous side effects on biology and behavior. Brooks filling the vial with water and then replacing (1957) found that development rate of German with C02 through the inlet. All the water was dis cockroach, Blattella germanica L. (Blattodea: placed in 10 s. A C02 sensor (K-33 ICB 30% CO, Blattellidae), nymphs decreased 53% when exSensor, C02Meter Inc., Ormond Beach Florida, posed weekly to high C02 concentrations for 3 USA) was used to determine that 3 s of flow time min. Crystal (1967) reported significantly dewere necessary to attain a 30% C02 concentration creased survival rates and fertility of screwworm, confirming the earlier result. The C02 sensor was Cochliomyia homini-vorax (Coquerel) (Diptera: also used to test for leaks by confirming that a Calliphoridae), exposed to 100% C02 for 30 min. given concentration remained constant over sev Sherman (1953) reported that C02 anesthesia of eral min. Mediterranean fruit fly, Ceratitis capitata (WiFive wasps having emerged within 24 h or less edemann) (Diptera: Tephritidae), led to increased were placed in the chamber. The lower % of the mortality. vial was covered with black cloth to induce the This study was undertaken as a first step towasps to walk to the top and thus avoid injury ward using anesthetization for mass rearing by from in rushing gas. Gas was introduced through evaluating the response of T. radiata to C02 exan inlet from a C02 tank at 3.8 kpa for 15s to posure. The objective was to test the effectiveness exchange all the air, and then the 2 tubes closed of C02 anesthetization of T. radiata and to deterwith metal clamps. Wasps were removed after a mine the incidence and severity of side effects of 5 min exposure and observed with the naked eye C02 anesthetization on longevity, parasitism rate using a stop watch to record recovery time (nor and sex ratio. mal movement). Males and females were treated